U.S. patent application number 15/341581 was filed with the patent office on 2017-05-04 for method for enhancing anti-fatigue performance of coating.
The applicant listed for this patent is Guozheng Ma, Na Tan, Haidou Wang, Xiaoli Wang, Zhiguo Xing. Invention is credited to Guozheng Ma, Na Tan, Haidou Wang, Xiaoli Wang, Zhiguo Xing.
Application Number | 20170121808 15/341581 |
Document ID | / |
Family ID | 58637296 |
Filed Date | 2017-05-04 |
United States Patent
Application |
20170121808 |
Kind Code |
A1 |
Wang; Haidou ; et
al. |
May 4, 2017 |
METHOD FOR ENHANCING ANTI-FATIGUE PERFORMANCE OF COATING
Abstract
The present invention provides a method for enhancing the
anti-fatigue performance of coating. The method enhances the
anti-fatigue performance of coating by producing light and dark
phases with certain thickness inside of the coating, texturing of
matrix surface, texturing of coating surface, and the combination
thereof.
Inventors: |
Wang; Haidou; (Beijing,
CN) ; Xing; Zhiguo; (Beijing, CN) ; Wang;
Xiaoli; (Beijing, CN) ; Tan; Na; (Beijing,
CN) ; Ma; Guozheng; (Beijing, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Wang; Haidou
Xing; Zhiguo
Wang; Xiaoli
Tan; Na
Ma; Guozheng |
Beijing
Beijing
Beijing
Beijing
Beijing |
|
CN
CN
CN
CN
CN |
|
|
Family ID: |
58637296 |
Appl. No.: |
15/341581 |
Filed: |
November 2, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C23C 4/10 20130101; C23C
4/134 20160101; C23C 4/02 20130101 |
International
Class: |
C23C 4/134 20060101
C23C004/134; C23C 4/04 20060101 C23C004/04 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 4, 2015 |
CN |
201510740875.X |
Nov 4, 2015 |
CN |
201510740882.X |
Nov 4, 2015 |
CN |
201510740891.9 |
Nov 4, 2015 |
CN |
201510740995.X |
Nov 4, 2015 |
CN |
201510741002.0 |
Nov 4, 2015 |
CN |
201510741011.X |
Claims
1. A method for enhancing the anti-fatigue performance of coating
by controlling the internal structure of the coating, wherein the
method comprises spraying a matrix using a supersonic plasma
spraying process; and adjusting the spraying process parameters
constantly during the spraying process such that the entire coating
possesses spacing structures of light and dark layers with certain
thickness.
2. The method according to claim 1, wherein the matrix used in the
method is further subjected to cleaning and polishing
treatment.
3. The method according to claim 1, wherein the coating selected
for spraying is NiCrBSi ceramic coating, which is a sprayed coating
with a thickness of 100 .mu.m obtained by the supersonic plasma
spraying, and wherein the particle size of NiCrBSi powder is from
50 to 60 .mu.m.
4. The method according to claim 1, wherein the spraying process
uses a spraying power of 45-85 kW; for the black layer, the
spraying distance is 80-140 mm and the spraying speed is 6-10
g/min; and for the white layer, the spraying distance is 120-160 mm
and the spraying speed is 9-12 g/min.
5. The method according to claim 1, wherein the thickness of the
white layer is 4-6 .mu.m, and the thickness of the black layer is
2-7 .mu.m.
6. A method for enhancing the anti-fatigue performance of coating,
wherein the method comprises the following steps: (1) spraying a
matrix using a supersonic plasma spraying process; and (2)
subjecting a coating surface obtained in step (1) to texturing
treatment using a laser process, wherein the method is carried out
by preparing textured patterns with different geometrical
morphologies on a surface of sprayed coating by biological bionics
simulation.
7. The method according to claim 6, wherein the spraying in step
(1) employs the following process parameters: spraying voltage 120
V, spraying current 440 A, spraying power 55 kW, and spraying
distance 100 mm.
8. The method according to claim 6, wherein the laser process in
step (2) employs the following process parameters: laser power
80-120 W, scanning speed 600-900 mm/s, and frequency 15-25 HZ.
9. A method for enhancing the bonding strength of coating, wherein
the method comprises the following steps: (1) preparing textured
patterns on a matrix surface using a laser process; and (2)
subjecting the matrix obtained in step (1) to spraying using a
supersonic plasma spraying process; wherein the method is carried
out by preparing the textured patterns on the matrix surface by
biological bionics simulation, and then preparing the coating on
the matrix surface with the textured patterns.
10. A method for enhancing the fatigue strength of coating by
double-layer texture coupling effect, wherein the method includes
the following steps: (1) preparing textured patterns on a matrix
surface using a laser process; (2) subjecting the matrix obtained
in step (1) to spraying using a supersonic plasma spraying process;
and (3) subjecting the coating surface obtained in step (2) to
texturing treatment using a laser process; wherein the method is
carried out by preparing the textured patterns on the matrix
surface and the coating surface by biological bionics
simulation.
11. A method for enhancing contact fatigue performance by optimized
combination of texturing and coating process, wherein the method
comprises the following steps: (1) spraying a matrix using a
supersonic plasma spraying process; and adjusting the spraying
process parameters constantly during the spraying process such that
the entire coating possesses spacing structures of light and dark
layers with certain thickness; and (2) subjecting the coating
surface to texturing treatment using a laser process; wherein the
method is carried out by controlling the parameters during the
spraying process such that the sprayed coating possesses certain
spacing structures of light and dark layers, and then preparing
textured patterns with different morphologies on a surface of
sprayed coating by biological bionics simulation.
12. A method for enhancing the anti-fatigue performance of coating
by the coupling effect of three-layer patterning, wherein the
method comprises the following steps: (1) subjecting a matrix
surface to texturing treatment using a laser process; (2) spraying
the matrix using a supersonic plasma spraying process; (3)
adjusting the parameters during the spraying process such that the
coating possesses certain spacing structures of light and dark
layers; and (4) subjecting the coating surface to texturing
treatment using a laser process; wherein the method is carried out
by preparing textured patterns on a matrix surface and a coating
surface through biological bionics simulation; and controlling the
parameters during the spraying process such that the internal part
of the coating possesses light and dark phases with certain
thickness; and wherein the anti-fatigue performance of the coating
is improved by the mutual coupling effect of texturing of matrix
surface, the thickness of the pattern of light and dark phase of
the coating and texturing of surface.
13. A textured pattern capable of effectively enhancing the
anti-fatigue performance of sprayed coating, wherein the textured
pattern is one or more of round, triangle, hexagon, groove shape,
grid shape, arrow shape or stripe shape.
Description
TECHNICAL FIELD
[0001] The present invention refers to the technical field of
spraying materials, particularly to a method for enhancing the
anti-fatigue performance of coating.
BACKGROUND TECHNOLOGY
[0002] Because sprayed coating per se has relatively high porosity,
and has the defects such as impurities or fiber cracks, the sprayed
coating is prone to form crack propagation during the service,
resulting in reduced working life. The enhancement of the coating
performance of an existing surface mainly relies on the secondary
process technology such as laser remelting and surface
strengthening after the coating has been formed. Although these
technological means have certain effects on the enhancement of the
coating performance, these technologies can not significantly
enhance the service performance of a coating which has been formed
with fixed internal structures in nature since the macroscopical
performances are the external characterizations of internal
structures and qualities of the materials.
[0003] Sprayed coating is prone to be subjected to failure
behaviors at the coating's interfaces during its service due to the
weak binding strength thereof. Therefore, a lot of means have been
applied to pre-spraying treatment, such as shot blasting, chemical
degreasing, and the like.
[0004] However, degreasing by a chemical method can induce chemical
reactions at surfaces, introduce new oxides, and result in changes
of chemical components of a matrix surface; moreover, the employed
chemical reagents are harmful to both human bodies and environment.
Furthermore, after the completion of spraying, the matrix surface
will deform to some extent, and the resulting cavities are arranged
irregularly, the sizes and arrangements of the cavities can not be
controlled effectively. Therefore, it is necessary to explore a new
method as a pre-spraying treatment process to enhance the bonding
force between the coating and the matrix.
[0005] Supersonic plasma spraying technology is widely applied in
practical engineering field, because it can be used to prepare a
relatively thick coating on large-scale parts. Plasma spraying
technology can achieve coating of different systems by different
kinds of materials, such as metal, alloy, ceramics, metal ceramics
and plastics, and the sprayed coating also reflects different
functions, such as wear resistance, thermal barrier, electrical
conductivity, radiation protection, and the like. However, because
sprayed coating per se has relatively high porosity, and has the
defects such as impurities or fiber cracks, the sprayed coating is
prone to form crack propagation during the service, resulting in
reduced working life.
[0006] Texturing has been widely used in the research of antiwear
and friction reduction. Through the method of texturing, the
material performances have been greatly improved. The main reason
why texturing can improve the tribological properties of materials
is that it can store debris and lubricating oil, thereby provide
continuous lubrication on the friction surface. Up to date, there
are few researches on performing texturing of sprayed coating and
thereby enhancing the anti-fatigue performance of the sprayed
coating by various textured morphologies to change contact
conditions. In addition, there are also few researches on using
texturing as a pre-spraying treatment means to enhance the binding
force of the sprayed coating or as a post-processing means to
enhance the anti-fatigue performance of the sprayed coating, and
matching the textured patterns with light and dark phase structures
of sprayed coating to achieve the three-in-one textured locking
effect and to finally achieve the enhancement in the service
performance of the coating. Surface texture is a kind of bionic
surface microstructure, which is a process technology that changes
the geometry of the surface to further enhance the friction
performance of a mechanical system. Through a variety of advanced
surface microprocessing technologies (such as reactive ion etching,
surface shot blasting treatment, electron beam lithography,
mechanical micro-engraving and laser surface processing), the
surface texturing or structure patterning possesses micro
geometrical configurations (dot matrix) with particular and regular
arrangement and size structures in a manner of bionic structure
processing with special functions, so as to reduce the effective
contact area of two friction surfaces, which shows unique
advantages in terms of tribological properties of materials
especially due to the reduced friction. Therefore, it is widely
used to change the surface roughness of the parts, and then enhance
the wear resistance and anti-fatigue performance of the surface of
parts.
SUMMARY OF THE INVENTION
[0007] To enhance the working life of a coating, expand the
performances of the coating, an object of the present invention is
to provide a method for enhancing the anti-fatigue performance of
the coating.
[0008] Another object of the present invention is to provide a
textured pattern which can effectively enhance the anti-fatigue
performance of sprayed coating.
[0009] To achieve the above objects, the present invention provides
the following various embodiments.
[0010] In a first embodiment according to the present invention,
the present invention provides a method for enhancing the
anti-fatigue performance of coating by controlling the internal
structure of the coating, which method is carried out by
controlling the parameters during the spraying process such that
the sprayed coating possesses certain spacing structure of light
and dark layers.
[0011] The light and dark layers are also referred to as white and
black layers, which are coating structures with alternate white
layers and black layers; wherein the light layer (i.e. white layer)
is the part that looks brighter, and the dark layer (i.e. black
layer) is the part that looks darker.
[0012] Specifically, the method according to the first embodiment
is carried out by spraying a matrix using the supersonic plasma
spraying process; and adjusting the spraying process parameters
constantly during the spraying process such that the entire coating
possesses a spacing structure of light and dark layers with certain
thickness.
[0013] Preferably, the matrix in this method is further subjected
to cleaning and polishing treatment. The matrix is preferably
stainless steel, and particularly FV520B.
[0014] Preferably, the coating selected for the spray coating is
NiCrBSi ceramic coating, which is a sprayed coating with a
thickness of 100 .mu.m obtained by supersonic plasma spraying,
wherein the particle size of the NiCrBSi powder is 50-60 .mu.m.
[0015] Preferably, the process parameters of spraying are: spraying
power 45-85 kW; wherein, for the black layer, the spraying distance
is 80-140 mm, and the spraying speed is 6-10 g/min; and for the
white layer, the spraying distance is 120-160 mm, and the spraying
speed is 9-12 g/min.
[0016] More preferably, for the black layer, the spraying distance
is 140 mm, and the spraying speed of black layer is 10 g/min; and
for the white layer, the spraying distance is 100 mm, and the
spraying speed is 8 g/min.
[0017] Preferably, the thickness of white layer and black layer is
1-7 .mu.m.
[0018] More preferably, the thickness of white layer is 4-6 .mu.m,
and the thickness of black layer is 2-7 .mu.m. Most preferably, the
white layer is 5 .mu.m, and the black layer is 4 .mu.m.
[0019] According to the first embodiment, the present invention
provides a textured pattern that can effectively enhance the
anti-fatigue performance of sprayed coating. The pattern includes
any of geometric patterns or combination of several geometric
patterns, such as round, triangle, hexagon, groove shape, grid
shape, arrow shape or stripe shape, and the like.
[0020] More preferably, the density of the textured pattern is
greater than 0% and less than 50%; the density means the area ratio
of the textured pattern with respect to the surface of matrix or
coating.
[0021] The advantageous effect of the first embodiment is as
follows: by controlling the spacing and thickness of light and dark
layers of the coating, the performances of coating can be
optimized, such that the service performance and anti-fatigue
performance of the entire sprayed coating is enhanced.
[0022] In a second embodiment according to the present invention,
the present invention provides a method for enhancing the
anti-fatigue performance of coating, which method is carried out by
preparing textured patterns with different geometrical morphologies
on the surface of sprayed coating through biological bionics
simulation. The present invention uses the method of texturing
after spraying, with the hope of providing continuous lubrication
by means of texturing, changing the slip ratio of rolling contact
fatigue, thereby investigating the contact fatigue performance of
coating, and with the hope of optimizing the textured pattern based
on this, thereby prolonging the service performance of coating.
[0023] Specifically, the method according to the second embodiment
includes the following steps:
[0024] (1) spraying a matrix using a supersonic plasma spraying
process; and
[0025] (2) subjecting a coating surface to texturing treatment
using a laser process.
[0026] Preferably, the matrix in step (1) of the method is further
subjected to cleaning and polishing treatment. The matrix is
preferably stainless steel, and particularly FV520B.
[0027] Preferably, in step (1), the process parameters of spraying
are: spraying voltage of 120 V, spraying current of 440 A, spraying
power of 55 kW, and spraying distance of 100 mm. The coating
selected for spraying is NiCrBSi ceramic coating, which is a
sprayed coating with a thickness of about 100 .mu.m obtained by
supersonic plasma spraying, wherein the particle size of the
NiCrBSi powder is 50-60 .mu.m.
[0028] Preferably, the specific process parameters of the laser
process in step (2) are: laser power of 80-120 W, scanning speed of
600-900 mm/s, and frequency of 15-25 HZ. By controlling the depth
of the selected texture through controlling the laser energy, a
regular textured pattern with certain size and certain density can
be obtained by laser texturing method.
[0029] In this embodiment, the laser used is pulse laser, the
energy and the processing times used determine the depth of the
textured pattern; by the drawing software that comes with the
system, the desired textured pattern with certain size and certain
shape according to certain spacing can be drawn in advance, then
the specimen surface can be possessed to obtain the textured
pattern with fine size structure.
[0030] According to the second embodiment, the present invention
provides a textured pattern that can effectively enhance the
anti-fatigue performance of sprayed coating. The pattern includes
any of geometric patterns or combination of several geometric
patterns, such as one or more of round, triangle, hexagon, groove
shape, grid shape, arrow shape or stripe shape.
[0031] More preferably, the textured pattern has an arrow
shape.
[0032] More preferably, the density of the textured pattern is
greater than 0% and less than 50%; and the density means the area
ratio of textured pattern with respect to the surface of matrix or
coating.
[0033] The advantageous effect of the second embodiment is as
follows: the coating surface is textured; due to the fact that the
difference in morphologies of textured pattern can change the
contact conditions, and thereby results in the change in the
contacting force, it can effectively enhance the anti-fatigue
performance of coating.
[0034] In a third embodiment according to the present invention,
the present invention provides a method for enhancing the bonding
strength of coating, which method is carried out by preparing a
textured pattern on a matrix surface through biological bionics
simulation; and then preparing a coating on the matrix surface with
the textured pattern.
[0035] Specifically, the method according to the third embodiment
includes the following steps:
[0036] (1) preparing a textured pattern on a matrix surface using a
laser process; and
[0037] (2) subjecting the matrix obtained in step (1) to spraying
using s supersonic plasma spraying process.
[0038] Preferably, the matrix in step (1) of above method is
further subjected to cleaning and polishing treatment. The matrix
is preferably stainless steel, and particularly FV520B.
[0039] Preferably, in step (1), the specific process parameters of
laser process are: laser power of 80-120 W, scanning speed of
600-900 mm/s, and frequency of 15-25 HZ. The process controls the
depth of the selected texture by controlling the processing times.
The processing times are 3-7 times. A regular textured pattern with
certain size and certain density can be obtained by laser texturing
method.
[0040] Preferably, in step (2), the process parameters of spraying
are: spraying voltage of 120V, spraying current of 440 A, spraying
power of 55 kW, and spraying distance of 100 mm. The coating
selected for spraying is NiCrBSi ceramic coating, which is a
sprayed coating with a thickness of about 100 .mu.m obtained by
supersonic plasma spraying, wherein the particle size of the
NiCrBSi powder is 50-60 .mu.m.
[0041] In this embodiment, the laser used is pulse laser, and the
energy and the processing times used determine the depth of
textured pattern; by the drawing software that comes with the
system, the desired textured pattern with certain size and certain
shape according to certain spacing can be drawn in advance, then
the specimen surface can be possessed to obtain the textured
pattern with fine size structure.
[0042] According to the third embodiment, the present invention
provides a textured pattern that can effectively enhance the
bonding strength of sprayed coating. The pattern includes any of
geometric patterns or combination of several geometric patterns,
such as round, triangle, hexagon, groove shape, grid shape, arrow
shape or stripe shape, and the like.
[0043] Preferably, the density of the textured pattern is greater
than 0% and less than 50%; and more preferably 30%.
[0044] The advantageous effect of the third embodiment is as
follows: texturing is used as a pre-spraying treatment means; by
texturing, the bonding strength of sprayed coating is enhanced,
thereby the service performance of coating is prolonged.
[0045] In a fourth embodiment according to the present invention,
the present invention provides a method for enhancing the fatigue
strength of coating by double-layer texture coupling effect, which
method is carried out by preparing a textured pattern on matrix
surface and coating surface by biological bionics simulation.
Surface texture is a type of biomimetic surface microstructure,
which is a process technology that alters surface geometric
configuration, thereby enhancing the friction property of
mechanical system. Before spraying, the matrix surface is subjected
to texturing because the textured pattern increases the contacting
area of the coating and provides more locking point for the
coating, it improves the bonding strength of sprayed coating, and
texturing of coating surface improves the friction property of the
material because it can increase the storage degree.
[0046] Specifically, the method according to the Fourth includes
the following steps:
[0047] (1) preparing a textured pattern on a matrix surface using a
laser process;
[0048] (2) subjecting the matrix obtained in step (1) to spraying
using a supersonic plasma spraying process; and
[0049] (3) subjecting a coating surface obtained in step (2) to
texturing treatment using a laser process.
[0050] Preferably, the matrix in step (1) of above method is
further subjected to cleaning and polishing treatment. The matrix
is preferably stainless steel, and particularly FV520B.
[0051] Preferably, in step (1), the specific process parameters of
laser process are: laser power of 80-120 W, scanning speed of
600-900 mm/s, and frequency of 15-25 HZ. The process controls the
depth of the selected texture by controlling the processing times.
The processing times are 3-7 times. A regular textured pattern with
certain size and certain density can be obtained by laser texturing
method.
[0052] Preferably, in step (2), the process parameters of spraying
are: spraying voltage of 120 V, spraying current of 440 A, spraying
power of 55 kW, and spraying distance of 100 mm. The coating
selected for spraying is NiCrBSi ceramic coating, which is a
sprayed coating with a thickness of about 100 .mu.m obtained by
supersonic plasma spraying, wherein the particle size of the
NiCrBSi powder is 50-60 .mu.m.
[0053] Preferably, in step (3), the specific process parameters of
laser process are: laser power of 80-120 W, scanning speed of
600-900 mm/s, and frequency of 15-25 HZ. By controlling the depth
of the selected texture through controlling the laser energy, a
regular textured pattern with certain size and certain density can
be obtained by laser texturing method.
[0054] In this embodiment, the laser used is pulse laser, and the
energy and the processing times used determine the depth of
textured pattern; by the drawing software that comes with the
system, the desired textured pattern with certain size and certain
shape according to certain spacing can be drawn in advance, then
the specimen surface can be possessed to obtain the textured
pattern with fine size structure.
[0055] According to the fourth embodiment, the present invention
provides a textured pattern that can effectively enhance the
anti-fatigue performance of sprayed coating. The pattern includes
any of geometric patterns or combination of several geometric
patterns, such as round, triangle, hexagon, groove shape, grid
shape, arrow shape or stripe shape, and the like.
[0056] Preferably, the density of the textured pattern is greater
than 0% and less than 50%; and the density means the area ratio of
textured pattern with respect to the surface of matrix or
coating.
[0057] The advantageous effect of the fourth embodiment is as
follows: texturing is used as combined means of pre-spraying
treatment and post-treatment of spraying; the bonding strength of
sprayed coating is enhanced by texturing, and the anti-contact
fatigue performance of sprayed coating is improved by surface
texturing, thereby the service performance of the coating is
prolonged.
[0058] In a fifth embodiment according to the present invention,
the present invention provides a method for enhancing contact
fatigue performance by optimized combination of texturing and
coating process, which method is carried out by controlling the
parameters during the spraying process such that the sprayed
coating possesses certain spacing structures of light and dark
layers, and then preparing a textured pattern with different
morphologies on a surface of sprayed coating by biological bionics
simulation. The light and dark layers are also referred to as white
and black layers, which are coating structures with alternate white
layers and black layers; wherein the light layer (i.e. white layer)
is the part that looks brighter, and the dark layer (i.e. black
layer) is the part that looks darker.
[0059] Specifically, the method according to the fifth embodiment
includes the following steps:
[0060] (1) spraying a matrix using a supersonic plasma spraying
process and adjusting the spraying process parameters constantly
during the spraying, such that the entire coating possesses spacing
structures of light and dark layers with certain thickness; and
[0061] (2) subjecting the surface of the coating to texturing
treatment using a laser process.
[0062] Preferably, the matrix in step (1) of the method is further
subjected to cleaning and polishing treatment. The matrix is
preferably stainless steel, and particularly FV520B.
[0063] Preferably, The coating selected for spraying is NiCrBSi
ceramic coating, which is a sprayed coating with a thickness of 100
.mu.m obtained by supersonic plasma spraying, wherein the particle
size of the NiCrBSi powder is 50-60 .mu.m.
[0064] Preferably, the process parameters of spraying are: spraying
power of 45-85 kW; wherein, for the black layer, the spraying
distance is 80-140 mm, and the spraying speed is 6-10 g/min; and
for the white layer, the spraying distance is 120-160 mm, and the
spraying speed is 9-12 g/min.
[0065] More preferably, for the black layer, the spraying distance
is 140 mm, and the spraying speed is 10 g/min; and for the white
layer, the spraying distance is 100 mm, and the spraying speed is 8
g/min.
[0066] Preferably, the thickness of white layer and black layer is
1-7 .mu.m.
[0067] More preferably, the thickness of white layer is 4-6 .mu.m,
and the thickness of black layer is 2-7 .mu.m.
[0068] Preferably, the specific process parameters of the laser
process in step (2) are: laser power of 80-120 W, scanning speed of
600-900 mm/s, and frequency of 15-25 HZ. By controlling the depth
of the selected texture through controlling the laser energy, a
regular textured pattern with certain size and certain density can
be obtained by laser texturing method.
[0069] In the embodiment, the laser used is pulse laser, and the
energy and the processing times used determine the depth of
textured pattern; by the drawing software that comes with the
system, the desired textured pattern with certain size and certain
shape according to certain spacing can be drawn in advance, then
the specimen surface can be possessed to obtain the textured
pattern with fine size structure.
[0070] According to the fifth embodiment, the present invention
provides a textured pattern that can effectively enhance the
anti-fatigue performance of sprayed coating. The pattern includes
any of geometric patterns or combination of several geometric
patterns, such as round, triangle, hexagon, groove shape, grid
shape, arrow shape or stripe shape, and the like.
[0071] Preferably, the textured pattern has an arrow shape.
[0072] More preferably, the density of the textured pattern is
greater than 0% and less than 50%; and the density means the area
ratio of textured pattern with respect to the surface of matrix or
coating.
[0073] The advantageous effect of the fifth embodiment is as
follows: by controlling the spacing and thickness of light and dark
layers of the coating, the performance of the coating can be
optimized; meanwhile, by use of the method of matching the spacing
of the internal light and dark layers of the coating and the
texturing of coating surface, the service performance and
anti-fatigue performance of the entire sprayed coating can be
enhanced.
[0074] In a sixth embodiment according to the present invention,
the present invention provides a method for enhancing the
anti-fatigue performance of coating by the coupling effect of three
layer patterning, which method is carried out by preparing a
textured pattern on matrix surface and coating surface by
biological bionics simulation; controlling the parameters during
the spraying process such that the coating possesses light and dark
phases with certain thickness therein; and enhancing the
anti-fatigue performance of the coating by the mutual coupling
effect of surface texturing of the matrix, thickness of the pattern
of light and dark phases of the coating and surface texturing of
the coating.
[0075] Specifically, the method according to the sixth embodiment
includes the following steps:
[0076] (1) subjecting a matrix surface to texturing treatment using
a laser process;
[0077] (2) spraying the matrix using a supersonic plasma spraying
process; and
[0078] (3) adjusting the parameters during the spraying process
such that the coating possesses a certain structure of light and
dark phases; and
[0079] (4) subjecting the coating surface to texturing treatment
using a laser process.
[0080] Preferably, the matrix in step (1) of above method is
further subjected to cleaning and polishing treatment. The matrix
is preferably stainless steel, and particularly FV520B.
[0081] Preferably, in step (1), the specific process parameters of
laser process are: laser power of 80-120 W, scanning speed of
600-900 mm/s, and frequency of 15-25 HZ. The process controls the
depth of the selected texture by controlling the processing times.
The processing times are 3-7 times. A regular textured pattern with
certain size and certain density can be obtained by laser texturing
method.
[0082] Preferably, in step (2), the process parameters of spraying
are: spraying voltage of 120 V, spraying current of 440 A, spraying
power of 55 kW, and spraying distance of 100 mm. The coating
selected for spraying is NiCrBSi ceramic coating, which is a
sprayed coating with a thickness of 100 .mu.m obtained by
supersonic plasma spraying, wherein the particle size of the
NiCrBSi powder is 50-60 .mu.m.
[0083] Preferably, in step (3), the process parameters of spraying
are: spraying power of 45-85 kW; wherein, for the black layer, the
spraying distance is 80-140 mm, and the spraying speed is 6-10
g/min; and for the white layer, the spraying distance is 120-160
mm, and the spraying speed is 9-12 g/min; the thickness of light
and dark layers of the coating is white layer of 4-6 .mu.m and
black layer of 2-7 .mu.m, respectively. More preferably, the white
layer is 5 .mu.m, and the black layer is 4 .mu.m.
[0084] Preferably, in step (4), the specific process parameters of
laser process are: laser power of 80-120 W, scanning speed of
600-900 mm/s, and frequency of 15-25 HZ. By controlling the depth
of the selected texture through controlling the laser energy, a
regular textured pattern with certain size and certain density can
be obtained by laser texturing method.
[0085] According to the sixth embodiment, the present invention
provides a textured pattern that can effectively enhance the
anti-fatigue performance of sprayed coating. The pattern includes
any of geometric patterns or combination of several geometric
patterns, such as round, triangle, hexagon, groove shape, grid
shape, arrow shape or stripe shape, and the like.
[0086] More preferably, the density of the textured pattern is
greater than 0% and less than 50%; and the density means the area
ratio of textured pattern with respect to the surface of matrix or
coating.
[0087] In this embodiment, the laser used is pulse laser, and the
energy and the processing times used determine the depth of
textured pattern; by the drawing software that comes with the
system, the desired textured pattern with certain size and certain
shape according to certain spacing can be drawn in advance, then
the specimen surface can be possessed to obtain the textured
pattern with fine size structure.
[0088] The advantageous effect of the sixth embodiment is as
follows: texturing of coating surface can effectively enhance the
anti-fatigue performance of coating, because difference in the
morphologies of textured pattern can change the contact conditions,
thereby resulting in changes of contacting force; texturing of
coating interfaces can effectively enhance the bonding strength of
the coating, because the introduction of texturing can provide more
anchor points for the coating; and the three-dimensional integrated
textured pattern formed by matchment of texturing and the structure
of the light and dark phases of the coating itself can enhance the
service performance of coating. Therefore, the coupling effect of
the three layer patterns regarding surface texturing of matrix,
surface texturing of coating and structures of internal light and
dark phases of coating can significantly enhance the anti-fatigue
performance of coating.
DESCRIPTION OF THE FIGURES
[0089] FIG. 1 shows the variation curve of the hardness of coating
surface with the thickness of white layer of light and dark layers
of the coating in Example 1;
[0090] FIG. 2 shows the variation curve of the fatigue strength of
coating with the thickness of white layer of light and dark layers
of the coating in Example 1;
[0091] FIG. 3 shows the textured pattern performed on coating
surface in Example 2;
[0092] FIG. 4 shows the fatigue strength of coating with different
texture shapes on the surface of the coating of the present
invention;
[0093] FIG. 5 shows the fatigue performance of coating with
different angles of stripes.
[0094] FIG. 6 shows the textured pattern performed on the surface
of the matrix in Example 3 of the present invention;
[0095] FIG. 7 shows the bonding strength between coating and matrix
under the circumstances that the matrix surface has texture of
different shapes in Example 3;
[0096] FIG. 8 shows variation of bonding strength with different
texture densities of coating in Example 3;
[0097] FIG. 9 shows the schematic drawing of the coupling effect of
double layer texturing in matrix surface and coating surface of the
present invention;
[0098] FIG. 10 shows variation of fatigue strength with bonding
strength of coating;
[0099] FIG. 11 shows variation of fatigue strength with hardness of
coating; and
[0100] FIG. 12 shows the schematic drawing of the coupling effect
of three-layer texture by texturing of matrix surface, internal
light and dark layers of coating and texturing of coating surface
according to the present invention.
REFERENCE SIGNS
[0101] matrix 1, coating 2, texturing of matrix surface 3,
texturing of coating surface 4, internal light and dark layers of
coating 5.
PREFERRED EMBODIMENTS
[0102] The advantageous effect of the present invention is further
described by Examples hereinafter.
[0103] It should be appreciated that these Examples are only used
for the purpose of illustration, and they are by no means used to
limit the protection scope of the present invention.
Example 1
[0104] The Example refers to the preparation of coating according
to the above first embodiment of the present invention.
[0105] Step 1:
[0106] The matrix was subjected to cleaning and polishing treatment
at first. The matrix is preferably stainless steel, and
particularly FV520B.
[0107] Step 2:
[0108] A high-efficiency GTV F6 plasma spraying equipment from
General Research Institute of mining and metallurgy was selected as
the spraying equipment; the process parameters of spraying were:
spraying voltage 120 V, spraying current 440 A, spraying power 55
kW, and spraying distance 100 mm. A coating with certain thickness
was eventually obtained. The coating selected for spraying was
NiCrBSi ceramic coating, which was a sprayed coating with a
thickness of 100 .mu.m obtained by supersonic plasma spraying,
wherein the particle size of the NiCrBSi powder was 56 .mu.m.
[0109] The process parameters of spraying were as follows: the
spraying power is 80 kW, the spraying distance of black layer was
140 mm, the spraying speed was 10 g/min; the spraying distance of
white layer was 100 mm, the spraying speed was 8 g/min; the
thickness of light and dark layers of the obtained coating was:
white layer of 5 .mu.m, and black layer of 4 .mu.m.
Example 2
[0110] The coating prepared in Example 1 was subjected to rolling
contact fatigue test, and the slip ratios of contact fatigue were
changed to investigate the anti-fatigue performance of coating
under the conditions of different slip ratios.
[0111] To measure various performances of the coating, Nova
NanoSEM450 type scanning electron microscope was used to observe
the geometrical morphology of the texture after spraying.
[0112] To measure the influence of different textured patterns on
the anti-fatigue performance of sprayed coating, a rolling contact
fatigue testing machine was used to test the fatigue performance of
sprayed coating.
[0113] 1. Variation of Coating Hardness with the Thickness of White
Layer in Light and Dark Phases of Coating
[0114] Coatings in which the white layer in the coating had a
thickness of 1-3 .mu.m, 2-4 .mu.m, 3-5 .mu.m, 4-6 .mu.m, and 5-7
.mu.m respectively were subjected to fatigue test using fatigue
testing machine, and the testing results were shown in FIG. 1. It
was found that, the fatigue strength of coating varied with the
thickness of white layer in the coating; and when the thickness of
white layer in the coating was 4-6 .mu.m, the fatigue strength of
coating was the maximum, 780 HV.
[0115] 2. Variation of the Anti Fatigue Strength with the Hardness
of Coating
[0116] Coatings with different hardness were subjected to fatigue
test using a rolling contact fatigue testing machine. It was found
that, the fatigue strength of coating was increased with the
increase of the hardness of the coating, as shown in FIG. 2.
Therefore, the thickness of light and dark layers corresponding to
the maximum hardness, i.e. white layer of 4-6 .mu.m, was selected
to obtain better anti-fatigue performance.
Example 3
[0117] The Example refers to the preparation of textured coating
according to the above second embodiment of the present
invention.
[0118] Step 1:
[0119] A matrix was subjected to cleaning and polishing treatment
at first. The matrix is preferably stainless steel, and
particularly FV520B.
[0120] Step 2:
[0121] The matrix was sprayed using the supersonic plasma spraying
method.
[0122] In the step (2), a high-efficiency GTV F6 plasma spraying
equipment from General Research Institute of mining and metallurgy
was selected as the spraying equipment, the process parameters of
spraying were: spraying voltage 120 V, spraying current 440 A,
spraying power 55 kW, and spraying distance 100 mm. A coating with
certain thickness was eventually obtained.
[0123] The coating selected for spraying was NiCrBSi ceramic
coating, which was a sprayed coating with a thickness of about 100
.mu.m obtained by supersonic plasma spraying, wherein the particle
size of the NiCrBSi powder was 56 .mu.m.
[0124] Step 3:
[0125] The coating surface was subjected to texturing treatment
using a laser process.
[0126] The laser power was 80 W, the scanning speed was 600 mm/s,
and the frequency was 20 HZ. By laser texturing method, a textured
pattern could be obtained with a depth of 60 m and a density of
30%. The specific patterns were: round and stripe shapes, hexagon,
triangle, arrow shape, and stripe shape, as shown in FIG. 3.
[0127] Among these, the stripe shape had a width of 50 .mu.m and a
strip spacing of 70 .mu.m, as shown in FIG. 3-1;
[0128] the combination of round and stripe shapes, wherein the
stripe shape had a width of 50 .mu.m and a strip spacing was 70
.mu.m; the round shape was evenly distributed in the stripe shape
texture, with a diameter of 50 .mu.m, as shown in FIG. 3-2;
[0129] the arrow shape had a width of 60 .mu.m, wherein the width
was the vertical distance of two sides, and the spacing of each
arrow was 70 .mu.m, as shown in FIG. 3-3;
[0130] the hexagon had a side length of 60 .mu.m and a spacing of
70 .mu.m, as shown in FIG. 3-4; and
[0131] the triangle had a side length of 95 .mu.m, and the spacing
between fixed points of bases of two triangles was 70 .mu.m, which
were not shown in the Figure.
Comparative Example 1
[0132] Except for the absence of texturing, experimental comparison
was carried out under the same condition parameters as in Example
3.
Example 4
[0133] The coating prepared in Example 3 was subjected to rolling
contact fatigue test, and the slip ratios of contact fatigue were
changed to investigate the anti-fatigue performance of coating
under the conditions of different slip ratios.
[0134] To measure various performances of the coating, Nova
NanoSEM450 type scanning electron microscope was used to observe
the geometrical morphology of the texture after spraying.
[0135] To measure the influence of different textured patterns on
the anti-fatigue performance of sprayed coating, a rolling contact
fatigue testing machine was used to test the fatigue performance of
sprayed coating.
[0136] 1. Fatigue Strength of Coating when the Coating Surface has
Different Shapes of Textures
[0137] To test the influence of textured pattern of coating on the
bonding strength of coating, the textured coating was subjected to
fatigue strength test, the equipment used was conventional fatigue
testing machine. The testing results are shown in FIG. 4: the
bonding strength of non-textured coating surface was 500 MPa, and
the fatigue strength of coating surfaces with different shapes of
texture were between 500 MPa and 600 MPa. Compared with
non-textured coating surface, coating surfaces with textured
pattern possessed better anti-fatigue strength, and the fatigue
strength of coating varied with the shape of textured pattern.
Among the selected patterns, arrow shape texture had the best
fatigue strength, 580 MPa.
[0138] 2. Variation of Fatigue Strength with Angles of Arrow Shape
Texture
[0139] To test the influence of angles of arrow shape texture on
the fatigue strength of coating, the angles of arrow shape were
changed: the angles of prepared arrow shape were 15 degree, 25
degree, 35 degree, and 45 degree. The prepared patterns with
different angles of arrow shape were subjected to fatigue test, and
the used testing machine was the conventional testing machine.
[0140] The testing results are shown in FIG. 5, which shows
variation of the fatigue strength of coating with angles of arrow
texture. It can be seen that, the fatigue strength of coating
varied with texturing angles, and texturing angles had an optimal
value. When the angle of arrow texture was at 35 degree, the
fatigue strength of coating was the highest.
Example 5
[0141] The Example refers to the preparation of coating according
to the above third embodiment of present invention.
[0142] Step 1:
[0143] A matrix was subjected to cleaning and polishing treatment
at first. The matrix was preferably stainless steel, and
particularly FV520B.
[0144] Step 2:
[0145] Textured pattern was prepared on matrix surface using a
laser process.
[0146] Firstly, patterns of combined texture of round and triangle,
combined texture of round and groove shape, grid texture, and
hexagon texture were drawn with drawing software, then textured
patterns were prepared on matrix surface using a laser processing,
as shown in FIG. 6.
[0147] Among these, hexagon texture had a side length of 150 .mu.m
and a spacing of 200 .mu.m, as shown in FIG. 6-1.
[0148] Combined texture of round and groove shape, wherein the
width of groove was 150 .mu.m and the spacing was 200 .mu.m; within
the spacing of groove, rounds with a diameter of 100 .mu.m and a
lengthwise spacing of 200 .mu.m were arranged, is shown in FIG.
6-2;
[0149] combined texture of round and triangle, wherein the round
had a diameter of 150 .mu.m and a center spacing of 200 .mu.m, and
triangles with a side length of 100 .mu.m were prepared in the gaps
between rounds, as shown in FIG. 6-3;
[0150] grid texture was distributed with grooves in both transverse
and longitudinal direction, wherein the width of grooves was 150
.mu.m and the spacing was 200 .mu.m, as shown in FIG. 6-4;
[0151] the specific process parameters of laser processing process:
the used laser power was 90 W, the scanning speed was 700 mm/s, and
the frequency was 20 HZ. The depth of textured pattern was
controlled by the processing times, and the processing times was 6.
Textured pattern with a depth of 80 .mu.m was obtained, and the
density of the textured pattern was 30%.
[0152] Step 3:
[0153] Spraying was carried out using a supersonic plasma spraying
process.
[0154] A high-efficiency GTV F6 plasma spraying equipment from
General Research Institute of mining and metallurgy was selected as
the spraying equipment in step (3). Process parameters of spraying
were: spraying voltage 120 V, spraying current 440 A, spraying
power 55 kW, and spraying distance 100 mm. A coating with certain
thickness was eventually obtained. The coating selected for
spraying was NiCrBSi ceramic coating, which was a sprayed coating
with a thickness of about 100 .mu.m obtained by supersonic plasma
spraying, wherein the particle size of the NiCrBSi powder was 56
.mu.m.
Comparative Example 2
[0155] Except for the absence of texturing, experimental comparison
was carried out under the same condition parameters as in Example
5.
Example 6
[0156] The coating prepared by Example 5 was subjected to rolling
contact fatigue test, and the slip ratios of contact fatigue were
changed to investigate the anti-fatigue performance of coating
under the conditions of different slip ratios.
[0157] To measure various performances of the coating, Nova
NanoSEM450 type scanning electron microscope was used to observe
the geometrical morphology of the texture after spraying.
[0158] To measure the influence of different textured patterns on
the anti-fatigue performance of sprayed coating, a rolling contact
fatigue testing machine was used to test the fatigue performance of
sprayed coating.
[0159] 1. Bonding Strength Between Coating and Matrix in Case of
Different Shapes of Texture on Matrix Surface
[0160] A tensile tester was used to test the bonding strength of
coating, in which the model number of the used tensile tester was
MTS809 type electronic universal material testing machine. The
manufacturer was MTS Company (USA). The textured patterns with
different shapes prepared by Example 5 were then subjected to
spraying, then subjected to tensile test. The final bonding
strength was obtained by dividing the force for the coating to
break from the matrix with the area of coating, and the testing
results are shown in FIG. 7. The bonding strength of the
non-textured matrix surface was 50 MPa, but when the matrix surface
had different shapes of textures, the bonding strength between
coating and matrix was between 60 MPa and 70 MPa. Compared with
non-textured matrix surface, textured pattern significantly
enhanced the bonding strength of coating, and the bonding strength
of coating varied with the shape of textured pattern. Among the
selected patterns, grid pattern had the best bonding strength,
which was 68 MPa.
[0161] 2. Variation of Bonding Strength with the Density of
Textured Pattern
[0162] The density means the area ratio of textured pattern with
respect to the surface of matrix or coating. To test the influence
of the density of textured pattern on bonding strength, the density
of grid shape textured pattern was selected. The prepared texturing
degree was 15%, 20%, 25%, 30%, and 35%. The prepared grid shape
patterns with different densities were subjected to fatigue test,
and the used testing machine was conventional testing machine. The
testing results are shown in FIG. 8, which shows variation of the
bonding strength of coating with grid texture density. It can be
seen that, the bonding strength of coating varied with texturing
density, and bonding strength showed the trend of first increasing
and then decreasing, and the texturing density had an optimal
value; when grid texture density was at 30%, the bonding strength
of coating was the highest.
Example 7
[0163] The Example refers to the preparation of the double-layer
texture coupled coating according to the above fourth embodiment of
the present invention.
[0164] Step 1:
[0165] A matrix was subjected to cleaning and polishing treatment
at first. The matrix was preferably stainless steel, and
particularly FV520B.
[0166] Step 2:
[0167] Textured pattern was prepared on matrix surface using a
laser process.
[0168] Firstly, patterns of combined texture of round and triangle,
combined texture of round and groove shape, grid texture, and
hexagon texture were drawn with drawing software, then textured
patterns were prepared on matrix surface using a laser
processing.
[0169] Among these, for combined texture of round and triangle, the
round had a diameter of 150 .mu.m and a center spacing of 200
.mu.m, triangles with a side length of 100 .mu.m were prepared in
the gaps between rounds;
[0170] combined texture of round and groove shape, wherein the
width of groove was 150 .mu.m and the spacing was 200 .mu.m; within
the spacing of groove, rounds with a diameter of 100 .mu.m and a
lengthwise spacing of 200 .mu.m were arranged;
[0171] grid texture was distributed with grooves in both transverse
and longitudinal direction, wherein the width of grooves was 150
.mu.m and the spacing was 200 .mu.m; and
[0172] hexagon texture had a side length of 150 .mu.m and a spacing
of 200 .mu.m.
[0173] The specific process parameters of laser processing process
were as follows: the used laser power was 90 W, the scanning speed
was 700 mm/s, and the frequency was 20 HZ. The depth of textured
pattern was controlled by the processing times, and the processing
times was 6. Textured pattern with a depth of 80 .mu.m was
obtained; and the density of the textured pattern was 30%.
[0174] Step 3:
[0175] Spraying was carried out using a supersonic plasma spraying
process.
[0176] A high-efficiency GTV F6 plasma spraying equipment from
General Research Institute of mining and metallurgy was selected as
the spraying equipment in step (3). Process parameters of spraying
were: spraying voltage 120 V, spraying current 440 A, spraying
power 55 kW, and spraying distance 100 mm. A coating with certain
thickness was eventually obtained. The coating selected for
spraying was NiCrBSi ceramic coating, which was a sprayed coating
with a thickness of about 100 .mu.m obtained by supersonic plasma
spraying, wherein the particle size of the NiCrBSi powder was 56
.mu.m.
[0177] Step 4:
[0178] Coating surface was subjected to texturing treatment using a
laser process.
[0179] The laser power was 80 W, the scanning speed was 600 mm/s,
and the frequency was 20 HZ. By laser texturing method, textured
pattern with a depth of 60 .mu.m and a density of 40% can be
obtained. The specific patterns were: round and stripe shapes,
hexagon, triangle, arrow shape, and stripe shape.
[0180] For the combination of round and stripe shapes, the stripe
shape width was 50 .mu.m, the stripe spacing was 70 .mu.m, rounds
having a diameter of 50 .mu.m were evenly distributed in the stripe
shape texture;
[0181] hexagon had a side length of 60 .mu.m, and a spacing of 70
.mu.m;
[0182] triangle had a side length of 95 .mu.m, and the spacing of
fixed points of bases of two triangle was 70 .mu.m;
[0183] arrow shape had a width of 60 .mu.m; the width is the
vertical distance of two sides, and the spacing of each arrow was
70 .mu.m;
[0184] stripe shape had a width of 50 .mu.m, and a spacing of 70
.mu.m.
[0185] Among these, the schematic drawing of double-layer texture
coupled coating with the matrix surface being coating surface of
grid shape and the coating surface being arrow shape is shown in
FIG. 9.
Comparative Example 3
[0186] Using the same condition parameters as Example 7, sprayed
coating was prepared on non-textured matrix to conduct experimental
comparison.
Example 8
[0187] The coating prepared by Example 7 was subjected to rolling
contact fatigue test, and the slip ratios of contact fatigue were
changed to investigate the anti-fatigue performance of coating
under the conditions of different slip ratios.
[0188] To measure various performances of the coating, Nova
NanoSEM450 type scanning electron microscope was used to observe
the geometrical morphology of the texture after spraying.
[0189] To measure the influence of different textured patterns on
the anti-fatigue performance of sprayed coating, a rolling contact
fatigue testing machine was used to test the fatigue performance of
sprayed coating.
[0190] 1. Bonding Strength Between Coating and Matrix in Case of
Different Shapes of Texture on Matrix Surface
[0191] A tensile tester was used to test the bonding strength of
coating, the model number of the used tensile tester was MTS809
type electronic universal material testing machine. The
manufacturer was MTS company (USA). The textured patterns with
different shapes prepared by Example 7 were then subjected to
spraying, and then subjected to tensile test. The final bonding
strength was obtained by dividing the force for the coating to
break from the matrix with the area of coating. The results
indicated that, compared with non-textured matrix surface, textured
pattern significantly enhanced the bonding strength of coating, and
the bonding strength of coating varied with the shape of textured
pattern. Among the selected patterns, grid pattern had the best
bonding strength.
[0192] 2. Fatigue Strength of Coating when the Coating Surface has
Different Shapes of Textures
[0193] To test the influence of textured patterns of coating on the
bonding strength of coating, the textured coating was subjected to
fatigue strength test, and the used equipment was conventional
fatigue testing machine. The results indicated that, compared with
non-textured coating surface, coating surface with textured pattern
possessed better anti-fatigue strength, and the fatigue strength of
coating varied with the shape of textured pattern. Among the
selected patterns, arrow shape texture had the best fatigue
strength.
[0194] 3. Variation of the Fatigue Strength with Bonding Strength
of Coating
[0195] To test the variation of fatigue strength with bonding
strength of coating, variation of fatigue strength of coating with
bonding strength (i.e., the bonding strength of coating obtained in
point 1) were tested on the basis of the textured patterns on
matrix surface in step 1. The used equipment was fatigue testing
machine, whose model number and manufacturer are the same as in
point 2.
[0196] The testing results are shown in FIG. 10, which is the
variation curve of the fatigue strength with bonding strength of
coating. It can be seen that, the fatigue strength of coating was
increased with the increase of bonding strength, i.e. the coupling
effect of double layer textures can significantly enhance the
fatigue strength of coating.
[0197] 4. Variation of Fatigue Strength with the Angles of Arrow
Shape Texture
[0198] To test the influence of angles of arrow shape texture in
point 2 of Example 8 on the fatigue strength of coating, the angles
of arrow shape were changed: the angles of prepared arrow shape
were 15 degree, 25 degree, 35 degree, and 45 degree. The prepared
arrow shape patterns with different angles were subjected to
fatigue test, and the used testing machine was the same as that in
point 2 of Example 8. The results indicated that, the fatigue
strength of coating varied with texturing angles, and texturing
angles had an optimal value: when arrow texture angles were at 35
degree, and the fatigue strength of coating was the highest.
Example 9
[0199] The Example refers to the preparation of coupled coating
according to the above fifth embodiment of the present
invention.
[0200] Step 1:
[0201] A matrix was subjected to cleaning and polishing treatment
at first. The matrix was preferably stainless steel, and
particularly FV520B.
[0202] Step 2:
[0203] A high-efficiency GTV F6 plasma spraying equipment from
General Research Institute of mining and metallurgy was selected as
the spraying equipment in the step (2). The coating selected for
spraying was NiCrBSi ceramic coating, which was a sprayed coating
with a thickness of about 100 .mu.m obtained by supersonic plasma
spraying, wherein the particle size of the NiCrBSi powder was 56
.mu.m.
[0204] The process parameters of spraying were: spraying power 80
kW; the spraying distance of black layer was 140 mm, the spraying
speed was 10 g/min; and the spraying distance of white layer was
100 mm, the spraying speed was 8 g/min; the thickness of light and
dark layers of the obtained coating was: white layer of 5 .mu.m,
and black layer of 4 .mu.m.
[0205] Step 3:
[0206] Coating surface was subjected to texturing treatment using a
laser process.
[0207] The laser power was 80 W, the scanning speed was 600 mm/s,
and the frequency was 20 HZ. By laser texturing method, textured
pattern with a depth of 60 .mu.m and a density of 40% can be
obtained. The specific patterns were: round and stripe shapes,
hexagon, triangle, arrow shape, and stripe shape.
[0208] For the combination of round and stripe shapes, the width of
stripe shape was 50 .mu.m, the stripe spacing was 70 .mu.m, and
rounds having a diameter of 50 .mu.m were evenly distributed in the
stripe shape texture;
[0209] hexagon had a side length of 60 .mu.m, and a spacing of 70
.mu.m;
[0210] triangle had a side length of 95 .mu.m, and the spacing of
fixed points of bases of two triangle was 70 .mu.m;
[0211] arrow shape had a width of 60 .mu.m; the width is the
vertical distance of two sides, and the spacing of each arrow was
70 .mu.m;
[0212] stripe shape had a width of 50 .mu.m, and a spacing of 70
.mu.m.
Comparative Example 4
[0213] Except for the absence of texturing, experimental comparison
was carried out under the same condition parameters as in Example
9.
Example 10
[0214] The coating prepared by Example 9 was subjected to rolling
contact fatigue test, and the slip ratios of contact fatigue were
changed to investigate the anti-fatigue performance of coating
under the conditions of different slip ratios.
[0215] To measure various performances of the coating, Nova
NanoSEM450 type scanning electron microscope was used to observe
the geometrical morphology of the texture after spraying.
[0216] To measure the influence of different textured patterns on
the anti-fatigue performance of sprayed coating, a rolling contact
fatigue testing machine was used to test the fatigue performance of
sprayed coating.
[0217] 1. Variation of Coating Hardness with the Thickness of White
Layer in Light and Dark Phases of Coating
[0218] The coating wherein the white layer in the coating had a
thickness of 1-3 .mu.m, 2-4 .mu.m, 3-5 .mu.m, 4-6 .mu.m, and 5-7
.mu.m, respectively, was subjected to fatigue test using fatigue
testing machine. It was found that, the fatigue strength of coating
varied with the thickness of white layer in the coating; when the
thickness of white layer in coating was 4-6 .mu.m, the fatigue
strength of coating was the maximum, 780 HV.
[0219] 2. Variation of the Anti Fatigue Strength with Hardness of
Coating
[0220] Coatings with different hardness were subjected to fatigue
test using a rolling contact fatigue testing machine. It was found
that, the fatigue strength of coating was increased with the
increase of the hardness of coating. Therefore, the thickness of
light and dark layers corresponding to the maximum hardness, i.e.
white layer 4-6 .mu.m, was selected to obtain better anti-fatigue
performance.
[0221] 3. Fatigue Strength of Coating when the Coating Surface has
Different Shapes of Textures
[0222] To test the influence of textured pattern of coating on the
bonding strength of coating, the textured coating was subjected to
fatigue strength test, and the used equipment was conventional
fatigue testing machine. The results indicated that, the bonding
strength of non-textured coating surface was 500 MPa, and the
fatigue strength of coating surface with different shapes of
texture was between 500 MPa and 600 MPa. Compared with non-textured
coating surface, coating surface with textured pattern possessed
better anti-fatigue strength, and the fatigue strength of coating
varied with the shape of textured pattern. Among the selected
patterns, arrow shape texture had the best fatigue strength, 590
MPa.
[0223] 4. Variation of Fatigue Strength with Angles of Arrow Shape
Texture
[0224] To test the influence of angles of arrow shape texture in
point 3 of Example 10 on the fatigue strength of coating, the
angles of arrow shape were changed: the angles of prepared arrow
shape were 15 degree, 25 degree, 35 degree, and 45 degree. The
prepared arrow shape patterns with different angles were subjected
to fatigue test, and the used testing machine was the same as that
in point 2. The results indicated that, the fatigue strength of
coating varied with texturing angles, and texturing angles had an
optimal value: when arrow texture angles were at 35 degree, the
fatigue strength of coating was the highest.
Example 11
[0225] The Example refers to the preparation of three-layer texture
coupled coating according to the above sixth embodiment of present
invention.
[0226] Step 1:
[0227] A matrix was subjected to cleaning and polishing treatment
at first. The matrix was preferably stainless steel, and
particularly FV520B.
[0228] Step 2:
[0229] The matrix surface was subjected to texturing treatment
using a laser process.
[0230] Firstly, patterns of combined texture of round and triangle,
combined texture of round and groove shape, grid texture, and
hexagon texture were drawn with drawing software, then textured
patterns were prepared on matrix surface using a laser
processing.
[0231] Among these, for combined texture of round and triangle: the
round had a diameter of 150 .mu.m and a center spacing of 200
.mu.m, triangles with a side length of 100 .mu.m were prepared in
the gaps between rounds;
[0232] combined texture of round and groove shape, wherein the
width of groove was 150 .mu.m and a spacing was 200 .mu.m; within
the spacing of groove, rounds with a diameter of 100 .mu.m and a
lengthwise spacing of 200 .mu.m were arranged;
[0233] grid texture was distributed with grooves in both transverse
and longitudinal direction, wherein the width of grooves was 150
.mu.m and the spacing was 200 .mu.m; and
[0234] hexagon texture had a side length of 150 .mu.m, a spacing of
200 .mu.m.
[0235] The specific process parameters of laser processing process
were as follows: the used laser power was 90 W, the scanning speed
was 700 mm/s, and the frequency was 20 HZ. The depth of textured
pattern was controlled by the processing times, and the processing
times was 6. Textured pattern with a depth of 80 .mu.m was
obtained; and the density of the textured pattern was 30%.
[0236] Step 3:
[0237] Spraying was carried out using a supersonic plasma spraying
process.
[0238] A high-efficiency GTV F6 plasma spraying equipment from
General Research Institute of mining and metallurgy was selected as
the spraying equipment in the step (3). Process parameters of
spraying were: spraying voltage 120 V, spraying current 440 A,
spraying power 55 kW, and spraying distance 100 mm. A coating with
certain thickness was eventually obtained. The coating selected for
spraying was NiCrBSi ceramic coating, which was a sprayed coating
with a thickness of about 100 .mu.m obtained by supersonic plasma
spraying, wherein the particle size of the NiCrBSi powder was 56
.mu.m.
[0239] Step 4:
[0240] The parameters during the spraying process were adjusted,
such that the coating had a certain structure of light and dark
phases.
[0241] The process parameters of spraying in step (4) were as
follows: the spraying power was 80 kW, the spraying distance of
black layer was 140 mm, the spraying speed was 10 g/min; and the
spraying distance of white layer was 100 mm, the spraying speed was
8 g/min; the thickness of light and dark layers of the obtained
coating was: white layer of 5 .mu.m, and black layer of 4
.mu.m.
[0242] Step 5:
[0243] Coating surface was subjected to texturing treatment using a
laser process.
[0244] The laser power was 80 W, the scanning speed was 600 mm/s,
and the frequency was 20 HZ. By laser texturing method, textured
pattern with a depth of 60 .mu.m and a density of 40% can be
obtained. The specific patterns were: round and stripe shapes,
hexagon, triangle, arrow shape, and stripe shape.
[0245] For the combination of round and stripe shapes, the width of
stripe shape was 50 .mu.m, the stripe spacing was 70 .mu.m, rounds
having a diameter of 50 .mu.m were evenly distributed into the
stripe shape texture;
[0246] hexagon had a side length of 60 .mu.m, and a spacing of 70
.mu.m;
[0247] triangle had a side length of 95 .mu.m, and the spacing of
fixed points of bases of two triangle was 70 .mu.m;
[0248] arrow shape had a width of 60 .mu.m; the width is the
vertical distance of two sides, and the spacing of each arrow was
70 .mu.m;
[0249] stripe shape had a width of 50 .mu.m, and a spacing of 70
.mu.m.
[0250] Among these, matrix surface was coating surface of grid
shape. The schematic drawing of three-layer texture coupled coating
with the coating surface of arrow shape is shown in FIG. 11.
Comparative Example 5
[0251] Under the circumstances of the same condition parameters as
Example 11, sprayed coating was prepared on non-textured matrix to
conduct experimental comparison.
Example 12
[0252] The coating prepared by Example 11 was subjected to rolling
contact fatigue test, and the slip ratios of contact fatigue were
changed to investigate the anti-fatigue performance of coating
under the conditions of different slip ratios.
[0253] To measure various performances of the coating, Nova
NanoSEM450 type scanning electron microscope was used to observe
the geometrical morphology of the texture after spraying.
[0254] To measure the influence of different textured patterns on
the anti-fatigue performance of sprayed coating, a rolling contact
fatigue testing machine was used to test the fatigue performance of
sprayed coating.
[0255] 1. Bonding Strength Between Coating and Matrix in Case of
Different Shapes of Texture on Matrix Surface
[0256] A tensile tester was used to test the bonding strength of
coating, and the model number of the used tensile tester was MTS809
type electronic universal material testing machine. The
manufacturer was MTS company (USA). The textured patterns with
different shapes prepared by Example 11 were then subjected to
sprayed coating, then subjected to tensile test. The final bonding
strength was obtained by dividing the force for the coating to
break from the matrix with the area of coating. The results
indicated that, the bonding strength of the non-textured matrix
surface was 50 MPa, but when the matrix surface had different
shapes of textures, the bonding strength between coating and matrix
was between 60 MPa and 70 MPa. Compared with non-textured matrix
surface, textured pattern significantly enhanced the bonding
strength of coating, and the bonding strength of coating varied
with the shape of textured pattern. Among the selected patterns,
grid pattern had the best bonding strength, which was 68 MPa.
[0257] 2. Variation of Bonding Strength with the Density of
Textured Pattern
[0258] To test the influence of the density of textured pattern on
bonding strength, the density of grid shape textured pattern was
selected. The prepared texturing densities were 15%, 20%, 25%, 30%,
and 35%. The prepared grid shape patterns with different densities
were subjected to fatigue test, and the used testing machine was
conventional testing machine. The results indicated that, the
bonding strength of coating varied with texturing density, and
bonding strength showed the trend of first increasing and then
decreasing, and texturing density had an optimal value; when grid
texture density was at 30%, the bonding strength of coating was the
highest.
[0259] 3. Fatigue Strength of Coating when the Coating Surface has
Different Shapes of Textures
[0260] To test the influence of textured pattern of coating on the
bonding strength of coating, the textured coating was subjected to
fatigue strength test, and the used equipment was conventional
fatigue testing machine. The results indicated that, the bonding
strength of non-textured coating surface was 500 MPa, and the
fatigue strength of coating surface with different shapes of
texture was between 500 MPa and 600 MPa. Compared with non-textured
coating surface, coating surface with textured pattern possessed
better anti-fatigue strength, and the fatigue strength of coating
varied with the shape of textured pattern. Among the selected
patterns, arrow shape texture had the best fatigue strength, 590
MPa.
[0261] 4. Variation of the Fatigue Strength of Coating with Bonding
Strength
[0262] To test the variation of fatigue strength with bonding
strength of coating, variation of fatigue strength of coating with
bonding strength (i.e., the bonding strength of coating obtained in
point 1) was preferably tested on the basis of the textured
patterns on matrix surface in step 1. The used equipment was
fatigue testing machine, whose model number and manufacturer was
the same as in point 2. The results indicated that, the fatigue
strength of coating was increased with the increase of bonding
strength, i.e. the coupling effect of three layer textures can
significantly enhance the fatigue strength of coating.
[0263] 5. Variation of Fatigue Strength with the Angles of Arrow
Shape Texture
[0264] To test the influence of angles of arrow shape texture in
point 3 on the fatigue strength of coating, the angles of arrow
shape were changed: the angles of prepared arrow shape were 15
degree, 25 degree, 35 degree, and 45 degree. The prepared arrow
shape patterns with different angles were subjected to fatigue
test, and the used testing machine was the same as that in point 2
of Example 12. The results indicated that, the fatigue strength of
coating varied with texturing angles, and texturing angles had an
optimal value: when arrow texture angle was at 35 degree, the
fatigue strength of coating was the highest.
[0265] 6. Variation of the Fatigue Strength of Coating with Light
and Dark Phases of Coating
[0266] The coating wherein the white layer in the coating had a
thickness of 1-3 .mu.m, 2-4 .mu.m, 3-5 .mu.m, 4-6 .mu.m, and 5-7
.mu.m, respectively, was subjected to fatigue test using fatigue
testing machine. The results indicated that, the fatigue strength
of coating varied with the thickness of white layer in the coating;
and when the thickness of white layer in coating was 4-6 .mu.m, the
fatigue strength of coating was the maximum, 780 HV.
[0267] 7. Variation of Coating Hardness with the Thickness of White
Layer in Light and Dark Phases of the Coating
[0268] The hardness of the coating was tested by microhardness
tester, and variation of coating hardness with the thickness of the
light and dark layers was explored. The results indicated that,
when the thickness of white layer in coating was 4-6 .mu.m, the
hardness of coating was the maximum, 780 HV.
[0269] 8. Variation of the Anti-Fatigue Strength of Coating with
Hardness
[0270] Coatings with different hardness were subjected to fatigue
test using a rolling contact fatigue testing machine, and the
testing results were shown in FIG. 12. It is found that, the
fatigue strength of coating was increased with the increase of the
hardness of coating.
[0271] The above described are only the preferred embodiments of
the present invention. It should be noted that, those skilled in
the art can also make several changes and modifications without
departing from the technical principles of the present invention,
and these changes and modifications should also be regarded as
within the protection scope of the present invention.
* * * * *