U.S. patent application number 10/630874 was filed with the patent office on 2004-04-29 for sintered material product and method for manufacturing the same.
This patent application is currently assigned to NIHON PARKERIZING CO., LTD.,MITSUBISHI MATERIALS CORPORATION. Invention is credited to Kodama, Tokunori, Maruyama, Tsuneo, Mori, Kazuhiko, Nakano, Sinnosuke, Shimizu, Teruo.
Application Number | 20040079188 10/630874 |
Document ID | / |
Family ID | 31492225 |
Filed Date | 2004-04-29 |
United States Patent
Application |
20040079188 |
Kind Code |
A1 |
Mori, Kazuhiko ; et
al. |
April 29, 2004 |
Sintered material product and method for manufacturing the same
Abstract
A sintered copper alloy material product is provided on which a
skin (particularly, a skin of a solid lubricant with low adhesion,
such as PTFE or molybdenum disulfide) is securely formed on the
surface thereof and has good sliding properties and good seizure
resistance under unlubricating environments or under corrosive
environments. A sintered copper alloy material is processed using a
selective chemical etching solution containing a compound of one
kind or more selected from the group of consisting of peroxide,
peroxocompound, chromic acid and permanganic acid and a compound of
one kind or more selected from the group of consisting of
phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid,
hydrofluoric acid, zirconic hydrofluoric acid, titanic hydrofluoric
acid, titanic acid, molybdic acid, tungstic acid, vanadic acid,
niobic acid, and organic chelating agent. Thereafter, a lubricating
skin is on the surface of the processed material.
Inventors: |
Mori, Kazuhiko; (Tokyo,
JP) ; Nakano, Sinnosuke; (Tokyo, JP) ; Kodama,
Tokunori; (Tokyo, JP) ; Shimizu, Teruo;
(Niigata, JP) ; Maruyama, Tsuneo; (Niigata,
JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
NIHON PARKERIZING CO.,
LTD.,MITSUBISHI MATERIALS CORPORATION
|
Family ID: |
31492225 |
Appl. No.: |
10/630874 |
Filed: |
July 31, 2003 |
Current U.S.
Class: |
75/230 ;
75/236 |
Current CPC
Class: |
C10N 2030/06 20130101;
C23C 22/07 20130101; C10M 2213/062 20130101; B22F 7/004 20130101;
F16C 33/12 20130101; F16C 33/201 20130101; B22F 2999/00 20130101;
B22F 2003/244 20130101; C10M 2201/066 20130101; C10M 2201/053
20130101; C10M 103/06 20130101; C09D 179/08 20130101; C10N 2030/12
20130101; B22F 2999/00 20130101; B22F 2301/10 20130101 |
Class at
Publication: |
075/230 ;
075/236 |
International
Class: |
C22C 009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 5, 2002 |
JP |
JP2002-227797 |
Claims
What is claimed is:
1 A sintered material product comprising: a sintered copper alloy
material; and a skin formed on said sintered copper alloy material;
said sintered copper alloy material having pores each having an
inlet diameter of 10 to 200 .mu.m; wherein an average value of
(inlet pore diameter)/(inner pore diameter) of each of said pores
is 2 or more.
2 The sintered material product claimed in claim 1, wherein a
porosity of said pores is 2 to 35% by volume and said average value
of (inlet pore diameter)/(inner pore diameter) is 2 to 20.
3 The sintered material product claimed in claim 1, further
comprising a layer of metal phosphate and/or metal oxide underneath
of said skin.
4 The sintered material product claimed in claim 1, wherein said
skin is a skin comprising a solid lubricant.
5 A method for manufacturing a sintered material product having a
sintered copper alloy material and a skin formed on said sintered
copper alloy material; comprising the steps of: (A) processing said
sintered copper alloy material with a selective chemical etching
solution; and (C) forming a skin on a surface of said sintered
copper alloy material, after the step (A).
6 The method claimed in claim 5, further comprising the steps of:
(B) forming a layer of metal phosphate and/or metal oxide on the
surface of said sintered copper alloy material, after said step (A)
and before said step (C).
7 The method claimed in claim 5, wherein said selective chemical
etching solution comprises a solution containing a compound of one
kind or more selected from the group consisting of peroxide,
peroxocompound, chromic acid, and permanganic acid.
8 The method claimed in claim 5, wherein said selective chemical
etching solution comprises a solution containing a compound of one
kind or more selected from the group consisting of peroxide,
peroxocompound, chromic acid, and permanganic acid and a compound
of one kind or more selected from the group consisting of
phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid,
hydrofluoric acid, zirconic hydrofluoric acid, titanic hydrofluoric
acid, titanic acid, molybdic acid, tungstic acid, vanadic acid,
niobic acid, and organic chelating agent.
9 The method claimed in claim 6, wherein said step (B) comprises
the step of processing said sintered copper alloy material with a
solution of a metal compound of one kind or more selected from the
group consisting of Zn, Ca, Mg, Mn, Ni, Co, Mo, W, Cu, Sn, Ti, Zr,
V, In, and Cr.
10 The method claimed in claim 5, further comprising the step of
ultrasonic cleaning said sintered copper alloy material after said
step (A) and before said step (C).
11 The method claimed in claim 5, further comprising the step of
processing said sintered copper alloy material with a solution
containing an organic alkali compound after said step (A) and
before said step (C).
12 The method claimed in claim 6, further comprising the step of
ultrasonic cleaning said sintered copper alloy material after said
step (B) and before said step (C).
13 The method claimed in claim 6, further comprising the step of
processing said sintered copper alloy material with a solution
containing an organic alkali compound after said step (B) and
before said step (C).
14 The method claimed in claim 5, wherein said skin comprises a
solid lubricant.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a sintered material product
used for transportation machines such as automobiles, ships, other
general industrial machinery, household electric appliances, OA
equipment, and building materials or printing. Particularly, the
present invention relates to a sintered material product having
good sliding properties and good corrosion resistance.
[0002] Copper alloys, which have good heat, electrical conduction
and good corrosion resistance, and good workability, have been used
in various industrial fields such as buildings, printings,
electrical facilities, automobiles, and others. Particularly,
copper alloys with good corrosion resistance and good sliding
properties are broadly used for sliding parts in various gears,
guide rails, automobile parts, household electric appliances,
pumps, motors, OA equipment, and others.
[0003] In environments where the lubricating oil cannot be used and
a long-term durability is required, the slide surface is subjected
to a surface treatment.
[0004] For example, it has been proposed to form on the slide
surface a fluorocarbon resin coating, which is superior in
weathering resistance, dirt prevention, water repellent, and
lubricating characteristic. Alternatively, it has been proposed to
form on the slide surface a functional ceramic film, which has heat
resistance, wear resistance, hydrophilicity, photocatalyst
property, and far-infrared reflection function.
[0005] However, the above-mentioned films generally have poor
adhesion to a sintered copper alloy being a substrate, thus
resulting in poor durability.
[0006] JP-P1993-157115A discloses the method of impregnating a
resin, such as polyamide or polyimide, into a sintered copper
alloy. The above-mentioned resins tend to be easily impregnated
into pores of the sintered copper alloy, thus providing good
adhesion to the sintered alloy material.
[0007] However, compared with films of fluorocarbon resin such as
PTFE (polytetrafluoro-ethylene), the above-mentioned resin films
are poor in sliding properties, so that a sufficient sliding
performance cannot be obtained.
[0008] In contrast, compared with resins such as polyamide and
polyimide, it is difficult to impregnate fluorocarbon resins such
as PTFE into pores of a sintered copper alloy. Hence, the
fluorocarbon resins show poor adhesive property to copper
alloys.
[0009] A solid lubricant such as molybdenum disulfide indicates a
tendency similar to those of fluorocarbon resins.
[0010] In order to improve the film adhesive property, it has been
considered to blast the sintered copper alloy with sands or ceramic
particles.
[0011] This blasting technique improves the adhesive property but
blast particles pierce the substrate (of a soft copper alloy). The
pierced blast particles wear and deform the opposite material and
degrade the seizure resistance or durability. For that reason, the
blasting technique cannot be employed to sintered copper alloy
products.
SUMMARY OF THE INVENTION
[0012] The present invention is made to solve the above-mentioned
problems.
[0013] An object of the present invention is to provide a sintered
copper alloy material product having good sliding properties and
good durability.
[0014] Another object of the present invention is to provide a
sintered copper alloy material product on which a skin
(particularly, a skin of a solid lubricant with low adhesion, such
as PTFE or molybdenum disulfide) is securely formed on the surface
thereof.
[0015] Further another object of the present invention is to
provide a sintered copper alloy material product having good
sliding properties and good durability under unlubricating
environments or corrosive environments.
[0016] The present inventor has studied aggressively to solve the
above-mentioned problems. As a result, a component prone to
corrosion (an easy-corrosive component) such as zinc contained in a
copper alloy corrodes under severe corrosive environment so that an
oxidation product is produced. It was found that the corrosion
accelerates seizure. In order to prevent the earlier seizure, it
was considered to apply a solid lubricant, such as PTFE or
molybdenum disulfide, on the surface of the substrate (a sintered
copper alloy material). However, the solid lubricant shows poor
adhesion to the substrate (a sintered copper alloy material).
Consequently, this approach proved that a sufficient effect could
not be obtained.
[0017] Further investigation has been aggressively made by the
present inventor. Using a solution containing a compound of one
kind or more selected from the group consisting of peroxide,
peroxocompound, chromic acid and permanganic acid, easy-corrosive
components or oxide products were removed selectively. Thereafter,
a skin of a solid lubricant such as PTFE or molybdenum disulfide
was formed. Products produced thus have the skin invaded into pores
of the substrate (a sintered copper alloy material). This
conformation has an improved skin adhesion. Furthermore, it has
been known that the removal of the corrosive product leads to an
improved durability (corrosion resistance).
[0018] The present invention was made based on the above-mentioned
knowledge.
[0019] The above-mentioned problems are solved by the following
manufacturing methods. That is, a method for manufacturing a
sintered material product having a sintered copper alloy material
and a skin formed on the sintered copper alloy material, comprises
the steps of (A) processing said sintered copper alloy material
with a selective chemical etching solution, and (C) forming a skin
on the surface of said sintered copper alloy material after the
step (A).
[0020] Particularly, a method for manufacturing a sintered material
product having a sintered copper alloy material and a skin formed
on the sintered copper alloy material, comprises the step of (A)
processing the sintered copper alloy material with a selective
chemical etching solution, (B) forming a layer of a metal phosphate
and/or a metal oxide on the surface of the sintered copper alloy
material after the step (A), and (C) forming a skin on the surface
of the sintered copper alloy material after the step (B).
[0021] The processing temperature and the processing time of
selective chemical etching solution are not restricted, unless
specified. The processing temperature is, for example, a room
temperature to 50.degree. C. The processing time is, for example, 1
to 10 minutes.
[0022] The sintered product produced thus has the following
structure.
[0023] That is, the sintered copper alloy material has pores of
which the inlet diameter ranges from 10 .mu.m to 200 .mu.m. The
average value of (inlet pore diameter)/(inner pore diameter) of
each pore is 2 or more. Particularly, (inlet pore diameter)/(inner
pore diameter) is 2 to 20. The porosity is 2 to 35% by volume.
[0024] Moreover, a layer of a metal phosphate and/or metal oxide is
formed underneath of the skin.
[0025] The selective chemical etching solution used in the step (A)
is, preferably, a solution containing a compound of one kind or
more selected from the group consisting of peroxide,
peroxocompound, chromic acid, and permanganic acid. Particularly,
the etching solution is, preferably, an aqueous solution containing
peroxide or peroxocompound.
[0026] As peroxocompound are listed, for example, peroxosulfuric
acid, peroxophosphoric acid, peroxovanadic acid, peroxoniobic acid,
peroxotantalic acid, peroxoboric acid, peroxotitanic acid,
peroxotungstic acid, peroxomolybdic acid, and peroxochromic acid.
Soluble salt of the above-mentioned acids, particularly,
peroxosulfuric acid and salt thereof, may be used. Particularly,
ammonium salt, sodium salt, and potassium salt of peroxodisulfuric
acid is preferable.
[0027] The peroxide is preferably hydrogen peroxide.
[0028] The preferable concentration of peroxide or peroxocompound
is 1 to 30% by weight (particularly, 3 to 20% by weight). The
reason is that an excessively low concentration results in a small
selective removing effect of easy-corrosive components or oxides.
In contrast, an excessively high concentration results in
precipitation of crystals and instability of etching solution.
[0029] The selective chemical etching solution contains,
preferably, peroxide or peroxocompound, as well as a compound of
one kind or more selected from the group consisting of phosphoric
acid, sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric
acid, zirconic hydrofluoric acid, titanic hydrofluoric acid,
titanic acid, molybdic acid, tungstic acid, vanadic acid, niobic
acid, and organic chelating agent (preferably, tartaric acid,
citric acid, EDTA, organic phosphonic acid, or phytic acid, having
a chelating effect to copper).
[0030] A selective chemical etching solution, having a preferable
combination, is an aqueous solution including, for example,
phosphoric acid-peroxosulfuric acid, peroxophosphoric acid-sulfuric
acid, phosphoric acid-hydrogen peroxide, tartaric acid-hydrogen
peroxide, phosphoric acid-nitric acid-hydrogen peroxide, or
sulfuric acid-hydrogen peroxide. pH of the selective chemical
etching solution is preferably 1 to 5. pH is adjusted appropriately
using alkalis such as aqueous ammonia, ammonium carbonate, sodium
hydroxide, sodium carbonate, or potassium hydroxide.
[0031] In the present invention, peroxide and peroxocompound are
especially used for the following reasons. That is, the desired
selective etching cannot be realized though the mechanical surface
roughening method using the blasting process or through the
chemical etching using common acid or alkali. The selective etching
can be effectively realized using peroxide or peroxocompound. The
skin is formed on the sintered copper alloy material after the step
(A) so as to invade into the surface thereof. This can provide a
very high anchor effect and high skin adhesion.
[0032] After the step (A), it is preferable to process the sintered
copper alloy material using a solution containing a metal compound
of one kind or more selected the group consisting of Zn, Ca, Mg,
Mn, Ni, Co, Mo, W, Cu, Sn, Ti, Zr, V, In, and Cr.
[0033] For example, a sintered copper alloy material is processed
using a metal ion aqueous solution of sulfate, acetate, chloride,
phosphate, carbonate, or hydroxide of the above-mentioned metals or
using colloidal sol of the above-mentioned metals oxide. Thus, a
metal phosphate layer and/or a metal oxide layer is formed on the
surface of the sintered copper alloy material subjected to the
selective chemical etching. A preferable thickness of the layer is
0.1 to 2 .mu.m (preferably, 0.2 to 1 .mu.m). This layer improves
the corrosion resistance. The adhesiveness between the layer and
the skin formed on the layer is improved.
[0034] After the step (A) and the step (B), it is preferable to
rinse quickly the sintered copper alloy material in water. In other
words, acids left in the sintered copper alloy material are removed
by water washing. For example, the acid remaining in the sintered
copper alloy material causes a degradation of corrosion resistance.
It is particularly preferable to subject the sintered copper alloy
material to ultrasonic cleaning. That is, the smut remaining in the
surface of the sintered copper alloy material is removed through
the ultrasonic cleaning, so that the material surface with good
adhesive property can be obtained.
[0035] After the water rinsing, it is preferable to process the
sintered copper alloy material with an aqueous solution containing
organic alkali compound (e.g. alkanolamine). This process
neutralizes the acid remaining in the sintered copper alloy
material, thus improving the corrosion resistance. Moreover, the
adhesive property of the skin formed on the sintered copper alloy
material is improved. Low molecular compounds, each of which the
molecular structure has at least one amino group, are preferable as
organic alkali compounds. For example, as low molecular compounds
are listed monoethanolamine, diethanolamine, trietanolamine,
morpholine, derivatives of them, and alkoxysilane having various
amino groups. These compounds improve the surface adhesive property
of a solid lubricative skin and the wetting property of paint.
[0036] A skin (particularly, a solid lubricant skin) is formed on
the surface of the sintered copper alloy material processed as
shown above.
[0037] A coating film containing a solid lubricant is listed as the
skin. As solid lubricants are appropriately used, for example,
polytetrafluoro-ethylene (PTFE),
tetrafluoroperfluoroalkylvinylethercopol- ymer (PFA), graphite,
molybdenum disulfide, tungsten disulfide, boron nitride, tungsten
fluoride, titanium nitride. As binder components of a coating film
are listed, for example, resins such as polyester, polyolefin,
polyurethane, polyacryl, polyamide, polyimide, epoxy, and silicone.
As these paints can be used, for example, FL-J4668 produced by
Nihon Parkerizing Co., Ltd. and EB3 and LHF4B produced by Kawamura
Research Laboratories, Inc. A paint containing the various
components is applied on the sintered copper alloy material using
the splay method, the dipping method, the roll coating method, the
powder method or the electro-deposition method and then is baked,
so that a painted film is formed. The thickness of the painted film
is preferably, for example, 1 to 40 .mu.m (particularly, the film
thickness is 2 to 20 .mu.m or 1 to 10 .mu.m).
[0038] According to the present invention, the sintered copper
alloy contains copper. The content of copper is preferably 20 to
95% by weight (is, particularly, 50 to 90% by weight). In addition,
as a component other than Cu is listed, for example, Zn, Fe, Mn,
Al, Co, P, Mo, Sn, Ni or C. Specifically, the sintered copper alloy
material is B031, B110, B062, or B060.
[0039] Prior to the selective chemical etching process, it is
preferable to degrease and clean the sintered copper alloy
material. Thus, oil contents adhering to the surface of the
sintered copper alloy material are removed.
[0040] The products produced as described above proved that the
durability and the seizure resistance (sliding property) are
remarkably improved.
DESCRIPTION OF THE EMBODIMENTS
[0041] A sintered material product according to the present
invention includes a sintered copper alloy material and a skin
formed on the sintered copper alloy material. The skin is,
particularly, a paint film containing a solid lubricant.
[0042] The sintered copper alloy material has pores. The inlet of
each pore has a diameter of 10 to 200 .mu.m (particularly, 20 to
100 .mu.m). An average value of (inlet pore diameter)/(inner pore
diameter) is 2 or more (particularly, 2 to 20, or 5 to 20). The
porosity is 2 to 35% by volume (particularly, 10 to 25% by
volume).
[0043] The porous sintered copper alloy material is obtained by
processing a sintered copper alloy material with a selective
chemical etching solution. For example, a sintered copper alloy
material is dipped in a selective chemical etching solution.
Alternatively, a selective chemical etching solution may be sprayed
onto the sintered copper alloy material. In other way, the surface
of the sintered copper alloy material may be wetted with a
selective chemical etching solution according to the flow coating
method. The processing temperature is a room temperature to
50.degree. C. The processing time is about 1 to 10 minutes.
[0044] In the sintered material product of the present invention, a
layer of metal phosphate and/or metal oxide is formed between the
skin and the sintered copper alloy material.
[0045] The present invention relates to the method for
manufacturing a sintered material product having a sintered copper
alloy material and a skin formed on the sintered copper alloy
material. This manufacturing method includes the step (A) of
processing a sintered copper alloy material with a selective
chemical etching solution. After the step (A), the manufacturing
method has the step (C) of forming a skin on the surface of the
sintered copper alloy material. The manufacturing method further
has the step (B) of forming a layer of metal phosphate and/or metal
oxide on the surface of the sintered copper alloy material between
step (A) and the step (C).
[0046] The selective chemical etching solution used in the step (A)
is preferably a solution containing a compound of one kind or more
selected from the group consisting of peroxide, peroxocompound,
chromic acid and permanganic acid. Particularly, the etching
solution is preferably an aqueous solution containing peroxide or
peroxocompound.
[0047] As peroxocompounds are listed peroxosulfuric acid,
peroxophosphoric acid, peroxovanadic acid, peroxoniobic acid,
peroxotantalic acid, peroxoboric acid, peroxotitanic acid,
peroxotungstic acid, peroxomolybdic acid, and peroxochromic acid.
Soluble salts of the above-mentioned acids may be used.
Particularly, peroxosulfuric acid or salt thereof, may be used.
Particularly, ammonium salt, sodium salt, and potassium salt of
peroxodisulfuric acid is preferable. The peroxide is preferably
hydrogen peroxide.
[0048] The preferable concentration of peroxide or peroxocompound
is 1 to 30% by weight (particularly, 3 to 20% by weight).
[0049] The selective chemical etching solution contains,
preferably, peroxide or peroxocompound, as well as a compound of
one kind or more selected from the group consisting of phosphoric
acid, sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric
acid, zirconic hydrofluoric acid, titanic hydrofluoric acid,
titanic acid, molybdic acid, tungstic acid, vanadic acid, niobic
acid, and organic chelating agent (for example, tartaric acid,
citric acid, EDTA, organic phosphonic acid, or phytic acid).
[0050] A selective chemical etching solution, having a preferable
combination, is an aqueous solution including, for example,
phosphoric acid-peroxosulfuric acid, peroxophosphoric acid-sulfuric
acid, phosphoric acid-hydrogen peroxide, tartaric acid-hydrogen
peroxide, phosphoric acid-nitric acid-hydrogen peroxide, or
sulfuric acid-hydrogen peroxide.
[0051] pH of the selective chemical etching solution is preferably
1 to 5. pH is adjusted appropriately using alkalis such as aqueous
ammonia, ammonium carbonate, sodium hydroxide, sodium carbonate, or
potassium hydroxide.
[0052] If the selective chemical etching solution does not contain
acid (e.g. phosphoric acid) or organic chelating agent, it is
considered that after the selective chemical etching process, post
treatment may be carried out with acid (e.g. phosphoric acid) or
with an organic chelating agent. However, this approach results in
an increased number of production steps.
[0053] After the step (A), the step (B) is carried out, if
necessary. In other words, after the selective chemical etching
process, the sintered copper alloy material is processed with a
solution containing metal compounds. A preferable metal, used in
such a step, is Zn, Ca, Mg, Mn, Ni, Co, Mo, W, Cu, Sn, Ti, Zr, V,
In, or Cr. For example, a sintered copper alloy material is
processed using an aqueous solution of sulfate, acetate, chloride,
phosphate, carbonate, or hydroxide of the above-mentioned metals
(having a concentration of 0.02 to 2% by weight). Alternatively,
the sintered copper alloy material may be processed using colloidal
sol of a metal oxide. Thus, a layer of metal phosphate and/or metal
oxide, having a thickness of 0.1 to 2 .mu.m (preferably, 0.2 to 1
.mu.m), is formed.
[0054] After the step (A) or the step (B), it is preferable, if
necessary, to rinse quickly the sintered copper alloy material in
water (particularly, to perform ultrasonic cleaning to it). This
process removes acids left in the sintered copper alloy
material.
[0055] After the water rinsing, the sintered copper alloy material
is processed, if necessary, with an aqueous solution containing
organic alkali compound. Low molecular compounds, each of which the
molecular structure has at least one amino group, are listed as
organic alkali compounds. For example, as low molecular compounds
are listed monoethanolamine, diethanolamine, trietanolamine,
morpholine, derivatives of them, and alkoxysilane having various
amino groups.
[0056] After the above-mentioned process, a skin is formed on the
surface of the sintered copper alloy material. Particularly, the
film is a paint (or coating) film containing a solid lubricant. As
solid lubricants are listed, for example, PTFE, TPA, graphite,
molybdenum disulfide, tungsten disulfide, boron nitride, tungsten
fluoride, titanium nitride. As paint film binder components are
listed, for example, resins (the thermoplastic resins) such as
polyester, polyolefin, polyurethane, polyacryl, polyamide,
polyimide, epoxy, and silicone. As these paints can be used, for
example, FL-J4668 produced by Nihon Parkerizing Co., Ltd. and EB3
and LHF4B produced by Kawamura Research Laboratories, Inc. A paint
containing the various components mentioned above is applied on the
sintered copper alloy material using the splay method, the dipping
method, the roll coating method, the powder method or the
electro-deposition method and then is baked. Thus, a painted film
having, for example, a thickness of 2 to 20 .mu.m (particularly, 1
to 10 .mu.m) is formed.
[0057] According to the present invention, the sintered copper
alloy is one containing copper. The content of copper is preferably
20 to 95% by weight (is, particularly, 50 to 90% by weight). In
addition, a component, other than Cu is, for example, Zn, Fe, Mn,
Al, Co, P, Mo, Sn, Ni or C. Specifically, the sintered copper alloy
material is B031, B110, B062, or B060.
[0058] Specific embodiments will be described below together with a
comparative example.
Embodiment 1
[0059] Copper alloy powder, which has a grain size of 150 .mu.m or
less, was molded in a predetermined shape under a molding pressure
of 150 to 350 MPa. Thereafter, the molded material was sintered for
40 minutes in an atmosphere of an ammonium decomposition gas at 700
to 900.degree. C. The sintered material was corrected with a sizing
pressure of 100 to 400 MPa.
[0060] First, the sliding parts made of the resultant sintered
copper alloy material B031 (Cu of 85% by weight, Sn of 10% by
weight and C of 5% by weight) was degreased. The degreasing agent
was alkali degreasing agent (FC-315 produced by Nihon Parkerizing
Co., Ltd.). The concentration of the degreasing agent was 20 g/l.
The degreasing temperature was 60.degree. C. The degreasing time
was 2 minutes.
[0061] After degreasing, the sliding parts were rinsed in water.
Thereafter, the sliding parts were dipped in the aqueous solution
containing peroxodisulfate potassium (of a concentration of 5% by
weight) and sulfuric acid (of a concentration of 5% by weight). The
dipping temperature was 27.degree. C. The dipping time was 180
seconds.
[0062] After dipping, the sliding parts were cleaned in running
water.
[0063] Thereafter, FL-J4668 (containing a main constituent of PTFE)
(produced by Nihon Parkerizing Co., Ltd) was sprayed with a spray
gun so as to have a dry thickness of 3 .mu.m. Then, the sprayed
coating was baked at 200.degree. C.
Embodiment 2
[0064] B031-made sliding parts, obtained in a manner similar to
that of the embodiment 1, were used.
[0065] First, the sliding parts were degreased. The degreasing
agent was FC-315. The concentration of the degreasing agent was 20
g/l. The degreasing temperature was 60.degree. C. The degreasing
time was 2 minutes.
[0066] After degreasing, the sliding parts were rinsed in
water.
[0067] Thereafter, the sliding parts were dipped in the aqueous
solution containing peroxophosphoric sodium (of a concentration of
5% by weight) and phosphoric acid (of a concentration of 10% by
weight). The dipping temperature was 27.degree. C. The dipping time
was 180 seconds.
[0068] After dipping, the sliding parts were cleaned in running
water.
[0069] Thereafter, LHF4B (containing a main constituent of PTFE)
(produced by Kawamura Research Laboratories, Inc.) was sprayed with
a spray gun so as to have a dry thickness of 4 .mu.m. Then, the
sprayed coating was baked at 200.degree. C.
Embodiment 3
[0070] B031-made sliding parts, obtained in a manner similar to
that of the embodiment 1, were used.
[0071] First, the sliding parts were degreased. The degreasing
agent, FC-315, was used. The concentration of the degreasing agent
was 20 g/l. The degreasing temperature was 60.degree. C. The
degreasing time was 2 minutes.
[0072] After degreasing, the sliding parts were rinsed in
water.
[0073] Thereafter, the sliding parts were dipped in the aqueous
solution containing chromic acid (of a concentration of 5% by
weight) and hydrogen peroxide (of a concentration of 5% by weight).
The dipping temperature was 27.degree. C. The dipping time was 180
seconds.
[0074] After dipping, the sliding parts were cleaned in running
water.
[0075] Next, the sliding parts were dipped in an aqueous solution
containing phosphoric acid (of 5% by weight) and zinc nitrate (2%
by weight). The dipping temperature was 45.degree. C. The dipping
time was 60 seconds.
[0076] Then, the sliding parts were subjected to ultrasonic
cleaning (25 KHz.times.30 minutes).
[0077] Thereafter, FL-J4668 was sprayed with a spray gun so as to
form a dry thickness of 3 .mu.m. Then, the sprayed coating was
baked at 200.degree. C.
Embodiment 4
[0078] B031-made sliding parts, obtained in a manner similar to
that of the embodiment 1, were used.
[0079] First, the sliding parts were degreased. The degreasing
agent, FC-315, was used. The concentration of the degreasing agent
was 20 g/l. The degreasing temperature was 60.degree. C. The
degreasing time was 2 minutes.
[0080] After degreasing, the sliding parts were rinsed in
water.
[0081] Thereafter, the sliding parts were dipped in an aqueous
solution containing peroxodisulfate potassium (of a concentration
of 5% by weight) and sulfuric acid (of a concentration of 5% by
weight). The dipping temperature was 27.degree. C. The dipping time
was 180 seconds.
[0082] After dipping, the sliding parts were cleaned in running
water.
[0083] Next, the sliding parts were dipped in an aqueous solution
of monoethanolamine (of a concentration of 0.5% by weight) and then
were lift up after a lapse of 15 seconds. Successively, the sliding
parts were dried at 120.degree. C. for 10 seconds.
[0084] Thereafter, FL-J4668 was sprayed with a spray gun so as to
form the dry thickness of 3 .mu.m. Then, the sprayed coating was
baked at 200.degree. C.
Comparative Example 1
[0085] B031-made sliding parts, obtained in a manner similar to
that of the embodiment 1, were used.
[0086] First, the sliding parts were degreased. The degreasing
agent was FC-315. The concentration of the degreasing agent was 20
g/l. The degreasing temperature was 60.degree. C. The degreasing
time was 2 minutes.
[0087] After degreasing, the sliding parts were rinsed in
water.
[0088] Thereafter, the sliding parts were dipped in the aqueous
solution containing hydrochloric acid (of a concentration of 10% by
weight). The dipping temperature was 27.degree. C. The dipping time
was 180 seconds.
[0089] After dipping, the sliding parts were cleaned in running
water.
[0090] Thereafter, FL-J4668 was sprayed with a spray gun so as to
form a dry thickness of 3 .mu.m. Then, the sprayed coating was
baked at 200.degree. C.
Characteristics
[0091] The sliding parts obtained by the above-mentioned
embodiments were inspected in adhesive property, corrosion
resistance and sliding property of a paint film (a lubricating
film). Table 1 shows the results. Moreover, the surface profiles of
the B031 materials after etching process were inspected. Table 1
shows the results.
1 TABLE 1 Paint Film B031 Material Surface Adhesive Corrosion
Sliding Pore size property resistance property Porosity ratio
Embodiment 1 .largecircle. .largecircle. .largecircle. 27.9 15.6
Embodiment 2 .largecircle. .largecircle. .largecircle. 30.6 16.7
Embodiment 3 .largecircle. .largecircle. .largecircle. 25.1 13.4
Embodiment 4 .circleincircle. .largecircle. .circleincircle. 33.5
18.9 Comparative X .DELTA. X 1.4 1.2 Ex. 1
Adhesive Property (Cross-Cut Test)
[0092] A paint film was cut with a cutter knife to form 100
gridirons, each having 1 mm.times.1 mm. Next, an adhesive
cellophane tape is applied onto the paint film and then peeled off.
In this test, symbol {circle over (.smallcircle.)} represents the
case where no skin is peeled off. Symbol .largecircle. represents
the case where one or three pieces of skin are peeled off. Symbol
.DELTA. represents the case where 4 or 20 pieces of skin are peeled
off. Symbol X represents the case where 21 pieces or more of skin
are peeled off.
Corrosion Resistance
[0093] A salt splay test was carried out in conformity with
JIS-K5400. Symbol .largecircle. indicates that there is no sign of
generation of rust. Symbol .DELTA. indicates that there is a sign
of generation of rust. In the case where rust is recognized, the
material is handled as a rejected article.
Sliding Property
[0094] The load (N) until seizure occurs was inspected using the
SRV friction/wear tester. The load to be applied was stepped up at
a rate of 50 N/min. The frequency of vibration is 50 Hz and the
amplitude is 2 mm. Steel balls having a diameter of 10 mm, made of
SUJ-2, were used as the opposite material. The lubricant was not
used. The case where the load of 5000 N is applied is shown by
symbol {circle over (.smallcircle.)}. The case where the load of
4000 to 5000 N or more is applied is shown by symbol .largecircle..
The case where the load of 2000 to 4000 N is applied is shown by
symbol .DELTA.. The case where the load of less than 2000 N is
applied is shown by symbol X.
Porosity
[0095] Porosities were measured in conformity with ISO2738:
Permeable sintered metal materials determination of denst B, oil
content and open porosit B.
Pore Size Ratio
[0096] Pore size ratios were obtained under a microscope and using
a pore quantity device. First, pores having an inlet diameter of 10
to 200 .mu.m were obtained. Next, the corresponding inner pore
diameters were obtained. Average values were obtained by
calculating quotients.
[0097] The above-mentioned result proves that the sintered material
of the present invention excels in the adhesive property of the
film, which is formed on the sintered material through the
selective chemical etching solution process. Furthermore, the
sintered material has a good corrosion resistance and a good
sliding property. That is, even in the case of the comparative
example 1 that carries out the simple etching only but does not
carry out the selective chemical etching, a skin is formed on the
sintered material, in a manner similar to those in the embodiments.
However, the skin is poor in adhesive property, corrosion
resistance, and sliding property.
[0098] According to the present invention, a film of a solid
lubricating agent such as PTFE or molybdenum disulfide can be fixed
firmly and in adhesive state on the sintered material. Good sliding
properties can be obtained under unlubricating conditions or under
corrosive conditions.
* * * * *