U.S. patent application number 12/301907 was filed with the patent office on 2010-02-11 for coating and ion beam mixing apparatus and method to enhance the corrosion resistance of the materials at the elevated temperature using the same.
This patent application is currently assigned to Korea Atomic Energy Research Institute. Invention is credited to Jonghwa Chang, Byungho Choi, Yongwan Kim, Chang-Kue Park, Jaewon Park.
Application Number | 20100032288 12/301907 |
Document ID | / |
Family ID | 38778764 |
Filed Date | 2010-02-11 |
United States Patent
Application |
20100032288 |
Kind Code |
A1 |
Park; Jaewon ; et
al. |
February 11, 2010 |
COATING AND ION BEAM MIXING APPARATUS AND METHOD TO ENHANCE THE
CORROSION RESISTANCE OF THE MATERIALS AT THE ELEVATED TEMPERATURE
USING THE SAME
Abstract
The present invention relates, in general, to shoes for
measuring the quantity of motion and a method of measuring the
quantity of motion using the shoes and, more particularly, to
artificial intelligence shoes, in which various numerical values
(calorie consumption, body fat, and a pulse), measured by a walking
sensor (23), a body fat measurement unit, and a pulse sensor (21)
mounted in a shoe body, are displayed in real time on a display
unit (32), so that a user can periodically check his or her
quantity of motion, and in which calorie consumption and body fat
are calculated on the basis of the user's body conditions, so that
the precision thereof is high, and such quantity of motion
numerical values can be transmitted to various types of external
devices, thus enabling the user to periodically manage the quantity
of motion thereof.
Inventors: |
Park; Jaewon; (Daejeon,
KR) ; Park; Chang-Kue; (Daejeon, KR) ; Chang;
Jonghwa; (Daejeon, KR) ; Choi; Byungho;
(Daejeon, KR) ; Kim; Yongwan; (Daejeon,
KR) |
Correspondence
Address: |
INTELLECTUAL PROPERTY GROUP;FREDRIKSON & BYRON, P.A.
200 SOUTH SIXTH STREET, SUITE 4000
MINNEAPOLIS
MN
55402
US
|
Assignee: |
Korea Atomic Energy Research
Institute
Daejeon
KR
Korea Hydro and Nuclear Power Co., Ltd
Seoul
KR
|
Family ID: |
38778764 |
Appl. No.: |
12/301907 |
Filed: |
October 18, 2006 |
PCT Filed: |
October 18, 2006 |
PCT NO: |
PCT/KR2006/004236 |
371 Date: |
November 21, 2008 |
Current U.S.
Class: |
204/192.11 ;
118/50; 204/298.04; 427/532 |
Current CPC
Class: |
H01J 2237/31701
20130101; H01J 37/317 20130101; C23C 14/48 20130101; C23C 14/5833
20130101; H01J 37/3233 20130101; H01J 2237/316 20130101; H01J
2237/3165 20130101; C23C 14/505 20130101; C23C 14/30 20130101; H01J
2237/3132 20130101; C23C 14/0635 20130101; C23C 14/5893
20130101 |
Class at
Publication: |
204/192.11 ;
118/50; 204/298.04; 427/532 |
International
Class: |
C23C 14/34 20060101
C23C014/34; C23C 14/00 20060101 C23C014/00; B29C 71/04 20060101
B29C071/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 27, 2006 |
KR |
10-2006-0047855 |
Claims
1. A coating and ion beam mixing apparatus comprising an electron
gun 1 disposed in a reaction chamber 10 in a vacuum, a coating
material container 3 located adjacent to the electron gun in the
reaction chamber 10 and irradiated with an electron beam generated
from the electron gun 1, a base material 5 secured in an upper
portion of the reaction chamber 10, one surface of which is coated
with a coating material 4 melted and vaporized in the coating
material container 3, a jig 8 mounted on another surface of the
base material and configured to rotate the base material 5 for
uniform deposition of the coating material 4, and an ion beam
irradiation device 20 mounted on a side wall of the reaction
chamber 10 and configured to mix the coating material 4 with the
base material 5 at an interface therebetween to improve
adhesiveness and compactness of a coating layer.
2. The apparatus according to claim 1, wherein the coating material
is a ceramic material having a high thermal expansion coefficient
and excellent corrosion resistance.
3. The apparatus according to claim 2, wherein the coating material
is at least one of the coating materials selected from the group
consisting of SiC, SiO.sub.2, Al.sub.2O.sub.3 and TiO.sub.2.
4. The apparatus according to claim 1, wherein the coating process
is performed using a physical vapor deposition method including a
sputtering method or an evaporation method.
5. The apparatus according to claim 1, wherein the base material is
a metallic material having excellent mechanical properties at a
temperature ranging from 300 to 900.degree. C.
6. The apparatus according to claim 5, wherein the base material is
at least one selected from the group consisting of Alloy 800H,
Alloy 690, Hastelloy X, Hayness 230, Hayness 556, CX 2002U
composite, Alloy X750, Alloy 718, Sanicro 28 and stainless
steel.
7. The apparatus according to claim 1, wherein, the jig is
configured such that, after a surface of base material is
completely coated, the coated surface of base material is rotated
to face an ion beam irradiation inlet in order to expose the coated
surface of base material to an ion beam radiated from an ion beam
irradiation device.
8. The apparatus according to claim 1, wherein the ion beam
irradiation device 20 comprises: an ion source 21 for generating an
ion; an ion accelerator 22 for accelerating an ion discharged from
the ion source; an acceleration tube 23 for enlarging an
irradiation area of the ion beam; and a gate valve 24 mounted
between the reaction chamber 10 and the ion beam irradiation device
20 to prevent the ion source from being coated with the coating
material.
9. The apparatus according to claim 1, wherein an element used for
the ion beam irradiation depends on a composition of the base
material and a composition of the coating material.
10. (canceled)
11. The apparatus according to claim 9, wherein, the element used
for the ion beam is an element to form compound with elements
constituting the coating and the base materials.
12. The apparatus according to claim 1, wherein an element used for
the ion beam is one selected from the group consisting of carbon,
nitrogen, oxygen, silicon, aluminum, helium, neon, argon titanium,
or the mixture thereof.
13. The apparatus according to claim 1, wherein the processes of
coating and ion beam irradiation are performed one time or several
times in accordance with characteristics of the coating material
and the base material.
14. The apparatus according to claim 13, wherein, in the processes
of coating and ion beam irradiation, as a difference in thermal
properties between the coating material and the base material
increases, the coating is performed more multiple times.
15. The apparatus according to claim 14, wherein, in the case where
the coating is performed several times, the ion beam irradiation is
performed between the coating processes.
16. The apparatus according to claim 1, wherein an energy value and
an injection amount of the ion beam radiated from the ion beam
irradiation device are adjusted depending on a thickness of each
coating layer applied one time or several times.
17. The apparatus according to claim 16, wherein the energy value
of the ion beam ranges from 50 to 500 keV, and the injection amount
of the ion beam ranges from 1.times.10.sup.17 to 1.times.10.sup.18
ions/cm.sup.2.
18. The apparatus according to claim 16, wherein a thickness of
each of the coating layers ranges from 20 to 200 nm.
19. A method of improving adhesiveness and compactness at an
interface between a base material and a coating layer using the
coating and ion beam mixing apparatus according to claim 1,
comprising: melting and vaporizing a coating material by radiating
an electron beam into a coating material container (step 1);
applying the coating material melted and vaporized in step 1 on a
base material (step 2); and radiating an ion beam to mix the
coating material with the base material coated in step 2 at an
interface therebetween (step 3).
Description
TECHNICAL FIELD
[0001] The present invention relates to a ceramic coating and ion
beam mixing apparatus for improving corrosion resistance, and to a
method of modifying an interface between a coating material and a
base material.
BACKGROUND ART
[0002] Recently, according to the so-called green house effect,
which is the result of carbon dioxide discharge, a global warming
phenomenon is rapidly progressing, so that a serious natural
disaster occurs, thereby the existence of human beings is
threatened. Accordingly, human beings have become interested in
hydrogen energy, which does not harm the environment, as a source
of clean energy, and research and development into the clean energy
has been focused on methods of economically producing hydrogen.
[0003] A process for thermochemically producing hydrogen referred
to as an Iodine-Sulfur cycle is considered the most efficient of
the methods of producing hydrogen. In the process, hydrogen is
produced by thermally decomposing sulfuric acid using a
high-temperature gas cooling furnace. The above process has been
considered to be an influential method in that heat is stably
supplied at a temperature of 950.degree. C. or more and
dangerousness is low. However, the selection of the material used
in an apparatus for performing the process is becoming the most
important issue. The reason is that a metal material must be used
for high-temperature elasticity in the apparatus for the hydrogen
producing process, but SO.sub.2 and SO.sub.3, generated at the time
of thermally decomposing sulfuric acid, have extremely high
corrosiveness, and thus it is difficult to establish an economical
system using any metallic material that has been developed to date,
and ceramic materials have excellent corrosion resistance but can
be broken by thermal stress at high temperature, so that it is
difficult to use such ceramic materials in the apparatus for the
hydrogen producing process. Accordingly, a method of coating the
ceramic to a metallic base material having an excellent thermal
property at high temperature has been proposed.
[0004] However, generally, since ceramics and metals are different
from each other in the thermal expansion, the thermal conductivity,
and the like, they have poor adhesiveness with each other and thus
are easily separated. One of the reasons is that, when a metal is
exposed to an atmosphere with a high temperature, an oxide film is
easily formed on the surface thereof, so that, when the metal is
coated with different materials, the oxide film decreases
adhesiveness therebetween.
[0005] While the present inventors researched methods of increasing
adhesiveness between a metal base material and a ceramic thin film
and maintaining high adhesiveness even at high temperature, they
found that, when the ceramic is mixed with the metal materials at
an interface therebetween using a so-called ion beam mixing method,
which is a method of coating a metal base material with a ceramic
thin film and then mixing the two different materials by radiating
an ion beam, the adhesiveness is increased, and when a ceramic thin
film is further applied to the mixed layer, the adhesiveness is
maintained even at high temperatures, and the corrosion resistance
at a high temperature is improved. As the result of the findings,
the present inventors completed the present invention.
DISCLOSURE
Technical Problem
[0006] An object of the present invention is to provide a coating
and ion beam mixing apparatus, which can perform a process of
coating and ion beam mixing in a single reaction chamber to improve
the adhesion at the interface between a metal base material and a
ceramic coating layer.
[0007] Another object of the present invention is to provide a
method of improving the adhesion at the interface between a metal
base material and a coating layer using the coating and ion beam
mixing apparatus.
Technical Solution
[0008] In order to accomplish the above objects, the present
invention provides a coating and ion beam mixing apparatus
including, an electron gun 1 disposed in a reaction chamber 10 in a
vacuum, a ceramic coating material container 3 located adjacent to
the electron gun and irradiated with an electron beam generated
from the electron gun 1, a metallic base material 5 fixed in an
upper portion of the reaction chamber 10, one surface of which is
coated with the coating material 4 melted and vaporized in the
coating material container 3, a jig 8 mounted on the other surface
of the base material and configured to rotate the base material 5
for homogenous deposition of the coating material 4, and an ion
beam irradiation device 20 mounted on a side wall of the reaction
chamber 10 and configured to mix the coating material 4 with the
base material 5 at the interface therebetween to improve the
adhesion of a coating layer.
[0009] Further, the present invention provides a method of
improving the adhesion at the interface between a metallic base
material and a ceramic coating layer using the coating and ion beam
mixing apparatus, including melting and vaporizing the ceramic
coating material by radiating an electron beam into a coating
material container (step 1), applying the coating material, melted
and vaporized in step 1, on a base material (step 2), and radiating
an ion beam to mix the coating material with the base material
coated in step 2 at the interface therebetween (step 3).
ADVANTAGEOUS EFFECTS
[0010] As described above, in the samples fabricated using the
ceramic coating and ion beam mixing apparatus according to the
present invention, the adhesion is improved, and the metallic base
material is reinforced, thereby improving resistance to the thermal
stresses at high temperatures and the high-temperature corrosion
resistance of a material to be used in a sulfuric acid
decomposition apparatus for producing hydrogen.
DESCRIPTION OF DRAWINGS
[0011] FIG. 1 is a view elucidating the general idea of coating and
ion beam mixing according to the present invention.
[0012] FIG. 2 is a schematic view of a coating and ion beam mixing
apparatus according to an embodiment of the present invention.
[0013] FIG. 3 is a schematic view of an ion beam irradiation device
according to an embodiment of the present invention.
[0014] FIG. 4 is a graph showing the result of an auger depth
profiling with respect to a SiC thin film deposited on the surface
of Inconel according to an embodiment of the present invention.
[0015] FIG. 5 is a view showing the surface contour of a sample
that has been thin-coated by radiating an ion beam after corrosion
of the sample according to an embodiment of the present
invention.
[0016] FIG. 6 is a view showing the surface contour of a sample
that has been thin-coated by radiating an ion beam after the
electrolytic etching of the sample according to an embodiment of
the present invention.
[0017] FIG. 7 is a photograph showing the surface contour of a
sample that has been thin-coated without radiating an ion beam
after the sample is heated according to an embodiment of the
present invention.
[0018] FIG. 8 is a photograph showing the surface contour of a
sample that has been thin-coated by radiating an ion beam after the
sample has been heated according to an embodiment of the present
invention.
[0019] FIG. 9 is a photograph showing a surface contour of a sample
that has been thin-coated by radiating an ion beam after the
heating and electrolytic etching of the sample according to an
embodiment of the present invention.
[0020] FIG. 10 is a photograph showing a surface contour of a
sample that has been thin-coated by radiating an ion beam after the
additional thin-coating, heating and electrolytic etching of the
sample according to an embodiment of the present invention.
DESCRIPTION OF THE ELEMENTS IN THE DRAWINGS
[0021] 1: electron gun [0022] 2: electron beam [0023] 3: ceramic
container [0024] 4: melted and vaporized ceramic [0025] 5: base
material [0026] 5': base material rotated to face ion beam
irradiation inlet [0027] 6: ion beam irradiation inlet [0028] 8:
jig [0029] 10: reaction chamber [0030] 20: ion beam irradiation
device [0031] 21: ion source [0032] 22: ion beam accelerator [0033]
23: acceleration tube [0034] 24: gate valve
BEST MODE
[0035] Hereinafter, the present invention will be described with
reference to the accompanying drawings.
[0036] FIG. 1 is a view elucidating the general idea of coating and
ion beam mixing according to the present invention.
[0037] As shown in FIG. 1, when a thin coating layer is primarily
formed on a base material and then an ion beam is radiated on the
coating layer, ions collide with the coating layer, and thus energy
is applied to the atoms of the coating layer, with the result that
the atoms of the coating layer are pushed and simultaneously
injected into the base material, and thus an ion beam mixing
phenomenon occurs, thereby mixing the coating layer with the base
material at the interface therebetween. Accordingly, the stress of
the thin film is decreased and a new mixed layer is formed at the
interface, thereby improving the sustainability of the thin film.
Further, when a coating layer is additionally formed on the mixed
layer, the coating layer is not easily peeled off from the base
material because the coating layer is strongly adhered at the
interface.
[0038] The term "ion beam mixing" used in the specification refers
to a phenomenon whereby atoms of a coating material collide with an
ion beam radiated thereto when ionized atoms having high energy
collide with the surface of the coating material, and atoms of the
coating material are then recoil-implanted. For this reason, the
coating layer is mixed with the base material at the interface
therebetween.
[0039] Variables pertinent to the ion beam mixing may include the
coating material, the energy of the ion beam, and the quantity of
ions injected. In the apparatus and method of the present
invention, optimal conditions are provided by combining the
variables.
[0040] FIG. 2 is a schematic view of a coating and ion beam mixing
apparatus according to an embodiment of the present invention.
[0041] As shown in FIG. 2, the coating and ion beam mixing
apparatus according to an embodiment of the present invention may
include an electron gun 1 disposed in a reaction chamber 10 in a
vacuum, a coating material container 3 located adjacent to the
electron gun in the reaction chamber 10 and irradiated with an
electron beam generated from the electron gun 1, a metallic base
material 5 secured in an upper portion of the reaction chamber 10,
one surface of which is coated with a ceramic coating material 4
melted and vaporized in the coating material container 3, a jig 8
mounted on the other surface of the base material and configured to
rotate the base material 5 to uniformly deposit the coating
material 4, and an ion beam irradiation device 20 mounted on a side
wall of the reaction chamber 10 and configured to mix the coating
material 4 with the base material 5 at the interface therebetween
to improve the adhesiveness and compactness of a coating layer.
[0042] In the coating and ion beam mixing apparatus according to an
embodiment of the present invention, it is preferred that the
coating process and ion injection process be performed in one
reaction chamber 10 in a vacuum.
[0043] Generally, when a metal material is exposed to the
atmosphere, an oxide film is easily formed on the surface thereof.
When the oxide film is coated with different materials, the oxide
film decreases adhesiveness therebetween. Accordingly, it is
preferred that the reaction chamber be in a vacuum state. Further,
when the coating process and an ion beam process are independently
performed in different reaction chambers in a vacuum, extraneous
materials are attached to the coating layer during the movement of
the sample, and this phenomenon is not preferable. Accordingly, it
is preferred that the coating process and ion beam irradiation
process be performed in a single reaction chamber in a vacuum in
order to efficiently perform the processes.
[0044] In the coating and ion beam mixing apparatus according to an
embodiment of the present invention, a ceramic material having a
high thermal expansion coefficient and excellent corrosion
resistance may be used as a coating material 4. In this case, it is
preferred that SiC, SiO.sub.2, Al.sub.2O.sub.3, TiO.sub.2, etc. be
used as the coating materials 4.
[0045] In the coating and ion beam mixing apparatus according to an
embodiment of the present invention, the coating process may be
performed using a physical vapor deposition method including a
sputtering method or an evaporation method in order to apply a
coating material on a base material 5.
[0046] The coating method may be performed using a Physical Vapor
Deposition (PVD) method and a Chemical Vapor Deposition (CVD)
method. The difference between the two methods may be the
difference in process temperature. Specifically, in the physical
vapor deposition method, the coating process can be performed at a
process temperature of several hundreds of degrees C. or lower. In
contrast, the chemical vapor deposition method is a coating method
performed at a process temperature of about 1000.degree. C.
However, the coating method of the present invention is performed
to apply the coating material on a base material 5. When the
coating method of the present invention is performed using heat at
a temperature as high as about 100.degree. C., the characteristics
of the base material can change, therefore it is preferred that the
coating process be performed using the physical vapor deposition
method.
[0047] The physical vapor deposition method is a coating method in
which a coating material is converted into gas and the gaseous
material is then deposited, and includes a sputtering method or an
evaporation method. Ultimately, there is no great difference in the
characteristics of the surface modified base material resulting
from the mixing process regardless of which of these methods is
used. The sputtering method has an advantage in that a large coated
area is easily performed if the target surface of a material for
coating is large. In contrast, the evaporation method has an
advantage in that it is possible to coat a large area using a small
amount of material. The kinetic energy of coating atoms is higher
in the sputtering method than in the evaporation method, therefore
the sputtering method has an advantage in that a relatively compact
coating layer is formed. However, if an ion beam is radiated after
the coating process is completed, this difference is almost
overcome, and thus the evaporation method can be advantageous.
However, it is apparent in the related arts that either of the two
methods can be selected as necessary.
[0048] Moreover, in the coating and ion beam mixing apparatus
according to an embodiment of the present invention, a metallic
material having excellent mechanical properties at a temperature
ranging from 300 to 900.degree. C. may be used as a base material.
In this case, Alloy 800H, Alloy 690, Hastelloy X, Hayness 230,
Hayness 556, CX 2002U composite, Alloy X750, Alloy 718, Sanicro 28
or stainless steel may be used as the base material.
[0049] Further, the coating and ion beam mixing apparatus according
to an embodiment of the present invention may include the jig 8
configured to be rotated, so that the coated surface of the base
material 5 faces an ion beam irradiation inlet 6 thereby being
exposed to an ion beam radiated from the ion beam irradiation
device 20, after the surface of the base material 5 is completely
coated.
[0050] Since the surface of a coating layer is made to face an ion
beam irradiation inlet 6 by tilting the jig 8 holding the base
material by a predetermined angle (see 5' in FIG. 1), the mixing
process can be efficiently performed when the ion beam 7 is
radiated on the surface of the coating layer.
[0051] FIG. 3 is a schematic view of an ion beam irradiation device
20 according to an embodiment of the present invention.
[0052] As shown in FIG. 3, the coating and ion beam mixing
apparatus according to an embodiment of the present invention may
include the ion beam irradiation device 20 including an ion source
21 for generating an ion, an ion accelerator 22 for accelerating an
ion discharged from the ion source 21, an acceleration tube 23 for
enlarging the irradiation area of the ion beam, and a gate valve 24
mounted between the reaction chamber 10 and the ion beam
irradiation device 20 to prevent the ion source 21 from being
coated with the coating material.
[0053] In the coating and ion beam mixing apparatus according to an
embodiment of the present invention, the element used in the ion
beam irradiation device 20 depends on the difference between the
composition of the base material 5 and the composition of the
coating material 4.
[0054] In the case where the composition of the base material 5 is
identical with the composition of the coating material 4, the
element used in the ion beam irradiation device 20 may be
independently selected from all elements in nature, or may be a
mixture of the elements.
[0055] In contrast, in the case where the composition of the base
material 5 is different from the composition of the coating
material 4, the element used in the ion beam irradiation device 20
may be an element having a relatively small composition ratio among
elements constituting the coating material 4. For example, in the
case where the coating process uses SiC, the coating process is
frequently performed using SiC.sub.1-x(X<<1), wherein the
number of carbon atom is insufficient. Accordingly, in this case,
if the carbon atom is used as an ion source 21 and is radiated on
the coating material, the composition of the thin film can be
complemented, and an ion beam mixing effect can be realized.
[0056] In the coating and ion beam mixing apparatus according to an
embodiment of the present invention, it is preferred that carbon,
nitrogen, oxygen, silicon, aluminum, helium, neon, argon, and
titanium, or a mixture thereof be the element used in the ion beam
irradiation device 20.
[0057] In the coating and ion beam mixing apparatus according to an
embodiment of the present invention, the processes of coating and
ion beam mixing may be performed by performing the coating and ion
beam irradiation one time or several times in accordance with the
characteristics of the coating material 4 and the base material
5.
[0058] In this case, in the processes of coating and ion beam
irradiation, the coating may be performed several times as the
difference in the thermal properties between the coating material 4
and the base material 5 increases. In this case, in the case where
the coating is performed several times, the ion beam irradiation
may be performed between the coating processes.
[0059] In the coating and ion beam mixing apparatus according to an
embodiment of the present invention, the energy value and injection
amount of the ion beam radiated from the ion beam irradiation
device are adjusted depending on the thickness of each coating
layer, coated one time or several times, thereby performing the
process of coating and ion beam mixing.
[0060] In this case, it is preferred that the energy value of the
ion beam range from 50 to 500 keV, and that the injection amount of
the ion beam range from 1.times.10.sup.17 to 1.times.10.sup.18
ions/cm.sup.2. Moreover, it is preferred that the thickness of each
of the coating layers range from 20 to 200 nm.
[0061] Further, the present invention provides a method of
improving an adhesion at the interface between a base material and
a coating layer using the coating and ion beam mixing apparatus,
including melting and vaporizing a coating material by radiating an
electron beam into a coating material container (step 1), applying
the coating material, melted and vaporized in step 1, on a base
material (step 2), and radiating an ion beam to mix the coating
material with the base material coated in step 2 at the interface
therebetween (step 3).
[0062] In this case, the method of improving an adhesion at the
interface between a base material and a coating layer using the
coating and ion beam mixing apparatus may include a method of
performing the most preferable among the coating methods and an
interface mixing by efficiently combining the coating with the ion
beam irradiation.
[0063] Hereinafter, each of the steps will be described in
detail.
[0064] First, step 1 is a step of melting and vaporizing a coating
material by radiating an electron beam into a coating material
container.
[0065] In step 1, a material for coating is put into a coating
material container 30 provided in the coating and ion beam mixing
apparatus, an electron beam 2 is radiated from an electron gun
located adjacent to the coating material container 3, the electron
beam 2 is warped by a magnetic field applied thereto and thus
reaches the center of the coating material container 3, a coating
material 4 is melted and vaporized, and then the vapors of the
coating material 4 reach the surface of a metal base material 5
secured to the upper portion of a reaction chamber, thereby coating
the metal base material 5 with the vaporized coating material
4.
[0066] In this case, the coating material 4 may be selected from
ceramic materials including SiC, TiO.sub.2, Al.sub.2O.sub.3, and
the like.
[0067] Next, step 2 is a step of applying the coating material
melted and vaporized in step 1 on a base material.
[0068] In this case, the jig 8 is provided on the surface of the
base material 5 and the base material 5 is rotated during a
deposition process in order to uniformly deposit the coating
material 4 on the base material 5. The base material 5 can be
deposited to a predetermined thickness due to the rotation
thereof.
[0069] The base material 5 may be selected from the group
consisting of Alloy 800H, Alloy 690, Hastelloy X, Hayness 230,
Hayness 556, CX 2002U composite, Alloy X750, Alloy 718, Sanicro 28,
or stainless steel.
[0070] Next, step 3 is a step of radiating an ion beam to mix the
coating material with the base material coated in step 2 at the
interface therebetween.
[0071] After the base material 5 is deposited to a predetermined
thickness, the surface of the coating layer is made to face the ion
beam irradiation inlet 6 by orienting the jig 8 holding the base
material at a predetermined angle (see 5' in FIG. 1). The mixing
process can be efficiently performed when the ion beam 7 is
radiated on the surface of the faced coating layer.
[0072] All elements in nature may be used as the ion source 21 of
the ion beam. However, since a ceramic material is generally formed
of two or more elements, the composition of the coating layer can
be different from that of the original ceramic material when the
coating process is performed using the above mentioned deposition
methods. In order to solve this problem, a specific element may be
selected. For example, in the case where the coating process uses
SiC, the coating process is frequently performed using SiC.sub.1-x
(X<<1), wherein the number of carbon atoms is small.
Accordingly, in this case, if carbon atoms are used as the ion
source 21 and are radiated on the coating material, the composition
of the thin film can be complemented and ion beam mixing effect can
be realized. In contrast, in the case where the composition of the
coating layer is identical with the composition of an original
ceramic coating material, any element may be used as the ion source
21, but nitrogen atom may be used as the ion source 21 to improve
the characteristics of the base material 5 which is in contact with
an interface. Moreover, the element used as the ion source 21 may
be independently used, or may be used by mixing these elements.
[0073] In this case, it is preferred that the energy value of the
ion beam range from 50 to 500 keV, and that the injection amount of
the ion beam range from 1.times.10.sup.17 to 1.times.10.sup.18
ions/cm.sup.2. Moreover, it is preferred that the thickness of each
of the coating layers range from 20 to 200 nm. When the injection
amount of the ion beam is 1.times.10.sup.17 ions/cm.sup.2 or less,
it is disadvantageous with respect to efficiency because the degree
of mixing is low. In contrast, when the injection amount of the ion
beam is 1.times.10.sup.18 ions/cm.sup.2 or more, the thin film in
the coating process can be damaged by etching.
[0074] The method of improving adhesiveness and compactness at the
interface between a base material and a coating layer using the
coating and ion beam mixing apparatus may include a method of
performing the more preferable of coating and interface mixing by
efficiently combining coating with ion beam irradiation.
[0075] In the method of improving adhesiveness and compactness at
the interface between a base material and a coating layer according
to the present invention, it is preferred that the high-temperature
thermal properties of the base material 5 and the coating material
4, which are finally selected, be similar to each other. For
example, when SiC is selected as the coating material, Hastelloy X
is most advantageously used as the base material 5. The reason is
that the thermal properties of SiC and Hastelloy X, considering the
thermal expansion coefficient and the elastic coefficient, are more
similar to each other than the other materials combination, thermal
stresses exerting at the interface therebetween is relatively low,
and thus the likelihood of the peeling phenomenon is relatively
low. However, when heat or external stress is applied between two
different materials, the two different materials are easily
separated from each other. Accordingly it is necessary to make the
sharp interface therebetween dull. This problem can be overcome
using a method including the steps of forming a primary thin
coating and then mixing the two materials by radiating an ion beam
7, forming a secondary coating, further mixing the two materials
with the layer mixed with the primary coating layer by further
radiating an ion beam 7, and performing additional coating.
[0076] If necessary, the process of coating and ion beam
irradiation may be repeatedly performed several times. In this
case, the thickness of the coating layer can be adjusted in
consideration of the characteristics of the ion beam energy and the
base material 5. For example, the depth to which the element of the
coating material is injected to the base material again due to the
repulsion after collision with the ion beam irradiation is
proportional to the energy of the ion. When the energy of the ion
is constant, it is preferred that the thin film be thin,
considering that the coating material is mixed with the base
material 5. Accordingly, it is most preferable that the ion beam
irradiation be performed between a coating process and a subsequent
coating process, while the coating processes are performed several
times. As a result, the two different materials are less sensitive
to external stress because they have more properties in common at
the interface therebetween.
[0077] Specifically, the ion beam generated from the ion source,
such as argon, carbon, nitrogen or oxygen, which have energy of 50
to 500 keV, may be selectively radiated in accordance with the
characteristics of the coating material and base material. The
energy of the injected ion beam may be adjusted in accordance with
the final thickness of the coating layer, and, when the coating
process is performed several times, the thickness of each of the
coating layers. However, when the coating layer is excessively
thick, the mixing process using the ion irradiation may be
impossible on the interface because the ion range may be within the
coating layer. Therefore, it is preferred that the energy be
adjusted such that it has a high energy state. In contrast, when
the energy of the ion beam is low, the thickness of the coating
layer must also be decreased. Generally, as the energy of the
radiated ion beam is high or the amount of the radiated ion beam is
large, the efficiency of mixing is increased. However, when the
amount of the radiated ion beam is excessively large, the coating
layer etc. is damaged due to the ion beam irradiation, and thus the
opposite effect is produced, and the working cost is also
increased, therefore it is preferred that the energy of the ion
beam be adjusted to exhibit preferable physical properties and
incur a suitable working cost. Accordingly, it is preferred that
the injection amount of the ion beam range from 1.times.10.sup.17
to 1.times.10.sup.18 ions/cm.sup.2. When the injection amount of
the ion beam is 1.times.10.sup.17 ions/cm.sup.2 or less, this is
advantageous with respect to efficiency, because the degree of
mixing is low. In contrast, when the injection amount of the ion
beam is above 1.times.10.sup.18 ions/cm.sup.2, a thin film in the
coating process can be damaged by etching.
MODE FOR INVENTION
[0078] Hereinafter, the present invention will be described in
detail based on Examples. However, the following Examples merely
illustrate the present invention, and the present invention is not
limited to the following Examples.
Example 1
Analysis of SiC Thin Film Coated Using an Ion Beam Deposition
Method
[0079] An SiC thin film was melted and vaporized and was then
deposited on Inconel 690 by applying an electric power of 10 kW
using an electron beam evaporative deposition method, and then
Auger depth profiling was performed. The results of the Auger depth
profiling are shown in FIG. 4.
[0080] As shown in FIG. 4, the SiC thin film was deposited on the
surface of the Inconel 690, but the surface of the SiC thin film is
covered with SiO.sub.2, because the SiO.sub.2 is easily formed,
compared to the SiC. Therefore, difficulties in process control are
likely to arise, because the coating process and the ion beam
irradiation process are respectively performed in different
reaction chambers, and it has been found that the coating process
and the ion beam irradiation process must be performed in a single
reaction chamber.
Experimental Example 1
Experiment on Change in Resistance of Thin Film to Sulfuric Acid
Solution Corrosion by Ion Beam Irradiation
[0081] Inconel 680H samples were cut to a size of 20 mm.times.20
mm.times.5 mm, the entire surfaces thereof were polished to an
average surface roughness (Ra) of 50 nm or less, and then SiC was
deposited thereon. Next, the samples were put into a sulfuric acid
solution having a concentration of 50% at 300.degree. C., and then
were corroded for 1 hour, in a state in which test samples were
irradiated with an ion beam, and the other samples were not
irradiated with an ion beam. After 1 hour had passed, the surface
contours of the samples were observed. The results thereof are
shown in FIG. 5.
[0082] As shown in FIG. 5, a thin film remains on the surface of
the sample irradiated with an ion beam, but the thin film is almost
peeled off of the surface of the sample not irradiated with the ion
beam. The colors of the surface of sample appear to be different
due to the difference in the thickness of the thin film. Even
though the thickness is not uniform, the effect of ion beam
irradiation is apparent.
[0083] Accordingly, it was found that, when the thin film is
irradiated with the ion beam, the corrosion resistance thereof is
improved.
Experimental Example 2
Experiment on Changes in Resistance to Electrical Etching of Thin
Film Due to Ion Beam Irradiation
[0084] A circular SiC thin film having a diameter of 20 mm was
deposited on the surface of Hastelloy X, which has a size of 20
mm.times.20 mm.times.5 mm and is polished to a surface roughness of
50 nm or less. Next, in the state in which testing samples were
irradiated with an ion beam, and the other samples were not
irradiated with the ion beam, the thin film reaches the surface of
a material not coated with electrodes, and was electrolytically
etched by applying a voltage of 4 V and a current of 0.4 A. After
the thin film was etched, the surface contours of the samples were
observed. The results thereof are shown in FIG. 6.
[0085] As shown in FIG. 6, in the sample not irradiated with the
ion beam, a peeling phenomenon in the shape of flakes occurred at
the corners of the coating layer of the sample. However, in the
sample irradiated with an ion beam, the thin film was spread and
the peeling phenomenon in the shape of flakes was not observed.
Meanwhile, in the sample irradiated with an ion beam, it was found
that the corrosion resistance of the base material located beneath
the thin film was improved due to the effect of ion beam
irradiation or ion beam mixing.
Experimental Example 3
Auger Si Mapping at the Interface Between a Sic Thin Film and a
Base Material Before and after Ar Ion Beam Irradiation
[0086] When an Ar ion beam is radiated on a thin film, the
following experiment was performed using auger mapping to detect
the mixing phenomenon at the interface between the thin film and
the base material.
[0087] A circular SiC thin film having a diameter of 20 mm was
deposited on the surface of Hastelloy X, which has a size of 20
mm.times.20 mm.times.5 mm and is polished to a surface roughness of
50 nm or less. Next, comparison samples were not irradiated with an
Ar ion beam, and testing samples were irradiated with an Ar ion
beam. Then, an element distribution in the interface was mapped
using the auger mapping. The results thereof are shown in FIGS. 7
and 8.
[0088] FIG. 7 is a photograph of the mapping of the Si element
distribution at the interface of a sample coated only with SiC
without the Ar ion beam radiated. In the photograph, the part in
which the Si element exists is indicated in white, and the other
part, which is a base material, in which there is no Si element, is
indicated in black. As shown in FIG. 7, in the sample coated only
with SiC, the Si element does not appear to have infiltrated into
the base material.
[0089] Meanwhile, FIG. 8 is a photograph mapping the Si element
distribution at the interface of a sample irradiated with an Ar ion
beam after coating with SiC. As shown in FIG. 8, in the sample
irradiated with an Ar ion beam after the coating of SiC, since the
Si element, which is indicated in white, is spread toward the base
material, the mixing process is determined to have occurred. Since
the Si is contained in SiC, it has been found that a SiC coating
layer is mixed well with the base material due to the above
results.
Experimental Example 4
Experiment on Variation in the Thin Film Deterioration by
Heating
[0090] A circular SiC thin film having a diameter of 20 mm was
deposited on the surface of Hastelloy X, which has a size of 20
mm.times.20 mm.times.5 mm and is polished to a surface roughness of
50 nm or less. Next, the thin film was heated in an atmosphere of
900.degree. C. for 1 hour in a state in which testing samples were
irradiated with an ion beam, and the other samples were not
irradiated with an ion beam. After 1 hour had passed, the surface
contours of the samples were observed. The results thereof are
shown in FIGS. 9 and 10.
[0091] Almost no peeling phenomenon occurred in the sample
irradiated with an ion beam (see FIG. 9), but the peeling
phenomenon occurred to a large extent in the sample irradiated with
an ion beam (see FIG. 10). The colors of the sample are changed
because the surface of the sample is oxidized. In the sample
irradiated with an ion beam, the thin film spread at the corners of
the sample.
Experimental Example 5
Electrolytic Etching Experimentation of the SiC Thin Film Coated on
Hastelloy X not Irradiated with an Ion Beam
[0092] A circular SiC thin film having a diameter of 20 mm was
deposited on the surface of Hastelloy X, which has a size of 20
mm.times.20 mm.times.5 mm and is polished to a surface roughness of
50 nm or less, to a thickness of 550 nm. Next, the thin film was
heated to 900.degree. C. for 1 hour and then part of the thin film
was electrolytically etched. After the thin film was etched, the
surface contours of the samples were observed using an optical
microscope. The results thereof are shown in FIG. 11.
[0093] As shown in FIG. 11, the portion that peeled off from the
coated portion by thermal stress was etched. The portion that was
etched is readily distinguishable from the portion that was not
etched.
Experimental Example 6
Electrolytic Etching Experiment of the SiC Thin Film Coated on
Hastelloy X and Irradiated with an Ion Beam
[0094] A circular SiC thin film having a diameter of 20 mm was
deposited on the surface of Hastelloy X, which has a size of 20
mm.times.20 mm.times.5 mm and is polished to a surface roughness of
50 nm or less, to a thickness of 50 nm, a nitrogen ion beam of 70
keV was then radiated thereon, and then additional deposition was
conducted to a thickness of 500 nm. Next, as in Experimental
Example 5, the thin film was heated at 900.degree. C. for 1 hour
and then part of the thin film was electrolytically etched. After
the thin film was etched, the surface contours of the samples were
observed using an optical microscope. The results thereof are shown
in FIG. 12.
[0095] As shown in FIG. 12, the etched portion is almost
indistinguishable from the unetched portion, because the partially
peeled portion was not well etched either.
[0096] Accordingly, when the coating process and the ion beam
irradiation process are repeatedly performed, the corrosion
resistance can be greatly improved.
INDUSTRIAL APPLICABILITY
[0097] In the samples fabricated using the coating and ion beam
mixing apparatus, the adhesiveness is improved, and the base
material is reinforced, so that the resistance to the thermal
stresses at high temperatures and the corrosion-resistance at high
temperatures can be improved, therefore the samples can be usefully
used in a sulfuric acid decomposition apparatus for producing
hydrogen.
* * * * *