U.S. patent application number 12/527003 was filed with the patent office on 2010-05-06 for pb-free copper-based sintered sliding material.
This patent application is currently assigned to TAIHO KOGYO CO., LTD.. Invention is credited to Takashi Tomikawa, Hitoshi Wada, Daisuke Yoshitome.
Application Number | 20100111753 12/527003 |
Document ID | / |
Family ID | 39690068 |
Filed Date | 2010-05-06 |
United States Patent
Application |
20100111753 |
Kind Code |
A1 |
Yoshitome; Daisuke ; et
al. |
May 6, 2010 |
Pb-FREE COPPER-BASED SINTERED SLIDING MATERIAL
Abstract
[Task] The adhesion resistance of Cu--Bi based or Cu--Sn--Bi
based alloy is lower than that of Cu--Sn--Pb based alloy, and also
since conformability of the former alloy is low. Therefore, when Bi
of the former alloy adheres onto an opposite shaft, seizure of the
former alloy is likely to occur as compared with the case of the
latter Cu--Sn--Pb based alloy. In is alloyed in the Bi phase of the
Cu--Sn--Bi--In based copper alloy. The In-alloyed Bi phase has a
considerably low melting point and therefore the sliding properties
deteriorate. [Means for Solving] A Pb-free copper-based sintered
sliding material has a composition that 0.5 to 15.0 mass % Bi and
0.3 to 15.0 mass % In, with the balance being Cu and inevitable
impurities. With regard to the existence of Cu, Bi, and In, the
material consists of a Cu matrix containing In, a Bi phase, and an
In concentrated region in said Cu matrix at a boundary of said Bi
phase.
Inventors: |
Yoshitome; Daisuke;
(Toyota-shi, JP) ; Tomikawa; Takashi; (Toyota-shi,
JP) ; Wada; Hitoshi; (Toyota-shi, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
TAIHO KOGYO CO., LTD.
Toyota-shi
JP
|
Family ID: |
39690068 |
Appl. No.: |
12/527003 |
Filed: |
February 13, 2008 |
PCT Filed: |
February 13, 2008 |
PCT NO: |
PCT/JP2008/052320 |
371 Date: |
October 6, 2009 |
Current U.S.
Class: |
420/470 ;
420/489; 420/499 |
Current CPC
Class: |
B22F 2998/10 20130101;
C22C 32/0089 20130101; B22F 2998/10 20130101; C22C 1/0425 20130101;
F16C 2204/18 20130101; C22C 9/02 20130101; B22F 3/1007 20130101;
B22F 3/1007 20130101; B22F 3/115 20130101; B22F 2201/013 20130101;
B22F 3/18 20130101; C22C 9/06 20130101; C22C 9/00 20130101; F16C
33/121 20130101; B22F 2998/10 20130101 |
Class at
Publication: |
420/470 ;
420/489; 420/499 |
International
Class: |
C22C 9/00 20060101
C22C009/00; C22C 9/02 20060101 C22C009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 14, 2007 |
JP |
2007-032896 |
Claims
1. A Pb-free copper-based sintered sliding material containing 0.5
to 15.0 mass % Bi and 0.3 to 15.0 mass % In, with the balance being
Cu and inevitable impurities, characterized by the existence of Cu,
Bi, and In in the material as follows, namely, a Cu matrix
containing In, a Bi phase, and an In concentrated region in said Cu
matrix at a boundary of said Bi phase.
2. A Pb-free copper-based sintered sliding material according to
claim 1, characterized in that said material further contains 0.5
to 15.0 mass % Sn, and the total content of In+Sn is 1.0 to 15.0
mass %.
3. A Pb-free copper-based sintered sliding material according to
claim 1 or 2, characterized in that said material further contains
0.5 mass % or less P and 0.1 to 5.0 mass % Ni.
4. A Pb-free copper-based sintered sliding material according to
claim 1, characterized in that hard particles of an
iron-based-compound, such as Fe.sub.2P, Fe.sub.3P, FeB, Fe.sub.2B,
and Fe.sub.3B, is contained in an amount of 0.1 to 10.0 mass %
relative to 100 mass % of said iron-based sintered sliding
material.
5. A Pb-free copper-based sintered sliding material according to
claim 1, characterized in that a solid lubricant is contained in an
amount of 5.0 mass % or less relative to 100 mass % of said
iron-base sintered sliding material.
Description
TECHNICAL FIELD
[0001] The present invention relates to a copper-based sliding
material, more particularly, to a copper-based sliding material
having improved sliding properties notwithstanding inclusion of
Pb.
BACKGROUND TECHNIQUE
[0002] Sliding material is required to support a load. In the case
of copper alloy, this function is performed by Cu. Meanwhile, Pb is
usually added to a copper alloy. Such Pb is present on the sliding
surface of copper alloy elongates due to rise in temperature during
sliding. Pb exhibits excellent self lubricating property and plays
a role of solid lubricant to prevent seizure. In addition, since Pb
forms a soft dispersion phase, it has conformability and allows
solid matter to be embedded therein. However, Pb is of great
concern because of its harmful effect to the human body and
environment. In addition, Pb is liable to be corroded by acid
except sulfuric acid. Coarse lead particles present in Cu alloy
lower the load resistance of a bearing. Therefore, Patent Document
1 (Japanese Examined Patent Publication (kokoku) Hei 8-19945)
proposes a specific calculation equation, which determines
distribution of fine particles. This equation is obtained by
counting total Pb particles in a view field of 0.1 mm.sup.2
(10.sup.5 .mu.m.sup.2), and calculating their area in percentage.
The obtained value is processed to % average area per particle,
which should be 0.1% or less.
[0003] It is known from Patent Document 2 (Japanese Examined Patent
Publication (kokoku) No. 7-9046) that such carbide hard-particle
additives as Cr.sub.2C.sub.3, Mo.sub.2C, WC, VC, and NbC in
sintered copper alloy enhance its wear resistance. According to
this publication, a copper-alloy powder having an average particle
diameter of 10 to 100 .mu.m and a hard-particle powder having an
average particle-diameter of 5 to 150 .mu.m are mixed with a V-type
blender, and then compacted and sintered. It discloses that Pb is
present in the grain boundaries of copper particles (column 4,
lines 21-22). This finding is in agreement with a knowledge derived
from a phase diagram showing the fact that Pb is virtually not
dissolved in solid Cu.
[0004] It is known from Patent Document 3 (Japanese Unexamined
Patent Publication (kokai) No. 10-330868) that a Pb-free Cu--Bi
based alloy attains sliding properties equivalent to those of a
Cu--Pb based sintered alloy. In the former alloy, a Bi (alloy)
phase is present in the three-pronged junctions and their
vicinities in the grain boundaries. Patent Document 3 discloses 5
to 50 mass % of Bi phase consisting of Bi or Bi-based alloy. The Bi
phase contains at least element of Sn, Ag, or In, in particular,
20% by weight or less Sn, 10% by weight or less Ag, and 5% by
weight or less In. According to an exemplary manufacturing method,
a pure Bi powder or Bi powder containing at least one of Sn, Ag,
and Bi is mixed with any one of pure Cu powder, bronze powder, and
phosphor bronze powder, and the resulting mixture is compressed and
sintered. Sintering conditions include 800 degrees C. for 1 hour.
According to the description of Patent Document 3, In is included
in the Bi phase as is described above. In addition, In effectively
enhances adherence of Cu phase with Bi phase, because In lowers the
melting point of Cu. Also Sn lowers the melting point of Cu. A
phase diagram shown in FIG. 1 teaches that a Cu--In liquidus falls
steeply in a range of 0 to 20 mass % In. This teaching of phase is
believed to be utilized to effectively enhance adherence.
[0005] Patent Document 4 (Japanese Patent No. 3421724) proposes
that: hard particles co-present in the Pb or Bi phase of a sintered
copper-alloy prevent Pb and Bi from flowing; the hard particles are
placed on a cushion formed of the Pb and Bi phase and they attack
an opposite shaft in only reduced amounts; and, the once separated
hard particles are recaptured by the Pb or Bi phase. Abrasive wear
is therefore mitigated.
[0006] Patent Document 5 (Japanese Unexamined Patent Publication
No. 2001-220630) discloses that the following structure improves
seizure resistance and fatigue resistance of a Cu--Bi (Pb) based
sintered sliding material. The wear-resistant intermetallic
compound additives present in the peripheries of Bi or Pb phase
form convex portions on the surface of copper alloy, while the Bi
or Pb phase or Cu matrix form concave portions to form an oil
reservoir during sliding. An example of sintering conditions
includes 800-920 degrees C. for approximately 15 minutes.
[0007] Patent Document 6 (Japanese Patent No. 3108363) discloses
addition of indium (In) to copper alloy for use as a plain bearing.
In this method, corrosion resistance of a Cu--Sn--Pb alloy is
improved by In diffusion from an In-based overlay to the Cu--Pb--Sn
layer.
[0008] Patent Document 1: Japanese Examined Patent Publication No.
Hei 8-11945
[0009] Patent Document 2: Japanese Examined Patent Publication No.
Hei 7-9046
[0010] Patent Document 3: Japanese Unexamined Patent Publication
No. Hei 10-330868
[0011] Patent Document 4: Japanese Patent No. 3421724
[0012] Patent Document 5: Japanese Unexamined Patent Publication
2001-220630
[0013] Patent Document 6: Japanese Patent No. 3108363
[0014] Non Patent Document No. 1: FRICTION AND MATERIALS, Second
Edition (1995), ERNEST RABINOWICZ, John Wiley & Sons. Inc.
pages 32, 38.
DISCLOSURE OF INVENTION
Problems to be Solved by Invention
[0015] In a Cu alloy containing Pb or Bi, they are virtually
undissolved in the Cu matrix, or they form intermetallic compound.
Therefore, Pb and Bi form a minority phase distinguished from and
dispersed in the Cu matrix. Since Bi is softer than Cu, Bi exhibits
conformability. However, since Bi is harder than Pb, the
conformability and also the seizure resistance of Bi are inferior
to those of Pb. In addition, since the adhesion resistance of
Cu--Bi based or Cu--Sn--Bi based alloy is lower than that of
Cu--Sn--Pb based alloy, and also since conformability of the former
alloy is low, when Bi of the former alloy adheres onto an opposite
shaft, seizure of the former alloy is likely to occur as compared
with the case of the latter Cu--Sn--Pb based alloy.
[0016] In is alloyed in the Bi phase of the Cu--Sn--Bi--In based
copper alloy proposed in Patent Document 3. The In-alloyed Bi phase
has a considerably low melting point and therefore the sliding
properties deteriorate.
Means for Solving the Problems
[0017] The present invention aims to improve seizure resistance of
a Cu--Bi based sintered alloy sliding material and to obtain a
novel function of In. For this purpose, a Pb-free copper-based
sintered sliding material provided by the present invention
contains 0.5 to 15.0 mass % Bi and 0.3 to 15.0 mass % In, with the
balance being Cu and inevitable impurities, and is characterized by
the existence of Cu, Bi, and In in the material as follows, namely,
a Cu matrix containing In, a Bi phase, and an In concentrated
region in said Cu matrix at a boundary of said Bi phase.
[0018] The present invention is described in detail herein
below.
(1) Alloy Composition
[0019] In the Cu--Bi--In based sintered alloy according to the
present invention, when the Bi content is less than 0.5%, seizure
resistance is poor, and the amount of In concentrated layer is very
small. On the other hand, when the Bi content is more than 15.0%,
strength lowers and concentration of In occurs with difficulty. A
lining buckles and seizure occurs during operation under high load.
Bi content is therefore 0.5 to 15.0%. A preferable Bi content is
1.0 to 8.0%. The content referred to in the present section of
"Alloy Composition" is based on mass %. Hard particles and a solid
lubricant may be added in the copper based sintered sliding
material described hereinbelow. These additives are not considered
part of the composition of the copper alloy, as long as the alloy
composition is concerned.
[0020] When the In content is less than 0.3%, although In
concentrated regions may be formed, they are only slightly
effective. On the other hand, when the In content is more than 15%,
concentration of In occurs with difficulty, and seizure occurs. The
In content is therefore 0.3 to 15.0%. A preferable In content is
0.5 to 6.0%.
[0021] In addition, 0.5 to 6.0% of Sn can be added to enhance load
resistance. When the Sn content is less than 0.5%, Sn is only
slightly effective in enhancing the strength. On the other hand,
when the Sn content is more than 15.0%, intermetallic compounds are
liable to form, thereby embrittling the alloy. However, the total
content of In+Sn must be in a range of 1.0 to 15.0%. The balance of
the above mentioned components is inevitable impurities and Cu. The
impurities are usual ones. Among them, Pb at an impurity level is
included.
[0022] If necessary, the following additive elements are added to
the copper-based sliding material according to the present
invention. For example, 0.5% or less of P can be added to lower
melting temperature of Cu and hence improve sinterability. When the
P content exceeds 0.5%, the copper alloy embrittles. In the P-added
composition, a forming temperature of a Cu--P liquid phase is
higher than a forming temperature of a Bi liquid phase. This means
that when sintering is carried out under the presence of a Cu--P
liquid phase, Bi remains in a molten state. Formation temperature
of the Bi phase is believed to be lower than the liquid-phase
sintering temperature.
[0023] From 0.1 to 5.0% of Ni can be added to enhance strength and
corrosion resistance. When the Ni content is less than 0.1%, Ni is
only slightly effective for enhancing strength. On the other hand,
when the Ni content exceeds 5.0%, an intermetallic compound is
liable to form and the alloy embrittles. Ni is uniformly dissolved
in a solid Cu alloy.
[0024] Hard particles as proposed in Patent Document No. 2, and
such Fe-based compound hard-particles as Fe.sub.2P, Fe.sub.3P, FeB,
Fe.sub.2B, and Fe.sub.3B having improved sinterability with Cu
alloy, can be added in the present invention. The content of hard
particles described in the present paragraph is based on the entire
copper-based sintered sliding material. Meanwhile, the content of
Bi, In, or the like is based on the material excepting hard
particles. When the content of hard particles is less than 0.1%,
seizure resistance and wear resistance are poor. On the other hand,
when the content of hard particles exceeds 10.0%, the hard
particles impair the fatigue resistance and damage an opposite
material and lower sinterability. A preferable content of the hard
particles is 1.0 to 5.0%.
[0025] Solid lubricant, such as MoS.sub.2, graphite, and the like
can be added in an amount of 5.0% or less to copper alloy as a
composite component.
(2) Properties of Alloy
[0026] The conformability and low adhesion property of copper-based
sintered sliding material according to the present invention are
obtained from the Bi phase and In-concentrated regions in the
copper matrix, respectively.
[0027] (a) Physical properties of a material are said to be
employable as an alternative index of sliding properties. The
adhesion property of material can be related to such affinity to
opposite material, usually Fe, that said material and opposite
material have compatibility to form an alloy. Consideration is made
based on the data shown in pages 32 and 38 of Non-Patent Document
1, FRICTION AND WEAR OF MATERIALS, second Edition, ERNEST
RABINOWICSZ, John Wiley & Sons. Cu and Fe are a combination of
material relatively easy to form an alloy. However, since In and Fe
are incompatible, In is concentrated in the Cu matrix and
presumably acts negatively on the characteristics of Cu, lowering
adhesivity of Cu. Bi is also difficult to form an alloy of Fe
according to the equilibrium phase diagram of metal. Bi is
presumably incompatible and seems to have low adhesivity.
[0028] (b) Conformability can be evaluated by hardness of bulk
material. That is, the higher the hardness, the better is the
conformability. Although hardness of Bi is not as low as Pb, Bi
exhibits conformability. Bi and Pb do not form an intermetallic
compound with Cu. Bi is not dissolved in solid Cu. Bi therefore
forms a minority phase.
(3) Alloy Structure
[0029] Structure of the Cu--Bi--In based sintered alloy according
to the present invention is formed of Cu, Bi, and In as follows.
Sn, In, and the like are contained in the Cu matrix as solutes.
Intermetallic compounds such as Cu--Sn, Cu--In, and the like are
precipitated in the Cu matrix. The Cu matrix is therefore
distinguished from a Bi phase. Bi is present in the boundaries of
Cu crystal grains.
[0030] First of all, Cu and Bi are separated from each other in the
Cu--Bi binary system. Bi has no solubility in Cu, while In shows
solubility in Cu. The solubility of In decreases at lower
temperature but remains appreciable even at room temperature
(25.degree. C.). At a sintering temperature of Cu--Bi--In based
alloy powder, the solute In in the Cu matrix diffuses to the Bi
liquid phase, which is then converted to a Bi--In liquid phase. The
liquid phase and the Cu solid phase are present in mixture.
Sintering is carried out under the condition of mixed phases, i.e.,
a Cu solid phase, and a liquid phase, i.e., a Bi+In liquid phase.
When P is added, sintering proceeds under the condition of mixed
solid and liquid phases. That is, the solid phase is Cu--P solid
phase, and the liquid phase is Bi+In liquid phase.
[0031] In Patent Document 3, the post sintering structure is a
mixed Bi and In structure. The structure according to the present
invention is as follows. The In phase and Bi phase are separated
from each other, In concentration is high around the Bi phase, and
an element other than Bi is not detected in the Bi phase.
Solubility of In in Cu at low temperature is utilized for the
following re-diffusion. That is, In in the liquid phase again
diffuses from the Bi phase to the Cu matrix during cooling after
sintering. Thus, In concentrated regions are formed. On the other
hand, when diffusion is carried out for a long period of time, In
is uniformly dispersed in the Cu matrix and hence no concentrated
region is formed.
[0032] The above structures can be distinguished from each other,
with an EPMA, which detects X-ray intensities of the respective
elements. The detected X-ray intensities are converted to color
mapping. When one pays attention to color indications, the granular
Cu matrix structure and the Bi-phase boundary structure are
distinguished from each other. Likewise, the In concentration is
detected with an EPMA, and, regions corresponding to different In
concentrations are obtained. There is a region in the Cu matrix at
a boundary of Cu matrix/Bi phase, which region is distinguishable
from another region by color. In the present invention, an EPMA
(product of Nihon Denshi Co. Ltd., type-JXA-8100) was used, and
X-ray detection and color mapping were carried out at an
accelerating voltage of 20 kV and a current value of
3.times.10.sup.-8 A.
[0033] The sintering process as described above is achieved under
the following preferable sintering conditions: holding at 750
degrees C. to 950 degrees C. for 20s or longer; and cooling down to
the melting point (270 degrees C.) at a cooling speed of
essentially 5 degrees C./sec or more. Namely, when the holding time
at sintering is excessively short, diffusion time of solute In from
Cu matrix to the Bi liquid phase is not satisfactory long so that
In concentrated regions are formed with difficulty. When the
cooling speed is too high, the diffusion time of In from the Bi+In
liquid phase to the Cu matrix is so short that the In concentrated
regions are formed with difficulty, as well. On the other hand,
when the cooling speed is too slow, re-diffusion is promoted to
such a level that In is uniformly dispersed in the Cu matrix and
hence the concentrated regions are failed to be formed, as
well.
[0034] Sn and Ni are optional elements described hereinabove and
are mainly dissolved in the Cu matrix. P forms a Cu--P based
minority phase when added in a large amount. The present invention
is hereinafter described in detail by way of examples.
BEST MODES FOR CARRYING OUT INVENTION
Example 1
[0035] Cu--Bi--In--Sn based, Cu--Bi--In based, or Cu--Bi based pre
alloy powder (particle diameter-150 .mu.m, atomized powder) is
sprayed onto a steel sheet to provide an approximately 1 mm thick
layer having a composition showing in Table 1. Primary sintering
was carried out at 750-950 degrees C. for 200 seconds of sintering
time in a hydrogen-reducing atmosphere. Cooling speed was 20
degrees c/s. Subsequently, rolling was carried out, and then a
secondary sintering was carried out under the identical conditions.
The resultant sintered compacts were used as test samples. However,
in Comparative Examples 1-7 the holding time at sintering was 15
seconds and the other conditions were the same as in the
Examples.
Testing Method of Seizure Resistance
[0036] A bush journal type tester was used for a seizure test. Test
samples were worked in a bush form 22 mm in diameter and 10 mm in
length. A test was carried out under the following conditions.
[0037] Opposite Material: SCM415H(HV 720-850, Rz 0.8-1.0) [0038]
Loading step: 3 MPa/5 minute [0039] Revolution number: 3000 rpm
[0040] Oil grade: additive-free paraffin oil
[0041] Oil temperature: 80 degrees C.
[0042] When the temperature of the back surface of a bush elevated
to 160 degrees C. or higher, judgment of seizure was rendered.
TABLE-US-00001 TABLE 1 Seizure Bearing Material Test-Seizure In-
Surface Mass Composition concentrated Pressure- Cu Bi In Sn Layer
(MPa) A 1 Bal. 0.4 4.0 4.0 Absent 21 2 Bal. 30.0 4.0 4.0 .uparw. 18
3 Bal. 5.0 0.3 8.0 .uparw. 27 4 Bal. 5.0 20.0 -- .uparw. 30 5 Bal.
5.0 4.0 15.0 .uparw. 18 6 Bal. 5.0 -- 4.0 .uparw. 18 7 Bal. 15.0 --
-- .uparw. 21 B 1 Bal. 1.0 0.4 1.5 present >36* 2 Bal. 1.0 0.4
14.0 .uparw. >36* 3 Bal. 1.0 15.0 -- .uparw. >36* 4 Bal. 5.0
0.4 1.5 .uparw. >36* 5 Bal. 5.0 0.4 14.0 .uparw. >36* 6 Bal.
5.0 15.0 -- .uparw. >36* 7 Bal. 10.0 0.4 1.5 .uparw. >36* 8
Bal. 10.0 0.4 14.0 .uparw. >36* 9 Bal. 10.0 15.0 -- .uparw.
>36* 10 Bal. 15.0 0.4 1.5 .uparw. >36* 11 Bal. 15.0 0.4 14.0
.uparw. >36* 12 Bal. 15.0 15.0 -- .uparw. >36* 13 Bal. 5 5 5
.uparw. >36* 14 Bal. 5 5 5 .uparw. >36* 15 Bal. 5 5 5 .uparw.
>36* 16 Bal. 5 5 5 .uparw. >36* Remarks A- Comparative
Examples B- Inventive Examples *No seizure at surface pressure of
36 MPa
[0043] In Table 1, the seizure resistance of any of Comparative
Examples 1-7 is poor because of the following reasons. (a) No.
1-low Bi content, (b) No. 2-high Bi content, (c) No. 3-low In
content, (d) No. 4-high In content, (e) No. 5-high Sn+In content,
(f) No. 6,7-no In addition. In contrast, the inventive examples
reveal improved seizure resistance. FIG. 2 shows an EPMA chart of
test sample No. 14. FIG. 3 illustrates information obtained from
color mapping of In concentration shown in FIG. 2. The following
facts are clear from FIG. 3. [0044] The "In concentration min
region" is blue colored and has a lowest In concentration. This
region coincides with the region where the Bi concentration is
highest (red or pink). [0045] The "In concentration low region" is
green colored and the Bi concentration is black (not detected).
[0046] The "In concentration max-middle region" shown in FIG. 3 is
a region where green, yellow, and red concentrations are mixed, and
represents an In concentrated region. This region is present at the
boundary of a Bi phase. Therefore, In is present in the Cu matrix
and concentrated at the boundary of a Bi phase.
Example 2
[0047] Ni, Cu was added to the copper alloy powder used in Example
1 and sintered. Hard matter and solid lubricant were added to
hundred percentage of the copper alloy powder used in Example 1 ,
and were sintered. The respective compositions are shown in Table
2. Example product Nos. 18, 20, 22, and 24 exhibited improved
property over the Comparative Examples of Table 1. The Ni
concentration was uniform in the matrix. P was also dispersed
uniformly in the matrix.
TABLE-US-00002 TABLE 2 Seizure Bearing Material Test-Seizure In
Surface Mass Composition (hundred %) concentrated Pressure- No. Cu
Bi In Sn P Ni Fe.sub.3P graphite region (MPa) 17 Bal. 5 5 5 0.5 --
-- -- present >36 18 Bal. 5 5 5 0.1 -- -- -- .uparw. >36 19
Bal. 5 5 5 -- 5.sup. -- -- .uparw. >36 20 Bal. 5 5 5 -- 0.1 --
-- .uparw. >36 21 Bal. 5 5 5 -- -- 10 -- .uparw. >36 22 Bal.
5 5 5 -- -- 0.1 -- .uparw. >36 23 Bal. 5 5 5 -- -- -- 5.sup.
.uparw. >36 24 Bal. 5 5 5 -- -- -- 0.1 .uparw. >36
INDUSTRIAL APPLICABILITY
[0048] The sintered copper alloy according to the present invention
can be used for various sliding members, such as an AT (automatic
transmission) bush, bearings of a connecting rod, and a sliding
material of a compressor. High-level seizure resistance attained by
the present invention is effectively exhibited in these
applications.
BRIEF DESCRIPTION OF DRAWINGS
[0049] [FIG. 1] a Cu--In binary phase diagram
[0050] [FIG. 2] an EPMA chart showing an In concentrated region
[0051] [FIG. 3] an illustrative drawing of FIG. 2
* * * * *