U.S. patent application number 13/390883 was filed with the patent office on 2012-06-14 for cu-based sintered sliding member.
This patent application is currently assigned to Diamet Corporation. Invention is credited to Yoshinari Ishii, Tsuneo Maruyama, Yoshiki Tamura.
Application Number | 20120145284 13/390883 |
Document ID | / |
Family ID | 43628509 |
Filed Date | 2012-06-14 |
United States Patent
Application |
20120145284 |
Kind Code |
A1 |
Ishii; Yoshinari ; et
al. |
June 14, 2012 |
Cu-BASED SINTERED SLIDING MEMBER
Abstract
A Cu-based sintered sliding member that can be used under
high-load conditions. The sliding member is age-hardened, including
5 to 30 mass % Ni, 5 to 20 mass % Sn, 0.1 to 1.2 mass % P, and the
rest including Cu and unavoidable impurities. In the sliding
member, an alloy phase containing higher concentrations of Ni, P
and Sn than their average concentrations in the whole part of the
sliding member, is allowed to be present in a grain boundary of a
metallic texture, thereby achieving excellent wear resistance.
Hence, without needing expensive hard particles, there can be
obtained, at low cost, a Cu-based sintered sliding member usable
under high-load conditions. Even more excellent wear resistance is
achieved by containing 0.3 to 10 mass % of at least one solid
lubricant selected from among graphite, graphite fluoride,
molybdenum disulfide, tungsten disulfide, boron nitride, calcium
fluoride, talc and magnesium silicate mineral powders.
Inventors: |
Ishii; Yoshinari;
(Niigata-shi, JP) ; Maruyama; Tsuneo;
(Niigata-shi, JP) ; Tamura; Yoshiki; (Niigata-shi,
JP) |
Assignee: |
Diamet Corporation
Niigata-shi
JP
|
Family ID: |
43628509 |
Appl. No.: |
13/390883 |
Filed: |
August 27, 2010 |
PCT Filed: |
August 27, 2010 |
PCT NO: |
PCT/JP2010/064565 |
371 Date: |
February 16, 2012 |
Current U.S.
Class: |
148/412 ;
148/419 |
Current CPC
Class: |
F16C 33/121 20130101;
B22F 5/00 20130101; B22F 3/12 20130101; B22F 2302/40 20130101; B22F
3/26 20130101; C22C 9/06 20130101; B22F 2301/10 20130101; C22C
1/0425 20130101; C22C 32/0089 20130101; B22F 2302/45 20130101; C22C
9/02 20130101; C22C 32/0084 20130101; B22F 1/007 20130101; B22F
2003/248 20130101 |
Class at
Publication: |
148/412 ;
148/419 |
International
Class: |
C22C 9/06 20060101
C22C009/06 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 31, 2009 |
JP |
2009-201072 |
Claims
1. A Cu-based sintered sliding member that is age-hardened, said
sliding member comprising: 5 to 30% by mass of Ni; 5 to 20% by mass
of Sn; 0.1 to 1.2% by mass of P; and the rest including Cu and
unavoidable impurities, wherein said Cu-based sintered sliding
member comprises an alloy phase present in a grain boundary of a
metallic texture, said alloy phase including higher concentrations
of Ni, P and Sn than average concentrations of Ni, P and Sn in the
whole sliding member.
2. The Cu-based sintered sliding member according to claim 1,
further comprising 0.3 to 10% by mass of at least one solid
lubricant selected from among graphite, graphite fluoride,
molybdenum disulfide, tungsten disulfide, boron nitride, calcium
fluoride, talc and magnesium silicate mineral powders.
3. The Cu-based sintered sliding member according to claim 1,
further comprising 0.3 to 10% by mass of at least one solid
lubricant selected from graphite and graphite fluoride.
4. The Cu-based sintered sliding member according to claim 1,
further comprising 0.3 to 10% by mass of at least one solid
lubricant selected from among molybdenum disulfide, tungsten
disulfide, boron nitride, calcium fluoride, talc and magnesium
silicate mineral powders.
5. The Cu-based sintered sliding member according to claim 2,
wherein at least one solid lubricant is selected from graphite and
graphite fluoride, and at least one solid lubricant is selected
from among molybdenum disulfide, tungsten disulfide, boron nitride,
calcium fluoride, talc and magnesium silicate mineral powders.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This application is a U.S. National Phase application under
35 U.S.C. .sctn.371 of International Patent Application No.
PCT/JP2010/064565, filed Aug. 27, 2010, and claims the benefit of
Japanese Patent Application No. 2009-201072, filed Aug. 31, 2009,
all of which are incorporated by reference herein. The
International Application was published in Japanese on Mar. 3, 2011
as International Publication No. WO 2011/024941 under PCT Article
21(2).
FIELD OF THE INVENTION
[0002] The present invention relates to a Cu-based sintered sliding
member, particularly to a Cu-based sintered sliding member
compatible with use under high load conditions.
BACKGROUND OF THE INVENTION
[0003] As for bearings used for an automobile, an expensive ball
bearing is used for high load applications, such as a bearing for
an ABS system of an automobile, while an inexpensive Fe--Cu-based
sintered bearing is used for a motor system of an automobile wiper
or the like. Due to reduction in size of the motor system, however,
the bearing for the motor system is also progressively reduced in
size to thereby increase a load applied to the bearing parts.
Therefore, ever more excellent performances in wear resistance and
seizure resistance are required for the bearing parts.
[0004] Recently, to meet strong demands for cost reduction from the
market, employing an inexpensive sintered bearing instead of an
expensive ball bearing is under consideration even for high load
applications such as the foregoing ABS system of the automobile.
When using the conventional Cu-based sintered sliding member,
however, a load applied thereto is too heavy for it and hence the
load exceeds its allowable load range, thus making it impossible to
use the member. Further, Fe--Cu based sintered sliding members
whose hardness and strength are higher than those of the Cu-based
sintered sliding members contain Fe, while a shaft borne by the
Cu-based sintered sliding member is also made of an Fe-based metal,
and thus, abnormal friction and seizure are likely to occur due to
the same-metal phenomenon, even though the probability of the
occurrence thereof is low, thus leading to the problem that the
reliability thereof as a sliding member is insufficient. Thus, a
Cu-based sintered sliding member which is less expensive than the
expensive ball bearings and is capable of being used under higher
load conditions than in the past has been sought after.
[0005] As a conventional art with respect to the Cu-based sintered
sliding member usable under high load conditions, there is
disclosed a Cu-based sintered sliding member (in e.g., Japanese
unexamined patent application publication No. H5-195117) having
excellent wear resistance and seizure resistance under
high-temperature, high-load and poor-lubrication conditions when it
is used for a valve guide or the like of an internal-combustion
engine.
[0006] The Cu-based sintered alloy according to the conventional
art is a Cu--Ni--Sn based alloy whose composition gives rise to a
spinodal decomposition through an aging treatment. By undergoing
the spinodal decomposition, the Cu--Ni--Sn based alloy is allowed
to be formed with a microstructure to thereby strengthen its
metallic substrate. Further, through the addition of Ni-based hard
particles having excellent adhesiveness to the metallic substrate
along with MoS.sub.2 as a solid lubricant, wear resistance and
seizure resistance are imparted thereto under high-temperature,
high-load and poor-lubrication conditions.
[0007] The Ni-based hard particles used in the conventional art,
however, are not only expensive but a vacuum sintering process is
required therefor as Cr is contained in the Ni-based hard
particles, thus leading to high manufacturing cost, resulting in an
insufficient cost advantage.
SUMMARY OF THE INVENTION
Problem to be Solved by the Invention
[0008] Therefore, it is an object of the present invention to
provide a Cu-base sintered sliding member which eliminates the need
for the addition of expensive hard particles and is capable of
being used under high load conditions.
Means for Solving the Problem
[0009] A first aspect of the present invention is a Cu-based
sintered sliding member, age-hardened and including:
[0010] 5 to 30% by mass of Ni;
[0011] 5 to 20% by mass of Sn;
[0012] 0.1 to 1.2% by mass of P; and
[0013] the rest including Cu and unavoidable impurities,
[0014] wherein said Cu-based sintered sliding member includes an
alloy phase present in a grain boundary of a metallic texture, the
alloy phase including higher concentrations of Ni, P and Sn than
average concentrations of Ni, P and Sn in the whole sliding
member.
[0015] A second aspect the present invention is the Cu-based
sintered sliding member according to the first aspect, further
including 0.3 to 10% by mass of at least one, serving as a solid
lubricant, selected from among graphite, graphite fluoride,
molybdenum disulfide, tungsten disulfide, boron nitride, calcium
fluoride, talc and magnesium silicate mineral powders.
Effects of the Invention
[0016] According to the constitution described above, by adding P
to the Cu--Ni--Sn based alloy while utilizing a property of the
Cu--Ni--Sn based alloy giving rise to hardening by aging treatment,
strength of the alloy metallic substrate is further increased, and
at the same time, the Ni--P--Cu--Sn alloy phase whose concentration
of each of Ni, P and Sn is higher than that of the metallic
substrate is allowed to be present in the grain boundary. As a
result, there can be obtained the Cu-based sintered sliding member
having excellent wear resistance, realizing low-cost production due
to no need of the expensive hard particles, and capable of being
used under the high-load condition of a bearing used.
[0017] Further, addition of the solid lubricant permits the wear
resistance to be improved. The solid lubricant may contain one or
more substances selected from among graphite, graphite fluoride,
molybdenum disulfide, tungsten disulfide, boron nitride, calcium
fluoride, talc (Mg.sub.3SiO.sub.4(OH).sub.2) and magnesium silicate
(MgSiO.sub.3) mineral powders.
BRIEF DESCRIPTION OF THE DRAWING
[0018] These and other features and advantages of the present
invention will become more readily appreciated when considered in
connection with the following detailed description and appended
drawing, wherein like designations denote like elements in the
various views, and wherein:
[0019] FIG. 1 is an electron microscope photograph illustrating an
embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Mode for Carrying Out the Invention
[0020] Preferred embodiments of the present invention are described
in detail with reference to the accompanying drawings. The
hereinbelow-described embodiments shall not be construed as
limiting the subject matter of the present invention set forth in
claims. Further, not all features described hereunder are essential
requirements of the present invention. In each embodiment, a novel
Cu-based sintered sliding member different from the conventional
ones is employed so that there can be obtained an unprecedented
Cu-based sintered sliding member, the description of which will be
given hereinbelow, respectively.
[0021] According to the present invention, while taking advantage
of such a property of the Cu--Ni--Sn based alloy that it gives rise
to hardening by an aging treatment, the alloy metallic substrate is
further increased in strength by adding P thereto, and the
Ni--P--Cu--Sn alloy phase having higher concentrations of Ni, P and
Sn than the metallic substrate is allowed to be present in the
grain boundary, thus enabling the excellent wear resistance to be
obtained, eliminating the need for the expensive hard particles and
thus leading to low cost, whereby there can be obtained the
Cu-based sintered sliding member that is capable of being used
under the high load usage environment of bearings. Furthermore,
adding the solid lubricant agent enable the wear resistance to be
improved. As to the property of the Cu--Ni--Sn based alloy giving
rise to hardening by an aging treatment, it is known that within a
given composition range, Ni and Sn are dissolved in Cu to form a
single alpha-phase structure, thus giving rise to a spinodal
hardening by an aging treatment. Here, the wording, spinodal
hardening, means such phenomenon that due to a structure produced
by spinodal decomposition having a periodic structure on the order
of several nanometers to thereby form an extremely fine structure,
deformation resistance increases by an increase in strain energy or
the like, thereby increasing hardness or strength.
[0022] Next, a description is given of the reason why the
composition of a sintered Cu alloy that constitutes the Cu-based
sintered sliding member of the present invention is to be
limited.
(a) Ni: 5 to 30% by Mass
[0023] Ni, together with P, Sn and Cu, forms a solid solution of a
metallic substrate to improve the strength of a sintered alloy by
age hardening. Further, an alloy phase whose Ni, P and Sn
concentrations are higher than those of the metallic substrate is
allowed to be present in the grain boundary, thereby contributing
to improving wear resistance. An amount of Ni required for the
hardening by aging treatment is at least 5% by mass, while if more
than 30% by mass of Ni is added, there is recognized no improvement
of hardness attributable to the aging treatment, thus undesirably
leading to the opposite effect of an increased raw material
cost.
(b) Sn: 5 to 20% by Mass
[0024] Sn, together with Ni, P and Cu, forms the solid solution of
the metallic substrate to improve the strength of a sintered alloy
by age hardening. Further, the alloy phase whose Ni, P and Sn
concentrations are higher than those of the metallic substrate is
allowed to be present in the grain boundary, thereby contributing
to improving wear resistance. An amount of Sn required for the
hardening by aging treatment is at least 5% by mass and if more
than 20% by mass of Sn is added, there is recognized no improvement
of hardness attributable to the aging treatment, thus undesirably
leading to the opposite effect of an increased wearing
aggressiveness to other materials.
(c) P: 0.1 to 1.2% by Mass
[0025] P improves sintering performance and forms, together with
Ni, Sn and Cu, the solid solution of the metallic substrate to
improve the strength of a sintered alloy. Further, the alloy phase
whose Ni, P and Sn concentrations are higher than those of the
metallic substrate is allowed to be present in the grain boundary,
thereby contributing to improving wear resistance. When the content
of P is less than 0.1% by mass, a predetermined wear resistance
cannot be obtained. Contrarily, when the content of P exceeds 1.2%
by mass, wearing aggressiveness to a sliding counterpart member is
increased, thus undesirably wearing the same.
(d) Solid Lubricant: 0.3 to 10% by Mass
[0026] The solid lubricant may contain 0.3 to 10% by mass of at
least one of graphite, graphite fluoride, molybdenum disulfide,
tungsten disulfide, boron nitride, calcium fluoride, talc
(Mg.sub.3SiO.sub.4(OH).sub.2) and magnesium silicate (MgSiO.sub.3)
mineral powders. When the content of the solid lubricant is less
than 0.3% by mass, the improvement in wear resistance cannot be
obtained. Contrarily, when the content of the solid lubricant
exceeds 10% by mass, its strength noticeably decreases, and thus it
is not desirable.
[0027] Here, graphite and graphite fluoride are present as free
graphite and free graphite fluoride dispersed in the metallic
substrate, and impart an excellent lubricating property to a
sintered alloy to thereby contribute to the improvement in wear
resistance of the sintered alloy. Further, molybdenum disulfide,
tungsten disulfide, boron nitride, calcium fluoride, talc
(Mg.sub.3SiO.sub.4(OH).sub.2) and magnesium silicate (MgSiO.sub.3)
mineral powders serve to impart an excellent lubricating property
to the sintered alloy and to lessen the chance of metal contact
between sliding members, thus contributing to the improvement in
wear resistance of the sintered alloy. In addition, talc becomes
enstatite after sintering.
Embodiment 1
[0028] Next is a description of embodiments with reference to an
appended drawing.
[0029] In manufacturing the sintered alloy, raw powders are filled
in a mold of a required shape and are subjected to powder
compacting, thus obtaining a compact with a required density. This
compact is sintered in a reductive atmosphere to obtain a sintered
alloy. Then, this sintered alloy is subjected to a sizing process
to satisfy the required dimensional accuracy using a mold. The
size, density, hardness and strength of the sintered alloy after
the sizing process are tested to select, as products, ones which
have passed the test. Examples of such products include a bearing
acting as a sliding member.
Experimental Examples
[0030] As raw powders, there were prepared electrolytic Cu powders
with 100 mesh diameter, Sn atomized powders with 250 mesh diameter,
Cu-based atomized powders including 8% by mass of P with 200 mesh
diameter, Cu-based atomized powders including 30% by mass of Ni
with 250 mesh diameter, while as additive solid lubricants, there
were prepared graphite powders with 20 .mu.m average diameter,
molybdenum disulfide powders with less than 150 .mu.m average
diameter, calcium fluoride powders with 60 .mu.m average diameter,
and talc powders with 20 .mu.m average diameter.
[0031] These raw powders were mixed so as to have the final
compositions shown in Table 1 and Table 2, to which were added 0.5%
by mass of zinc stearate and then mixed together for 20 minutes
using a V-type mixer. Thereafter, pressure molding was applied to
the mixed compound at a given pressure within 200 to 300 MPa to
produce green compacts, Then, these green compacts were sintered at
a given temperature within a range of 840 to 940 degrees C. in an
atmosphere of an endothermic gas obtained by mixing a natural gas
and an air and allowing the same to pass through a heated catalyst
to thereby be decomposed and denatured, and then they were
subjected to a sizing process, and to an aging treatment for 1 hour
in a non-oxidizing atmosphere at a given temperature within 350 to
450 degrees C., followed by impregnating a Cu-based sintered
sliding member thus produced with a synthetic oil, whereby
ring-shaped test pieces of Cu-based sintered sliding members were
produced, said test pieces each having a size of 18 mm outer
diameter, 8 mm inner diameter and 8 mm height, and including: a
Cu-based sintered sliding member with the ingredient composition
shown in Table 1 (hereunder, referred to as an example of the
present invention), and for comparison purpose, a Cu-based sintered
sliding member with P removed therefrom and a Cu-based sintered
sliding member with an ingredient composition departing from that
of the example of the present invention (hereunder, referred to as
comparative examples). Note that the Cu-based sintered sliding
members thus obtained had air holes distributed in their metallic
substrates in a proportion of 5 to 25% by mass.
[0032] The following tests were performed using the ring-shaped
test pieces including Cu-based sintered sliding members 1 to 13 of
the present invention (hereunder, referred to as examples 1 to 13
of the present invention), Cu-based sintered sliding members 1 to
13 for comparison purpose (hereunder, referred to as comparative
examples 1 to 13), and conventional examples 1, 2 including a
Cu-based sintered sliding member subjected to no age hardening and
a Fe--Cu-based sintered sliding member. The results of radial
crushing tests and wear resistance tests are shown in Tables 1 and
2.
[0033] Here, Table 1 shows the examples 1 to 4 of the present
invention, the comparative examples 1 to 8, and the conventional
examples 1 to 2, while Table 2 shows the examples 5 to 13 of the
present invention, and the comparative examples 9 to 13.
[0034] Radial Crushing Test:
[0035] Load was applied radially to each of the ring-shaped test
pieces including the examples 1 to 13 of the present invention, the
comparative examples 1 to 13, and the conventional examples 1 to 2.
Then, the loads applied to the rings at the moment the ring-shaped
test pieces were broken were measured to calculate the strengths
thereof. The strengths calculated are shown in a column labeled as
"radial crushing strength" in Tables 1, 2.
[0036] Wear Resistance Test:
[0037] A shaft made of S45C steel was inserted into each of the
ring-shaped test pieces including the examples 1 to 13 of the
present invention, the comparative examples 1 to 13, and the
conventional examples 1 to 2. Then, the test was performed in such
a manner that the shaft was rotated at a speed of 75 m/min for
1,000 hours with a load being applied from the outside of the
ring-shaped test piece so that the pressure to the surface of the
test piece became 1.5 MPa in the radial direction (in the direction
perpendicular to the axial direction of the shaft). The maximum
abrasion depths after the tests on the respective sliding surfaces
of the ring-shaped test pieces and the shafts made of SC45 were
measured to evaluate wear resistance. The test results are depicted
in Tables 1, 2.
[0038] Note that the conditions under which the present wear
resistance tests were performed were determined on the assumption
of high-load conditions.
TABLE-US-00001 TABLE 1 Physical Properties after Aging Treatment
Maximum Radial Maximum Abrasion With or Ingredient Composition
(mass %) Crushing Hardness Abrasion Depth of Shaft Without Age Ni
Sn P Cu Strength(N/mm.sup.2) (Hv5) Depth (mm) Material (mm)
Hardening Examples of 1 9 8 0.3 the Rest 618 145 0.007 0.002 With
the Present 2 7 7 0.3 the Rest 538 136 0.012 <0.001 With
Invention 3 12 13 0.3 the Rest 654 158 0.006 0.002 With 4 25 17 0.4
the Rest 710 172 0.005 0.003 With Comparative 1 8 7 0* the Rest 491
127 0.027 0.002 With Examples 2 7 7 0* the Rest 426 115 0.032
<0.001 With 3 12 13 0* the Rest 511 132 0.022 0.001 With 4 12 10
1.4* the Rest 566 174 0.005 0.023 With 5 4* 2 0.2 the Rest 333 51
0.097 0.001 With 6 32* 19 1.0 the Rest 583 146 0.020 0.007 With 7 5
1* 0.2 the Rest 347 49 0.104 0.001 With 8 25 22* 0.5 the Rest 605
149 0.008 0.021 With Conven- 1 Cu--9%Sn--0.8%C--0.3%P 300 60
0.136.sup.++ 0.001.sup.++ Without tional 2 Fe--20%Cu--2%C 400 95
0.020 0.045 Without Examples (In the table, a * mark indicates the
figure is outside the scope of the present invention and a .sup.++
mark indicates measured data after 100 test hours.)
TABLE-US-00002 TABLE 2 Physical Properties after Aging Treatment
Maximum Radial Maximum Abrasion Ingredient Composition (mass %)
Crushing Hardness Abrasion Depth of Shaft Ni Sn P C MoS.sub.2
CaF.sub.2 MgSiO.sub.3 Cu Strength(N/mm.sup.2) (Hv5) Depth (mm)
Material (mm) Examples of 5 10 7 0.3 2 0 0 0 the Rest 536 106 0.002
<0.001 the Present 6 7 8 0.3 0 2 0 0 the Rest 553 110 0.003
<0.001 Invention 7 9 7 0.4 0 0 2 0 the Rest 566 121 0.004 0.001
8 8 8 0.3 0 0 0 2 the Rest 540 109 0.004 0.001 9 6 6 0.3 1 0 0 0
the Rest 502 102 0.007 <0.001 10 15 13 0.7 5 0 0 0 the Rest 711
154 0.002 <0.001 11 17 15 0.9 7 0 0 0 the Rest 697 174 0.002
<0.001 12 20 13.5 0.5 2 0 0 0 the Rest 669 158 0.004 <0.001
13 28 18 1.1 1 1 1 1 the Rest 645 167 0.006 0.001 Comparative 9 10
10 0* 2 0 0 0 the Rest 405 91 0.018 <0.001 Examples 10 9 7 0.8
11* 0 0 0 the Rest 255 48 0.038 <0.001 11 10 9 0.3 0 12* 0 0 the
Rest 223 44 0.064 <0.001 12 10 9 0.3 0 0 11* 0 the Rest 188 32
0.108 0.010 13 12 10 1.4* 0 0 0 11* the Rest 159 35 0.135 0.012 (In
the table, a * mark indicates the figure is outside the scope of
the present invention.)
[0039] The results shown in Tables 1, 2 indicate that the maximum
abrasion depths in the ring-shaped test pieces according to the
examples of the present invention were smaller than those in the
ring-shaped test pieces including the comparative examples and the
conventional examples. Hence, it is learnt that the ring-shaped
test pieces according to the present invention have excellent wear
resistance. On the other hand, it is learnt from the comparative
examples 1 to 13 whose ingredient compositions depart from the
scope of the present invention that the ring-shaped test pieces
according to the comparative examples 1 to 13 are inferior in
respect of at least one characteristic from among strength, wear
resistance and wearing aggressiveness to shaft. Table 1 shows that
the comparative examples 1 to 3 including less than 0.1% by mass of
P had larger maximum abrasion depths than the examples of the
present invention, while the comparative example 4 including more
than 1.2% by mass of P had larger maximum abrasion depths of the
counterpart shaft material as compared to the examples of the
present invention; the comparative example 5 including less than 5%
by mass of Ni had larger maximum abrasion depths as compared to the
examples of the present invention, while the comparative example 6
including more than 30% by mass of Ni had larger maximum abrasion
depths as well as larger maximum abrasion depths of the counterpart
shaft material as compared to the examples of the present
invention; and the comparative example 7 including less than 5% by
mass of Sn had larger maximum abrasion depths as compared to the
examples of the present invention, while the comparative example 8
including more than 20% by mass of Sn had larger maximum abrasion
depths of the counterpart shaft material as compared to the
examples of the present invention. Further, it is shown that the
comparative examples 1, 2, 3, 5 and 7 had inferior radial crushing
strength as compared to the examples of the present invention.
[0040] Table 2 shows that the comparative example 9 including less
than 0.1% by mass of P, the comparative examples 10 to 12 including
more than 10% by mass of the solid lubricant, and the comparative
example 13 including more than 10% by mass of the solid lubricant
as well as more than 1.2% by mass of P, had inferior radial
crushing strength as well as larger maximum abrasion depths, as
compared to the examples of the present invention.
[0041] The alloy of the example 1 of the present invention was
analyzed to determine Ni, P, Sn and Cu within the alloy phase in
which the concentration of each of Ni, P and Sn present in the
grain boundary of the metallic texture was higher than the average
concentration thereof in the whole alloy, using an electron-beam
microanalyzer (EPMA). The result obtained is shown in Table 3. An
electron microscope photograph (COMPO image) is shown in FIG. 1 as
one example of the alloy phase thus analyzed.
TABLE-US-00003 TABLE 3 Analytical Value (wt %) Ni P Sn Cu Example 1
of the Present Invention 64.342 10.820 14.057 9.995 Alloy Phase in
Grain Boundary
[0042] With an EPMA analytical condition set at the acceleration
voltage of 15 KV and the beam diameter .phi. of 1 .mu.m, the alloy
phase in the grain boundary shown in FIG. 1 was measured at five
places. The average value for each metal is shown in Table 3. It is
noted from the analysis result that the alloy of the example 1 of
the present invention included the specific alloy phase present in
the grain boundary, said specific alloy phase including higher Ni,
P and Sn concentrations than the average concentrations thereof in
the whole sintered alloy.
[0043] In addition, the present invention is not limited to the
foregoing embodiments and various modifications are possible. For
example, whilst the bearing, acting as a sliding member, having a
sliding surface in its inner circumferential surface, is described
as an example of the present invention in the foregoing
embodiments, the Cu-based sintered sliding member according to
present invention may be applicable to other sliding members having
sliding surfaces.
* * * * *