JPS6342337A - Sliding member - Google Patents

Abstract

PURPOSE:To obtain a sliding member having excellent wear resistance, seizure resistance, etc., by combining a member having a sliding face reinforced with specifically composed of Al2O3-SiO2 fibers and a member having a sliding face thermally sprayed and coated with a hard particle dispersion strengthened composite material. CONSTITUTION:The sliding member is constituted of the two members which slide in contact with each other. At least the sliding face part of a 1st member is constituted of the fiber reinforced composite metallic material consisting of the Al2O3-SiO2 fibers having the compsn. composed of >=40wt% Al2O3 and the balance SiO2 and having 3-30% volume ratio as reinforcing fibers and an Al alloy or Mg alloy as matrix. On the other hand, at least the sliding face part of the 2nd member is constituted of the metal coated with the thermal spraying layer of the particle dispersion strengthened composite metallic material consisting of metal oxide particles such as Cr2O3, TiO2, ZrO2, and Al2O3 having >=800Hv hardness and 25-85% volume ratio as a reinforcing material and metal such as Fe or Ni or alloy essentially consisting thereof as matrix.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a sliding member consisting of a first member and a second member that are in contact with each other and slide relative to each other. The second member is made of a composite material made of aluminum alloy or magnesium alloy reinforced with alumina-silica fibers, and the second member is a metal coated with a sprayed layer of a metal composite material dispersed in metal oxide particles. This relates to a sliding member constructed of.

BACKGROUND OF THE INVENTION In a sliding member made of two members that come into contact with each other and slide relative to each other, depending on the combination of the two members, the amount of wear of one or both of those members becomes large.
May cause premature end of life. In order to deal with this problem, for example, Japanese Patent Application Laid-open No. 58-93838 and Japanese Patent Application Laid-open No. 58-93839 filed by the same applicant as the present applicant disclose that aluminum alloys or magnesium alloys are used as a matrix. One member is made of a fiber-reinforced metal composite material reinforced with inorganic fibers such as alumina-silica fibers, and the other member is made of steel of a predetermined hardness. Attempts are being made to improve the dynamic characteristics.

Problems to be Solved by the Invention However, in a sliding member consisting of two members that come into contact with each other and slide relative to each other, if one of the members is made of a fiber-reinforced metal composite material, the other Depending on the material of one member, wear of the other member may increase, and problems such as seizure may occur between these members.

The inventors of the present application have proposed a sliding member consisting of a first member and a second member that are in contact with each other and slide relative to each other, in which the first member is a composite material in which the reinforcing fiber is alumina-silica fiber. When the second member is made of metal and the second member is made of metal, various experimental studies have been conducted to find out what characteristics the metal that makes up the second member should have. As a result, it was found that it is preferable to coat with a sprayed layer of a specific particle-dispersed reinforced metal composite material made of metal.

The present invention is based on the knowledge obtained as a result of various experimental studies conducted by the inventors of the present invention, and provides a sliding member comprising a first member and a second member that are in contact with each other and slide relative to each other. A specific particle-dispersion-reinforced metal composite material in which the first member is made of a fiber-reinforced metal composite material with alumina-silica fibers as reinforcing fibers and an aluminum alloy or magnesium alloy as a matrix, and the second member is made of a particle-dispersion-reinforced metal composite material. The object of the present invention is to provide a sliding member which is made of a metal coated with a thermally sprayed layer, and which has excellent wear resistance and seizure resistance.

Means for Solving the Problems According to the present invention, the above-mentioned object is achieved by providing a sliding member consisting of a first member and a second member that abut each other and slide relative to each other; The sliding surface portion of one member relative to at least the second member has an AI of 40vt% or more AI 203
, the rest is essentially sIo! ! Volume fraction 3~
It is made of a fiber-reinforced metal composite material with 30% alumina-silica fibers as reinforcing fibers and an aluminum alloy or magnesium alloy as a matrix, and at least the sliding surface portion of the second member relative to the first member has Hv.
A particle dispersion reinforced metal whose reinforcement is metal oxide particles having a hardness of 800 or higher and a volume fraction of 25 to 85%, and whose matrix is a metal selected from the group consisting of iron, nickel, and alloys containing these as main components. This is accomplished by a sliding member made of metal coated with a sprayed layer of composite material.

Effects and Effects of the Invention According to the present invention, the sliding surface of the first member relative to at least the second member is reinforced with alumina-silica fibers having a volume ratio of 3 to 30%, and an aluminum alloy or a magnesium alloy is used as a matrix. The sliding surface of the second member relative to at least the first member is made of iron reinforced with metal oxide particles having a volume ratio of 25 to 85% and having a hardness of Hv800 or more. It is made of metal coated with a thermal sprayed layer with excellent sliding properties of a particle dispersion strengthened metal composite material whose matrix is a metal selected from the group consisting of nickel, nickel, and alloys containing these as main components. As is clear from the results of experimental research conducted by the inventors of the present application, which will be described later, it is possible to obtain a sliding member with excellent wear resistance and seizure resistance of the two members.

According to the results of experimental research conducted by the inventors of the present application, metal oxide particle dispersion-reinforced metal composite materials are materials suitable for constructing sliding members in combination with the above-mentioned fiber-reinforced metal composite materials. , the hardness of the metal oxide particles used is Hv
If it is less than 800, the wear resistance of the sprayed layer will be insufficient, and as a result, the amount of wear on the second member will increase. Therefore, in the present invention, metal oxide particles having a hardness of Hv800 or more, particularly Cr2O3 particles, T i O! ! Particles, ZrO2 particles, All! Particles selected from the group consisting of 03 particles and mixtures of two or more of these particles are used. If the hardness of the metal oxide particles is extremely high, the aggressiveness of the sprayed layer may increase and the amount of wear on the first member will increase. It is considered that the hardness is preferably about Hv2500 or less.

Also, according to the results of experimental research conducted by the inventors of the present application,
If the volume fraction of metal oxide particles in the particle dispersion-strengthened metal composite material constituting the sprayed layer is small, the wear resistance of the sprayed layer cannot be ensured to a sufficient value, and conversely, the metal oxide particles When the volume fraction of the particles is a high value, the aggressiveness of the sprayed layer increases and the amount of wear of the first member becomes a high value. Therefore, in the present invention, the volume fraction of metal oxide particles in the particle dispersion-strengthened metal composite material is set to 25 to 8,596%, preferably 30 to 80%.

Furthermore, if the size of the metal oxide particles is too large, abnormal wear may occur on the first member, or the amount of wear on the first member may become excessive due to particles falling off. If the size of the particles is too small, it is difficult to sufficiently improve the wear resistance of the sprayed layer, and it is also difficult to form a sprayed layer of particle dispersion reinforced metal composite material on the surface of the second member by thermal spraying. If very fine metal oxide particles are used, the metal oxide particles will melt into the matrix and the material constituting the sprayed layer will no longer be a suitable particle dispersion reinforced metal composite material. Therefore, in the present invention, the size of the metal oxide particles before thermal spraying is 5 to 100μ, especially 1
The size of the metal oxide particles in the sprayed layer is preferably about 0 to 60 μm, and the size of the metal oxide particles in the sprayed layer is preferably about 2 to 50 μm, particularly about 5 to 20 μm.

Also, according to the results of experimental research conducted by the inventors of the present application,
When the sliding surface of the second member is made of metal coated with a sprayed layer of particle dispersion reinforced metal composite material as described above, even if the surface roughness of the sprayed layer is relatively large, , the amount of wear of the first and second members can be reduced compared to the case where the second member is made of metal that is not coated with the sprayed layer, but the surface roughness of the sprayed layer is especially 1.2μ
When Rz or less, the amount of wear of the two members can be suppressed to a small value. According to another detailed feature of the invention, therefore, the surface roughness of the sprayed layer is set to less than 1°2 μRz.

Also, according to the results of experimental research conducted by the inventors of the present application,
By electrolytically etching the sliding surface of the first member, a part of the alumina-silica fibers are exposed on the sliding surface, and a recess is formed on the surface of the matrix between the alumina-silica fibers exposed on the sliding surface. In this case, the wear resistance and seizure resistance of the first and second members can be further improved. Therefore, according to yet another detailed feature of the present invention, the sliding surface of the first member is electrolytically etched so that a part of the alumina silica fiber is exposed on the sliding surface. It is used with depressions formed on the surface of the matrix between the alumina-silica fibers exposed to the moving surface.

Furthermore, if the thickness of the sprayed layer of the particle dispersion reinforced metal composite material is too small, the sprayed layer will disappear due to wear and the metal of the second member will be exposed, and conversely, the thickness of the sprayed layer will be too large. In this case, the time required for thermal spraying becomes longer, more particle dispersion reinforced metal composite material is used than necessary, and the cost of the sliding member increases. Therefore, the thickness of the sprayed layer of the particle dispersion-strengthened metal composite material should be 5 μ or more, especially 5 to 2
00μ, more preferably 10 to 150μ.

In one specific embodiment of the invention, the sliding member is an internal combustion engine, the first member is a cylinder liner,
The second member is the piston ring.

In another specific embodiment of the present invention, the sliding member is an internal combustion engine, the first member is a piston,
The second member is the piston ring.

When the Al2O3 content of the alumina-silica fibers as reinforcing fibers of the composite material of the inner cylinder member, that is, the fibers mainly composed of Al2O3 and 5t02, is less than 40 wt%, the wear resistance of the composite material cannot be sufficiently improved. cannot be improved. Therefore, in the present invention, the AI 203 content is 40
wt% or more of alumina silica fiber is used. The alumina silica fibers may be either long fibers or short fibers, and have an average fiber diameter of 100 μm or less, particularly 1 to 4 μm.
It is preferable that it is about 0μ.

Furthermore, if the volume percentage of the alumina-silica fiber is less than 5%, especially less than 3%, the wear resistance of the fiber-reinforced metal composite material cannot be sufficiently improved; When the rate exceeds 15%, especially 30%,
The amount of wear on the fiber reinforced metal composite material and the second member increases. Therefore, the volume fraction of alumina silica fiber is 3 to 30
%, preferably 3 to 15%. Furthermore, the orientation of the alumina silica fibers may be any orientation such as unidirectional orientation, two-dimensional random orientation, three-dimensional random orientation, etc.
In particular, in the case of unidirectional orientation and two-dimensional random orientation, it is preferable that the sliding surface is set to be as perpendicular to the unidirectional orientation or the two-dimensional random orientation plane as possible, or at an angle close to this.

Further, the alloy mainly composed of Fe and the alloy mainly composed of Ni as the matrix of the metal oxide particle dispersion strengthened metal composite material of the sprayed layer of the second member are carbon steel (for example, JI
S standard SWRMI~4), low alloy steel (e.g. JIS standard 5UJ2), stainless steel (e.g. JIS standard 5US3)
04), Ni-Cr alloy, N1 self-fluxing alloy (e.g. 72
%N1-3%B-4%S1-20%Co).

Furthermore, the metal constituting the second member may be any metal as long as it can be coated with the above-mentioned particle dispersion reinforced metal composite material by thermal spraying.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will be explained in detail below by way of example embodiments with reference to the accompanying figures.

Example 1 A sliding member consisting of two members that come into contact with each other and slide relative to each other, one of which is a fiber-reinforced metal composite with alumina-silica fiber as a reinforcing fiber and an aluminum alloy as a matrix. Abrasion tests and seizure tests were conducted on sliding members made of metal, the other member being made of metal coated with a sprayed layer of particle dispersion-strengthened metal composite material. This will be explained in comparison with wear tests and seizure tests conducted on sliding members made of a combination of materials.

First, alumina-silica fibers (55 wt% A+, 03, the remainder substantially Sin) having an average fiber diameter of 2.8μ and an average fiber length of 6a+a+ are oriented in a substantially three-dimensional random manner to form a fiber molded body, By high-pressure casting (temperature of molten metal 730°C, pressure applied to molten metal 500 kg/am2) using the fiber molded body, aluminum alloy (J
A composite material having IS standard AC8A) as a matrix was manufactured. Then, the size of this composite material is 16X6X1
A large number of flat test pieces were prepared, each having a diameter of 0 mm and one surface (16×6a+w) serving as the test surface. For comparison purposes, a large number of flat plate test pieces were prepared that were made only of aluminum alloy (JIS standard AC8A) that was not reinforced with alumina-silica fibers and had the same dimensions as the above-mentioned flat plate test pieces.

Next, these flat test pieces were sequentially set in a friction and wear tester, and the outer diameter of the mating member was 35+++n and the inner diameter was 3011.
1111% width 10tm spheroidal graphite cast iron (JIS Kiraku FC
D70) or spheroidal graphite cast iron (JISm Raku FCD70) coated with a 150μ thick plasma sprayed layer, the test pieces were brought into contact with the end face of a cylindrical test piece made of spheroidal graphite cast iron (JISm Raku FCD70), and lubricating oil (Castle Motor oil 5W-30
), load 60 kg, rotation speed 160 rp.
A wear test was conducted by rotating a cylindrical test piece for 1 hour at a+.

The combinations of the flat plate test piece and the cylindrical test piece are as shown in Table 1 below. The parts before and after the symbol - in , respectively indicate the matrix and metal oxide particles of the particle dispersion-strengthened metal composite material constituting each sprayed layer, and the metal oxide particle content and particles of each sprayed layer. The average particle diameters were 40vol% and 10μ, respectively. Each thermal spray layer was applied by cleaning one end surface of the cylindrical test piece by shot blasting, and then using a plasma spraying device (3MB) manufactured by METCO, plasma spraying was performed under the conditions shown in Table 2 below. It was formed by doing the following. In addition, in Table 1, the unit of surface roughness of the sprayed layer of the cylindrical test pieces of combinations A1 to A5 is μRz, and the surface roughness of the surface to be tested of the cylindrical test pieces of other combinations is all 1.2 μRz.
The surface roughness was adjusted by changing the grinding conditions for the test surface.

Table 1 (Part 1) Table 1 (Part 2) Table 1 (Part 3) Table 2 (Plasma spraying conditions) A Gas flow rate: 23001/hr H2 gas flow fi: 450 no/br Supply current: 450 to 500 A Mixed powder Average particle size: 20μ Supply amount of mixed powder: 40g/mln Spraying distance: 210
0a+1n The results of this wear test are shown in FIG. Furthermore, in Figure 1,
The upper half represents the wear amount (wear scar depth μ) of the flat plate test piece, and the lower half represents the wear amount (wear loss mg) of the cylindrical test piece, which is the counterpart material (see Figures 2 to 3 below). The same applies to Figure 5).

From FIG. 1, it can be seen that the wear holes of the flat plate test pieces of the combinations λ14 to A I9 are very high values, and especially in the case of the combination A I4, the wear amount of the cylindrical test pieces is also a relatively high value. Further, the wear amount of the flat plate test pieces of combinations A and -A is much smaller than that of the flat plate test pieces of combinations A14 to A I9, and these combinations A and -AI=
It can be seen that the wear amount of the cylindrical test piece is much smaller than that of combinations A I3 and A I4. Thus, the combinations A1 to AI of flat test pieces made of aluminum alloy reinforced with alumina-silica fibers and cylindrical test pieces made of spheroidal graphite cast iron coated with a sprayed layer of metal oxide particle dispersion-strengthened metal composite material! ! In the case of , the wear amount of both the flat plate test piece and the cylindrical test piece is smaller than that of other combinations, and in particular, from the wear test results of combinations 81 to A5, the surface roughness of the sprayed layer is 1. It can be seen that it is preferable that it is 2 μRz or less.

In addition, test piece combinations 81 to A I shown in Table 1 above
Regarding 9, lubricating oil (castle motor oil 5W-30) at room temperature was supplied to the contact area between the flat plate test piece and the cylindrical test piece, and the cylindrical test was performed on the flat plate test piece while rotating the cylindrical test piece at a rotation speed of 1000 rpm. The suppression load of the piece is 10
kg to 700 kg, and a seizure test was conducted to measure the maximum seizure load.

As a result of this test, combination A, -A12) especially combination A3
-A12 had a higher seizure limit load than any other combination, and it was therefore confirmed that these combinations also had excellent seizure resistance.

Example 2 In the same manner as in Example 1 above, alumina-silica fibers (alumina-silica fibers used in Example 1) were oriented in a substantially three-dimensional random manner at a volume fraction of 8%. The same as silica fiber) is used as the reinforcing fiber, and magnesium alloy (JI
A composite material with S standard MC2) as a matrix was cast under high pressure (temperature of molten metal 700°C, pressure applied to the molten metal 800°C).
kg/am''), and a large number of flat test specimens with the same dimensions as in Example 1 were prepared from the composite material.

Next, with respect to these flat test pieces, a wear test and a seizure test were conducted using the test piece combinations shown in Table 3 below in the same manner and under the same conditions as in Example 1. The cylindrical test pieces of combinations B1 to B3 shown in Table 3 below were prepared in the same manner and under the same conditions as combinations A2) A3 and A5 shown in Table 1 above, and the cylindrical test pieces of combinations 84 to B11 were Each of the test pieces had a sprayed layer formed and the surface roughness adjusted in the same manner and under the same conditions as combinations A6 to A8, and the surface roughness of the test surface of the cylindrical test piece of combination B7 was 1.
．． It was 2μRz.

Table 3 The results of this wear test are shown in Figure 2. From FIG. 2, it can be seen that the combination B! compared to the combination BT! ~The wear amount of B6 is a low value for both the flat plate test piece and the cylindrical test piece,
In particular, the wear amount of combinations 82 to B is lower than that of combination B1 for both the flat plate test piece and the cylindrical test piece. The combination with spheroidal graphite cast iron coated with a sprayed layer of oxide particle dispersion reinforced metal composite material also has excellent wear resistance, and the surface roughness of the sprayed layer is preferably 1.2 μRz or less. I understand.

Also, although not shown in the figure, as a result of the seizure test, a spherical shape coated with a sprayed layer of a composite material made of a magnesium alloy reinforced with alumina-silica fibers and a metal composite material reinforced with dispersion of metal oxide particles was found. It was confirmed that the combination with graphite cast iron also has excellent seizure resistance.

Example 3 Alumina fibers (95 wt% A+203, remainder substantially 8102) oriented in a substantially three-dimensional random manner at a volume ratio of 6% in the same manner as in Example 1 above. Average fiber diameter. 3.2 μ, average fiber length 8 ma+) as reinforcing fibers, aluminum alloy (JIS standard A D C10,)
High-pressure casting of a composite material with a matrix of
2), and a large number of flat test pieces having the same dimensions as in Example 1 were prepared from the composite material.

Next, these flat test pieces were subjected to wear tests and seizure tests using the test piece combinations shown in Table 4 below in the same manner and under the same conditions as in Example 1. The cylindrical test pieces of combinations 01 to C3 shown in Table 4 below were prepared in the same manner and under the same conditions as the doffing combinations A2, A3, and A5 shown in Table 1, and the cylindrical test pieces of combinations 04 to Ca were Each of the test pieces had a sprayed layer formed and the surface roughness adjusted in the same manner and under the same conditions as combinations A8 to AS, and the surface roughness of the test surface of the cylindrical test piece of combination C7 was 1.
．． It was 2 μRz.

Table 4 The results of this wear test are shown in Figure 3. From FIG. 3, compared to the case of combination cT, the wear amount of combinations 01 to C6 is a lower value for both the flat plate test piece and the cylindrical test piece,
In particular, the wear amount of combinations 02 to C6 is lower than that of combination CI for both the flat plate test piece and the cylindrical test piece. The combination with spheroidal graphite cast iron coated with a sprayed layer of dispersion-strengthened metal composite material also has excellent wear resistance, and the surface roughness of the sprayed layer is 1.
It can be seen that it is preferable that it is 2 μRz or less.

Also, although not shown in the figure, as a result of the seizure test, spheroidal graphite cast iron was coated with a composite material made of aluminum alloy reinforced with alumina fibers and a sprayed layer of a metal composite material reinforced with dispersion of metal oxide particles. It was confirmed that the combination with

Example 4 Alumina fibers (same as the alumina fibers used in Example 3) were oriented in a substantially three-dimensional random manner at a volume fraction of 6% in the same manner as in Example 1 above. ) as reinforcing fibers and a magnesium alloy (JIS standard MC2) as a matrix by high-pressure casting (molten metal temperature 7
00℃, pressurizing force on molten metal 800'kg/ati
2), and a large number of flat test pieces having the same dimensions as in Example 1 were prepared from the composite material.

Next, a wear test and a seizure test were conducted on these flat test pieces in the same manner and under the same conditions as in Example 1 using the combinations of test pieces shown in Table 5 below. The cylindrical test pieces of combinations D1 to D3 shown in Table 5 below were prepared in the same manner and under the same conditions as the combinations A2, A3, and As shown in Table 1, respectively, and the cylindrical test pieces of combinations D4 to D6 were Each of the test pieces had a sprayed layer formed and the surface roughness adjusted in the same manner and under the same conditions as combinations A6 to A8, and the surface roughness of the test surface of the cylindrical test piece of combination BT was 1.
．． It was 2 μRz.

Table 5 The results of this wear test are shown in Figure 4. From FIG. 4, compared to the case of combination DT, the wear amount of combinations D1 to Dfl is a lower value for both the flat plate test piece and the cylindrical test piece, and in particular, the wear amount of combinations D2 to Dδ is a lower value for both the flat plate test piece and the cylindrical test piece. All of the cylindrical test pieces had lower values than the combination Dl, and therefore, the spheroidal graphite coated with a sprayed layer of a composite material made of a magnesium alloy reinforced with alumina fibers and a metal composite material reinforced with dispersion of metal oxide particles. The combination with cast iron has excellent wear resistance, and the surface roughness of the sprayed layer is 1.2μ.
It can be seen that it is preferable that Rz or less.

Although not shown in the figure, as a result of the seizure test, spheroidal graphite cast iron was coated with a composite material made of magnesium alloy reinforced with alumina fibers and a sprayed layer of a metal composite material reinforced with dispersion of metal oxide particles. It was confirmed that the combination with

The same wear test as in Examples 2 to 4 was also conducted on a cylindrical test piece in which the matrix of the sprayed layer was Ni.
Results similar to those of Examples 2 to 4 were obtained.

Example 5 Fe powder and ZrO when performing plasma spraying on the surface of a cylindrical test piece! ! By changing the mixing ratio with the powder, the ZrO2 particle content in the sprayed layer of the cylindrical test piece was reduced to Ovo19g.
, 10vo1%, 25vo1%, 40vo1%, 60v
Plasma spraying was performed in the same manner and under the same conditions as in Example 1 above to obtain 01%, 85vo1%, and 100vo1%, and the same flat plate test as the flat plate test pieces of combinations A1 to A I3 of Example 1 was performed. A wear test was conducted using the piece under the same procedure and conditions as in Example 1. The results of this wear test are shown in FIG.

From Figure 5, the wear amount of the flat plate test piece is
The value is high when the ZrO2 content is less than 0 VO1% and more than 80 VOI%, especially when it is less than 25 VO1% and more than 85 VOI%, and the wear amount of the cylindrical test piece is higher when the ZrO2 content is less than 30 VO1%, especially 25V.

It can be seen that the value is high when it is less than 1%. This result was obtained because when the ZrO2 content is low, the wear resistance of the sprayed layer becomes insufficient and the amount of wear increases. In areas where the amount of wear is increased and the ZrO2 content is high,
The hardness of the sprayed layer becomes too high, and the ZrO2
This is thought to be due to particles becoming easier to fall off. From the results shown in Figure 5, the ZrO2 content is between 25 and 85.
It can be seen that vol 1%, particularly 30 to 80 vol %, is preferable.

When the same wear test as in this example was conducted using the same flat test piece as in Examples 2 to 4, results similar to those shown in FIG. 5 were obtained.

Furthermore, from Example 1, Cr203, TiO2)Al2O3
Since Z r 02 is also a metal oxide that performs the same function as Z r 02, it is presumed that similar results will be obtained when these particles are used as the metal oxide particles.

Example 6 Alumina-silica tJAN, which is the same as the alumina-silica fiber used in Example 1, was formed into a fiber molded body in which the fibers were oriented in a substantially three-dimensional random manner, and the fiber molded product was used in the experiment. By high-pressure casting (temperature of molten metal 730℃, pressure applied to molten metal 500 kg/cm2), the volume ratio is 8.
% of alumina-silica fibers as reinforcing fibers and an aluminum alloy (JIS standard ADT4) as a matrix. Next, from this composite material, the outer diameter is 25.6
Eight cylindrical test pieces having dimensions of mttr, inner diameter 20.0 mm, and length 16 mm with one end face as the test surface were formed, and the surface roughness of the test surface of each test piece was reduced to 0.0 by grinding. 6
Finished to μRz.

Next, recesses were formed on the surface of the matrix of the test surface of the six cylindrical test pieces by electrolytic etching using an aqueous nitric acid solution. Fig. ff16 is a schematic diagram showing a cross section near the test surface of a test piece formed by peeling, and in the figure, 21 indicates alumina-silica fibers as reinforcing fibers, and 22 indicates an aluminum alloy as a matrix. 23 indicates a recessed portion.

In this case, by appropriately setting the electrolytic etching conditions, the average value of the depth Dl of the recesses 23 appearing on any cross section of the surface to be tested is 1.8μ, and the ratio of the depth to the opening diameter of the recesses 23 is obtained. That is, the average value DI /Wl of the ratio of the depth Dl to the opening length Wl of the recess 23 appearing in an arbitrary cross section of the test surface is 0.02, and the alumina-silica fiber is smaller than the surface 24 of the composite material. The average value H1 of the exposed height Hl of is 0.8μ, and the area ratio of the recesses, that is, the percentage of the total ratio of the opening length Wl of the recesses 23 to the base length of an arbitrary cross section of the composite material is Six cylindrical specimens, representing 20%, were formed.

Next, these cylindrical specimens were subjected to electrolytic etching, and cylindrical specimens made of a composite material in which no electrolytic etching was performed, and therefore the depth of the recess, the exposed progeny of the alumina-silica fibers, and the area ratio of the recess were 0. The test pieces were sequentially set in a friction and wear tester, and were made of spheroidal graphite cast iron (JIS standard FCD70) and had a size of 30 x 30 x 5 mm.
One surface (30 x 30 av) of the test piece is brought into contact with the surface to be tested of a flat test piece, and the contact area of the test piece is filled with lubricating oil (Castle Motor Oil 5AE3) at room temperature.
0) and rotating the cylindrical test piece at a rotational speed of 11,000 rpm, increasing the suppressing load of the cylindrical test piece against the flat plate test piece from 10 kg to 700 kg, thereby measuring the seizure limit load. I did it.

The combinations of cylindrical test pieces and flat plate test pieces in this seizure test were as shown in Table 6 below.

In addition, the surface roughness of the tested surface of each flat test piece was 1°2μ.
Rz, and the sprayed layers of particle dispersion reinforced metal composite materials in the flat test specimens of combinations El and E4 to E8 were each formed by plasma spraying under the same conditions as shown in Table 2 above.

Figure 7 shows the results of the seizure test shown in Table 2. From Figure 7, the seizure limit load of combination El is combination E! ! The maximum seizure load of combinations E4 to Ea (no seizure occurs) is much higher than the maximum seizure load of combinations E2 and E3. A combination of a composite material made of a reinforced aluminum alloy and spheroidal graphite cast iron coated with a sprayed layer of metal oxide particle dispersion reinforced metal composite material, and an electrolytic etching made of an aluminum alloy reinforced with alumina-silica fibers. It can be seen that the combination of this composite material and spheroidal graphite cast iron coated with a sprayed layer of metal oxide particle dispersion reinforced metal composite material has excellent seizure resistance. Furthermore, especially from the comparison between combinations El and E4, it was found that the seizure resistance could be further improved by subjecting the composite material to electrolytic etching to expose the reinforcing fibers and forming recesses between the reinforcing fibers on the surface of the composite material. I understand.

Although not shown in the plan view, when a wear test was conducted on the combinations of test pieces shown in Table 6 above in the same manner as in Example 1, combinations El and E4 to Ea, especially It was confirmed that combinations E4 to E days were also excellent in wear resistance.

Embodiment 7 FIG. 8 is an illustrative longitudinal sectional view showing a specific embodiment of a sliding member according to the present invention, which is a combination of a piston and a piston ring for an internal combustion engine, and FIG. 9 is an illustrative diagram showing the main parts thereof. Fig. 10 is an illustrative partial longitudinal sectional view showing an enlarged piston ring (top ring).

In these figures, 1 is a piston, which is made of aluminum alloy (JIS standard AC8A). On the side outer circumferential surface 2 of the piston 1 are two rings that receive compression rings 4 and 5 that prevent combustion gas from leaking from the combustion chamber of the internal combustion engine through the space between the piston 1 and the cylinder wall surface of the cylinder block 3. Grooves 6 and 7 and a ring groove 9 for receiving an oil ring 8 for scraping off excess oil are formed.

In the illustrated embodiment, the lower surface 11 of the top ring groove 6 is closer to the piston head 10 along the side outer peripheral surface 2 of the piston 1.
The lower part is reinforced with a fiber molded body in which the same alumina-silica fibers as the alumina-silica fibers used in Example 1 are oriented in a substantially three-dimensional random manner at a volume ratio of 8%. The other parts of the piston 1 are made of a composite material 12 having an aluminum alloy (JIS standard AC8A) as a matrix. This composite material 1
2 defines the wall surface of the top ring groove 6 that receives the top ring 4, and also defines a part of the top land 13 and the second land 14 in the portion exposed to the side outer peripheral surface 2 of the piston. .

In addition, such a piston is made by placing a fiber molded body on the bottom wall of a mold cavity of a mold for casting the piston, pouring molten aluminum alloy into the mold, and fitting the piston into the mold in a fluid-tight manner. The aluminum alloy is solidified while being pressurized by a plunger to form a piston rough material, which is then heat treated (T
6 processing), it is processed to the specified dimensions, and then the ring groove 6.
7.9.

Abutting against the piston 1 as described above and relatively JfI
The top ring 4 is made of stainless steel (JIs standard 5).
US420J2), and although not shown in the figure, the lower surface 17 is made of Cr2O3 particle-dispersed F with a thickness of 20μ.
e sprayed layer (Cr203 containing H40vo1%, Cr2O
3 particles average particle size 10μ, surface roughness 0.8μRz),
Sprayed layer of Tiop particle-dispersed Fe (T i 02 particle content 60vo1%, average particle size of Ti 02 particles 10μ,
Surface roughness 0.8μRZ) or ZrO2 particle dispersion F
Thermal sprayed layer of e (Zr02 particle containing ff145vo1%, Z
rO2 particles average particle size 15μ, surface roughness 0.8μRz)
covered with. In particular, the illustrated embodiment is configured as a 7° keystone ring, and a molybdenum sprayed layer 1 is provided on the sliding surface of the cylinder block 3 with the cylinder wall surface.
5 was formed.

The piston and piston ring configured as described above are
Built into a cylinder 4-stroke diesel engine, the engine speed is 5.
5 under test conditions of 400rpa+ and full engine load.
A durability test was conducted for 00 hours. For comparison purposes, a piston ring made of spheroidal graphite cast iron (JIS standard FCD70) whose lower surface 17 is not coated with a sprayed layer of a metal composite material reinforced by dispersion of metal oxide particles was also tested under the same conditions. We conducted a test.

As a result of the test, in the case of a piston ring made of spheroidal graphite cast iron whose lower surface 17 is not coated with a sprayed layer of metal composite material reinforced by dispersion of metal oxide particles, the amount of wear on the lower surface 11 of the ring groove is 20μ, The amount of wear on the lower surface 17 of the piston ring was 15μ, whereas in the case of a piston ring whose lower surface 17 was coated with a sprayed layer of a metal composite material reinforced with dispersion of metal oxide particles, the amount of wear on the lower surface 11 of the ring groove was The amount of wear is 3°0μ, and the amount of wear on the lower surface 17 of the piston ring is 0.
5μ, and therefore, it was recognized that the pistons and piston rings of the examples had much better wear resistance than the comparative examples.

Example 8 The alumina-silica fibers and aluminum alloy used in Example 1 above were reinforced with 10% volume fraction alumina-silica fibers oriented in a substantially three-dimensional random manner. A cylinder liner made of aluminum alloy is manufactured by high-pressure casting (molten metal temperature 730°C, pressure applied to the molten metal 500 kg/am2), and the cylinder liner is cast by gravity casting to produce a 4-cylinder, 4-stroke cylinder liner with a cylinder bore diameter of 80 mm. Four cylinder blocks for internal combustion engines are formed, and the cylinder bore of each cylinder block is honed to a surface roughness of 0.6μ.
Finished in Rz.

Next, it is made of spheroidal graphite cast iron (JIS standard FCD70), and the radially outer peripheral surface is plasma sprayed to a thickness of 15 mm.
Sprayed layer of Fe dispersed with 0μ Cr2O3 particles (Cr203 content Q40vo1%, average particle size of Cr2O3 particles, 10μ
, surface roughness 1.0 μRz), thermal sprayed layer of TiO2 particle-dispersed Fe (containing TiO2 particles 60vo1%, Ti
O! Average particle diameter: 4゜μ, surface roughness: 1.0μRz)
, or a sprayed layer of ZrO2 particle-dispersed Fe, CZrO2 particle content ff145vo1%, average particle size of ZrO2 particles 45μ
, a piston ring coated with a surface roughness of 1°0 μRz), and a piston as a comparative example that is not coated with a sprayed layer of a metal composite material dispersion-strengthened with metal oxide particles made of spheroidal graphite cast iron (JIS standard FCD70). Prepare the ring
These piston rings and the above-mentioned cylinder block were combined into a 4-cylinder 4-stroke diesel engine, and the engine rotation speed was 6000 rpm.

A high-speed durability test was conducted for 200 hours under full engine load.

As a result of this test, when the piston ring was the piston ring of the comparative example, scuffing occurred in the cylinder bore and the wear amount of the cylinder bore was as high as 30μ, whereas the piston ring was found to have dispersion of metal oxide particles. In the case of piston rings made of spheroidal graphite cast iron coated with a sprayed layer of reinforced metal composite material, there is no scuffing in the cylinder bore, and the amount of wear on the outer peripheral surface of the piston ring and cylinder bore is 2.0μ or less. This is a very small value, and it was therefore recognized that the cylinder liner and piston ring of the example had much better wear resistance than the comparative example.

Although the present invention has been described above in detail with reference to several embodiments, the present invention is not limited to these embodiments, and various other embodiments are possible within the scope of the present invention. It will be clear to those skilled in the art that

[Brief explanation of the drawing]

1 to 5 are graphs showing the results of the wear tests of Examples 1 to 5, respectively, and FIG. 6 is a graph showing the surface portion of the fiber-reinforced metal composite material constituting the first member of the sliding member according to the present invention. A schematic diagram showing a cross section, FIG. 7 is a graph showing the seizure test results of Example 6, and FIG. 8 is a specific example of a sliding member according to the present invention applied to a combination of a piston and a piston ring. An illustrative longitudinal cross-sectional view showing the embodiment; FIG. 9 is an enlarged partial longitudinal sectional view showing the main parts of the embodiment shown in FIG. 8; and FIG. 10 is an enlarged view of the piston ring (top ring). FIG. 1... Piston, 2... Side outer peripheral surface, 3... Cylinder liner, 4... Top ring, 5... Second ring. 6...Top ring groove, 7...Second ring groove,
8...Oil ring, 9...Ring groove, 10...
Piston head, 11... Bottom surface of top ring groove, 1
2...Composite material, 13...Topland, 14...
・Second land, 15...Molybdenum sprayed layer, 17
... Bottom surface of top ring, 21 ... Alumina-silica fiber, 22 ... Aluminum alloy, 23 ... Concave portion, 24 ... Surface portion Applicant Toyota Motor Corporation Representative Patent Attorney Akashi Changki Fig. 1 (1□ Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Ward Fig. 7

Claims (6)

[Claims] (1) A sliding member consisting of a first member and a second member that are in contact with each other and slide relative to each other, and the sliding surface portion of at least the first member relative to the second member is 40W.
It is composed of a fiber-reinforced metal composite material in which the reinforcing fibers are alumina-silica fibers with a volume ratio of 3 to 30% having a composition of t% or more Al_2O_3 and the remainder substantially SiO_2, and the matrix is an aluminum alloy or a magnesium alloy. At least the sliding surface of the second member relative to the first member is reinforced with metal oxide particles having a hardness of Hv800 or higher and a volume ratio of 25 to 85%, and is made of iron, nickel, or an alloy containing these as main components. A sliding member made of a metal coated with a sprayed layer of a particle dispersion-strengthened metal composite material whose matrix is a metal selected from the group consisting of: (2) In the sliding member according to claim 1, the metal oxide particles are selected from the group consisting of Cr_2O_3 particles, TiO_2 particles, ZrO_2 particles, Al_2O_3 particles, and mixtures of two or more of these particles. A sliding member characterized by being made of selected particles. (3) The sliding member according to claim 1 or 2, wherein the thermal sprayed layer has a surface roughness of 1.2 μFz or less. (4) In the sliding member according to any one of claims 1 to 3, the sliding surface of the first member is electrolytically etched so that a portion of the alumina-silica fiber is removed. is exposed on the sliding surface, and a recess is formed on the surface of the matrix between the alumina silica fibers exposed on the sliding surface. (5) In the sliding member according to any one of claims 1 to 4, the sliding member is an internal combustion machine, the first member is a cylinder liner, and the second member is a cylinder liner. is a sliding member characterized by being a piston ring. (6) In the sliding member according to any one of claims 1 to 4, the sliding member is an internal combustion engine, the first member is a piston, and the second member is a piston. is a sliding member characterized by being a piston ring.