JPH02185942A - Sliding member for high-temperature use - Google Patents

Abstract

PURPOSE:To obtain a sliding member excellent in strength at high temp., wear resistance, and oxidation resistance by manufacturing a sliding member for high-temp. service used, e.g. for forming glass member by sintering the hard double borides of specific metals by the use of Ni, Mo, etc., as binding materials. CONSTITUTION:At the time of manufacturing a sliding member for high-temp. service for use, e.g. in press forming equipment and bending device for glass products, such as lens, pulverized powders of high-purity MoB, WB, Mo, Ni, etc., are subjected, together with organic solvents such as ethanol, to wet grinding by means of a ball mill, etc., and then to mixing. The resulting slurry is dried, compacted by means of mold press, etc., and sintered in vacuum or in a reducing atmosphere. By this method, the hard sintered material which contains a hard double boride phase of Mo2NiB2, W2NiB2, (Mo,W)2NiB2, etc., by 20-95wt.% and in which Ni and Mo are used as binding materials can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a member that slides at high temperatures and is used in press molding equipment, bending equipment, etc. for glass products.

[Conventional technology] In recent years, with the diversification of glass parts, more complex shapes, and demands for cost reduction, there has been a movement to directly press mold optical parts such as lenses, and to make front and rear windows for automobiles using the conventional method of gravity. There is an increasing movement towards manufacturing by bending instead of bending using a press or the like.

In order to make such a processing method industrially possible, five steps must be taken.
At temperatures above the glass softening point of 00 to 800 degrees Celsius, a device is required to accurately position glass materials and molds that are repeatedly processed. Therefore, it is necessary to use a material that does not cause seizing or galling at temperatures of 500 to 800 DEG C. and has excellent wear resistance for the sliding parts of such devices. In particular, the wear resistance is the first point to be kept in mind, since the abrasion powder causes defects in glass products. Furthermore, from the viewpoint of productivity, it is desirable that the material be resistant to temperature fluctuations as quickly as possible.

Conventionally, for such applications, Fe-N1-(:r steel, Co-based heat-resistant alloys such as Stellite, NL-based heat-resistant alloys such as Inconel, etc.) have often been used. Attempts have also been made to use ceramics such as silicon nitride, silicon carbide, and sialon from the viewpoint of wear resistance.

[Problems to be Solved by the Invention] However, even with these heat-resistant metal materials, when processing optical glass or float glass that has a relatively high softening point, galling and burn-in due to softening of the material occur. Various problems occur, such as surface wear, dimensional changes due to oxidation, and product defects due to wear particles and fallen oxide scale. Additionally, when using ceramics that have excellent strength and hardness at high temperatures, problems caused by oxidation and wear are reduced; however, when the mating material is metal, the mating material may be subject to increased wear and toughness. There are many problems such as breakage due to lack of thermal shock resistance and thermal shock resistance. Therefore, carbonization is applied to heat-resistant metal materials with excellent toughness and thermal shock resistance by plasma spraying or chemical or physical vapor deposition methods. Many attempts have been made to compensate for the drawbacks of both metals and ceramics by coating them with ceramic films made of silicon, alumina oxide, titanium carbide, etc. However, there is a problem with the films peeling off due to heating and cooling cycles, so it is not widely used. It has not yet been put into practical use.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and includes a Ni, Mo complex boride, a Ni, W complex boride, and a Ni,
Provided is a high-temperature sliding member comprising a sintered body comprising a hard phase mainly composed of one or more of Mo and W complex borides and a binder phase mainly composed of Ni and Mo. It is something.

The compound boride sintered body that is the material of the present invention is known as a boride cermet, and since it generally has a metal layer of a Ni-based alloy with a high coefficient of friction, it cannot be used at high temperatures. It was thought that it would be difficult to use it for exposed sliding parts.

The high temperature sliding member of the present invention can be obtained by the method described below. As raw materials, MoB, W B, ! i! o, N
Each powder of i is ground and mixed in an organic solvent such as ethanol using a rotary ball mill, a vibration mill, or the like. The obtained slurry is dried under reduced pressure or by spray drying, etc., and then pressure molded using a mold press, rubber press, etc., and heated to a temperature of 1000°C or higher in a vacuum or in a neutral or reducing atmosphere such as argon or hydrogen. , often 1100-1
Heating may be performed in a temperature range of about 500°C. The raw material powders used are not necessarily the above MoB, WB, Mo, Ni.
(, N1-B alloy, Mo,
A combination with each powder of W and Ni may be used. It is preferable to use raw material powder with as high a purity as possible, and it is also preferable that the particle size is as small as possible.

Specifically, it is preferable that the purity is 99% or more and the particle size is 10 μm or less.

When the mixed raw materials are sintered, they react with each other during the heating process, and finally, a hard phase that is mainly MoJiBz or WJi8g or (No, W)JiBz and a mainly Ni
and a bonded phase consisting of Mo.

It is preferable that the binder phase is distributed so as to surround the hard phase, and that the hard phases are not continuous with each other but are independent. Also,
The average particle size of the hard phase is preferably 10 μm or less. The reason why it is preferable that the microstructure of the binder phase has the above-mentioned form is that when the structure is as described above, the strength and toughness of the sintered body are improved.

The weight percent of the hard phase in the sintered body is preferably 20 to 95%,
Particularly preferred is 30 to 85%. The reason why the ratio of the hard phase in the sintered body is determined as above is that if the hard phase is less than 20% by weight, the hardness of the sintered body decreases when heated to a high temperature of 500°C to 800°C. is noticeable, causing burning with the mating material,
This is because galling tends to occur, and if the hard phase exceeds 95% by weight, the toughness of the sintered body decreases and the hard phase falls off during friction, making it easy to cause abrasive friction.

It is preferable that the ratio of the hard phase is within the above range and changed as appropriate depending on the usage conditions of the member. For example, at sliding parts where impact loads are applied, the ratio of the hard phase is reduced to increase toughness, and the load is For small areas that slide at high speeds, the proportion of hard phase is increased to increase hardness.

[Function] Complex boride, which is the main component of the sintered body constituting the high-temperature sliding member according to the present invention, is essentially.

Compared to Fe-NL-Cr steel, etc., the decrease in hardness and strength at high temperatures is small, and even when composited with a binder phase mainly composed of Ni-Mo, its properties are clearly exhibited. Therefore, when the member according to the present invention is subjected to sliding friction with another metal material member or a member made of the same material (coupling) at a high temperature of about 800° C., it is considered that the amount of wear of the member according to the present invention is reduced.

On the other hand, when a member with a high hardness undergoes sliding friction with a mating material of lower hardness at high temperatures, the amount of wear on the mating material side generally increases dramatically, often leading to the end of its life prematurely. However, the member according to the present invention has a lower hardness,
For example, in the case of sliding friction with Fe-Ni-Cr steel at high temperatures, the wear amount of the mating material Fe-N1-(:r steel is also small (
Become. Although the mechanism by which such a phenomenon occurs is not necessarily clear, 1.The geometrical shape of the complex boride, which is the hard phase in the high-temperature sliding member according to the present invention, is equiaxed and relatively rounded, In general, it does not cause much damage to the mating material, and since the bond between the hard phase and the binder phase is strong and the sintered body has high toughness, abrasive wear due to the hard phase falling off is less likely to occur. etc. are possible.

Furthermore, since the high-temperature sliding member according to the present invention has excellent oxidation resistance, dimensional changes in the member due to the formation and falling off of the oxidized layer are also small.

The properties of the high-temperature sliding member according to the present invention as described above are even better exhibited when the same materials are rubbed against each other. When the material of the present invention is used for the piston and cylinder of production became possible.

[Example] Hereinafter, the invention will be explained in detail with reference to Examples.

0 Example 1 MoB powder (purity 99.5%, average particle size 4.5 μm15
0% by weight, WB powder (purity 99.5%, average particle size 3.5
μm) 10% by weight, Mo powder (purity 99.9%, average particle size 0.8 μm) 5% by weight, Ni powder (purity 9
A sintered body was obtained by sintering in vacuum at a firing temperature of 1270° C. using 35% by weight of the powder (9.6%, average particle size 3 μm) as a raw material. A piston and a cylinder as shown in Fig. 1 are created by grinding this sintered body, rapidly heated to 800℃ in N2, and cooled by blowing a large amount of cooling N2 gas.No cracks occur after a thermal cycle test. After confirming that
It was subjected to the following tests.

After cooling by rubbing the copper plate back and forth 1000 times in N2 at 700°C, the clearance between the piston and the cylinder was measured.

As a result, the initial clearance of 15 μm reached 50 μm after 100 times of reciprocation.

0 Examples 2 to 7 Sintered bodies having the compositions shown in Table 1 were produced using the same process as in Example 1 at a firing temperature of 1150 to 1300°C.

In Examples 2 to 5, the piston and cylinder were made of the same material (common metal), and in Examples 6 to 7, the piston was made of the invention material, and the cylinder was made of Fe-Ni-Cr steel and Ni-Cr-Fe alloy. The initial clearance between the two was set at 15 μm, and the same wear test as in Example 1 was conducted, and the results shown in Table 1 were obtained.

0 Comparative Examples 1 to 2 A sintered body was fired at a temperature of 1150 in the same process as in Example 1.
In Comparative Example 1, the piston and cylinder were made of the same material, and in Comparative Example 2, only the cylinder was made of Fe-Ni-C.
When the same test as in Example 1 was conducted using R steel, the results shown in Table 1 were obtained.

Comparative examples 3 to 5 For comparison, a conventional material, Fe-Ni-Cr steel.

Pistons and cylinders were made of Ni-Cr-Fe alloy and Xialon, and the same tests as in Example 1 were conducted, and the results shown in Table 1 were obtained.

Effects of the Invention As described above, the high-temperature sliding member according to the present invention has excellent wear resistance, strength, and oxidation resistance at high temperatures, and is less aggressive to the mating material, so it always has a If used in sliding parts of equipment for molding glass components exposed to high temperatures of 800°C, stable operation of the equipment will be possible for a long period of time, and molded products will not be defective due to abrasion particles. significantly reduced. It is particularly suitable for molding optical glass.

That is, by using the high-temperature sliding member of the present invention, the precision of molded products is improved and the product yield is also improved.

[Brief explanation of the drawing]

FIG. 1 is a side cross-sectional view showing an outline of a high-temperature sliding wear test device. 1...Piston 2...Cylinder 3...
・Heating heater 4...Temperature measurement n1 fever? T1 vs 5...
·Air cylinder

Claims (2)

[Claims] (1) Ni, Mo complex boride, Ni, W complex boride, and Ni
A high-temperature sliding member comprising a sintered body consisting of a hard phase mainly composed of one or more of complex borides such as , Mo, and W, and a binder phase mainly composed of Ni and Mo. (2) The high temperature sliding member according to claim 1, wherein the weight percentage of the hard phase in the sintered body is 20 to 95%.