JPS6033794B2 - sliding member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sliding member in which the surface of a base is coated with silicon carbide by physical vapor deposition.

Conventionally, there are sliding parts used in mechanical industry fields such as mechanical seals, bearings, turbines, pump parts, etc., where a silicon carbide film is directly formed on a carbon substrate. .

However, since the base is made of carbon, its mechanical strength (particularly Young's modulus) is lower than that of silicon carbide, which is the coating, so when used under harsh conditions, the carbon base may suffer from distortion or other disadvantages. For this reason, when a silicon carbide film formed as a film is intended to be widely used in industrial applications as a sliding part, the actual situation is that it is severely restricted in terms of the scope of application such as load conditions. there were. Furthermore, in recent years, due to the rise in the price of carbon materials, it has become inappropriate to provide inexpensive sliding members to the industrial market. Therefore, the inventors focused on using cheap alumina (Aso 203) as a base, and by coating silicon carbide on the alumina base, they created a cheap silicon carbide composite with high mechanical strength. A sliding member consisting of the following can be expected. However, with the conventional chemical vapor deposition method, it is technically difficult to coat silicon carbide due to the high deposition temperature and the destruction of the alumina substrate structure due to the reducing action of hydrogen, which is a carrier gas. The present invention has been developed in view of the above circumstances, and has a structure in which the alumina base and the silicon carbide coating layer are extremely firmly bonded, so that no internal stress is generated in the silicon carbide coating layer, and moreover, it has excellent sliding properties. An object of the present invention is to provide a sliding member having the following features. The present invention will be explained in detail below. When forming a silicon carbide coating layer on an alumina substrate, in order to bond these dissimilar materials together, it is necessary to create a structure that can eliminate as much as possible defects caused by hot air tension differences, and a structure that does not generate internal stress. It doesn't fall apart.

For this reason, it is very effective if a metal coating layer is previously provided on the surface of the alumina substrate on which the silicon carbide coating layer is to be applied, that is, so-called metallization is applied to the surface of the alumina substrate. This metallizing material is intended to be an alloy of iron and nickel, molybdenum, manganese, or an alloy thereof. In particular, in the present invention, it is preferable to use molybdenum, an alloy of manganese and molybdenum, etc., which have the same crystal system as silicon carbide. A silicon carbide coating layer suitable for use as a tiered member is formed on this metallized alumina base by physical vapor deposition. This physical vapor deposition method includes ion plating method,
There are vacuum evaporation methods, sputtering methods, etc., and although it may be possible to obtain the sliding member according to the present invention using these physical vapor deposition methods, the sputter method, which allows low-temperature evaporation and has good controllability, is preferable. Yes, especially when the deposition rate is 5 to 1M
Because of the speed of sound, magnetron sputtering is the most suitable method. According to this sputter deposition, the thickness required for the driving member is 5.
A silicon carbide coating layer with a thickness of 0 mm or more can be freely formed, and can be deposited at an extremely low temperature of 500 to 1000 oo, so that no internal stress or distortion occurs in the silicon carbide coating layer. Therefore, a stable and dense silicon carbide coating layer is produced. Moreover, since the vapor deposition is performed on the alumina substrate that has been subjected to metallization, the silicon carbide and metal are well bonded, and the peeling phenomenon that occurs when silicon carbide is directly vapor deposited on alumina, for example, can be completely eliminated, making it an excellent product. A sliding member was obtained. Next, the present invention will be further explained based on illustrative drawings.

FIG. 1 shows a sliding member according to the present invention, and is an example intended for a sealing ring of a mechanical seal.

The base body 2 of this emotional part 1 is made of alumina (A-203).

Reference numeral 3 denotes a metal coating layer, which is provided by metallizing the surface portion of the alumina substrate to be coated with silicon carbide.

4 is a silicon carbide coating layer.

This silicon carbide coating layer 4 is formed by sputter deposition, which is dense, nonporous, and homogeneous. In the sliding member 1 having such a structure, the alumina base 2 and the silicon carbide coating layer 4 are firmly joined by the metal coating layer 3, and the difference in thermal expansion, thermal strain, etc. is alleviated and eliminated by the metal coating layer 3. This is the structure that was created. FIG. 2 shows a preferred example of an apparatus for spatter deposition to obtain the sliding member according to the present invention. In this figure 2, 5 is a vacuum chamber, 6 is a silicon target, 7 is a permanent magnet,
8 is a heater, 9 is an alumina base with metallization, 10 is an auxiliary electrode, 1 1 and 12 are high frequency power supplies, 13 is a DC power supply, 14 is a main valve, 15 is an automatic pressure regulator, 16 is a pico ammeter, 17 is a mass spectrometer, 8 is an argon gas introduction valve, and 19 is an acetylene gas introduction valve.This sputtering apparatus may be called a magtron type sputtering apparatus in terms of form. To explain how to obtain the sliding part shown in FIG. 1, first, a metal coating layer 3 is provided on an alumina base 2, that is, an alumina base 9 that has been subjected to metallization is placed in a vacuum chamber. 5, the vacuum chamber 5 is evacuated to the order of 10-6 rr, the heater 8 is heated to within the range of 500 to 100,000, and the acetylene is evacuated from the valve 19 to 10-4 to 10
Argon is introduced up to -5 order, and then argon is introduced up to 10-3 order from valve 18. Next, power is applied to the silicon target 6 by the high frequency power source 1 or the DC power source 13 to start spatter deposition. In this way, a silicon carbide coating layer 4 is formed on the metal coating layer 3 of the alumina substrate 9 which has been subjected to metallization. Then, the sliding member 1 shown in FIG. 1 is completed. Incidentally, by using the sputtering apparatus shown in FIG. 2, the composition of silicon carbide in the silicon carbide coating layer 4 of the sliding member 1 can be conveniently and continuously changed. For example, it is possible to first deposit silicon carbide containing an excess of free silicon, and then gradually change the composition continuously to stoichiometric silicon carbide. In other words, in FIG.
The current value of this picoammeter 16 is made to correspond to the acetone partial pressure. Therefore picoammeter 16
If the output current is set arbitrarily, the automatic pressure regulator 15 will operate according to the output current, the valve attached to the automatic pressure regulator 15 will open and close, and the acetylene partial pressure will change from low pressure to high pressure. This is automatically controlled, and the silicon carbide coating layer 4 can be continuously and precisely controlled from silicon carbide containing excess silicon to silicon carbide having a normal stoichiometric composition.

With such a silicon carbide coating layer 4, free silicon and the metal of the metal coating layer 3 are easily bonded to each other, making it possible to obtain a sliding member 1 with further improved adhesion. Next, examples will be shown. As an example substrate, molybdenum (Mo) metallization was applied to one end surface of an alumina (A-203) substrate having an outer diameter of 30 feet, an inner diameter of 20 feet, and a thickness of 8 skins by a conventional method.

In order to form a silicon carbide coating on this metal coating layer made of molybdenum, the operating conditions for spatter deposition were as follows: high frequency power: 500W, acetylene partial pressure: 3×10-
As a result, a silicon carbide coating layer with a thickness of 11.5 m was obtained. The surface of the silicon carbide was a mirror surface, and the Vickers hardness value was 3100 kg/. Furthermore, the obtained sliding member was subjected to a dry abrasion test for 100 hours using a Suzuki type abrasion tester with carbon as the partner material, and the result was 1/1.
The amount of wear was measured using a surface measuring device capable of measuring up to 0,000 skin, and the amount of wear was zero. Then, in order to check the peel strength of the sliding member, both end surfaces of the sliding member were adhered to each other with epoxy resin having a tensile strength of 200 k9/base, and when a tensile test was performed, the sliding member broke at the epoxy resin portion. From this, it is thought that the peel strength of the coating layer is 200 kg/or more. As described above, in the emotional member according to the present invention, the alumina base and the silicon carbide coating layer are bonded together through the metal coating layer to have a strong peel strength of 200 k9/female or more, and at the same time have a Young's modulus of Since it is a structure in which only constituent materials with high efficiencies are integrated, it can withstand high loads (generally 2000 kg/c material/m/s or more), and a dense silicon carbide coating layer can be obtained by sputter deposition.

Furthermore, since inexpensive alumina is used as the base material and it can be easily manufactured, the sliding member can be immediately provided to the industrial market.

In addition, since this sliding member has extremely high wear resistance, it can be applied to the sealing rings of mechanical seals, sliding surfaces of bearings, sliding parts of turbines, pumps, etc., and other general parts. It can be effective.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view of a sliding member according to the present invention, and FIG. 2 is a schematic sectional view of a sputtering apparatus for manufacturing the sliding member of FIG. 1. DESCRIPTION OF SYMBOLS 1...Sliding member, 2...Alumina base, 3...Metal coating layer, 4...Silicon carbide coating layer. Figure 1 Figure 2

Claims (1)

[Claims] 1. A sliding member in which a metal coating layer is provided on the surface of an alumina substrate to be coated with silicon carbide by sputter deposition to form silicon carbide.