JPS63231929A - Ceramic coating metal - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Objective of the Invention 1 (Industrial Application Field) The present invention relates to a ceramic coating metal with improved wear resistance and adhesion of the ceramic coating layer, and is particularly applicable to rotating elements such as refrigerant compressors. It concerns the ceramic coating metal used.

(Prior Art) In order to improve the reliability of electrical devices and components, attempts have been made to apply ceramic coatings to the surfaces of metal substrates that constitute electrical devices and components. The above ceramic coating technology will be explained using a refrigerant compressor as an example. FIGS. 5 and 6 show schematic diagrams of a hermetic refrigerant compressor. FIG. 5 is a longitudinal cross-sectional view of the hermetic refrigerant compressor, and FIG. 6 is a cross-sectional view showing the compression mechanism of the compressor.

That is, the main rotating shaft 3 of the motor section 1 is integrally provided with a crankshaft 4 and a sub rotating shaft 5, and the main rotating shaft 3 is connected to the main bearing 1.
1, and the sub rotating shaft 5 is attached to a sub bearing 12. A rotating body 7 is attached to the crankshaft 4, and this rotating body 7 is eccentrically attached to the cylinder 6 of the compression mechanism section 2. A groove 8 is formed in the cylinder 6, and a blade 9 that reciprocates due to the planetary motion of the rotating body 7 is inserted through the groove 8.
The rotor 7 is pressed against the rotating body 7 by the rotation member 7. A low pressure chamber 13 and a high pressure chamber 14 are formed in the cylinder 6 by the rotating body 7 and the blades 9, and the cylinder 6 is provided with an absorption gas inlet 15 and a compressed gas outlet.

The active parts that make up the compression mechanism of this type of refrigerant compressor are mainly made of cast iron or sintered metal, and lubricating oil is constantly supplied to these sliding surfaces to prevent seizure and abnormal wear. is prevented.

However, during overload operation or high speed rotation, the following wear is expected.

(1) Since the center of gravity of the crankshaft 4 and the rotating body 7 is offset from the center of rotation, the centrifugal force of the crankshaft 4 and the rotating body 7 itself causes the main rotating shaft 3 to move toward the main bearing during excessive load operation or high-speed operation. At 11, the sub-rotating shaft 5 is also pressed against the sub-bearing 12, causing breakage of the lubricating oil film, increasing the chance of metal-to-metal contact, and causing wear.

(2) Since the blade 9 is pressed against the rotating body 7 under high pressure, wear occurs between the tip of the blade 9 and the outer peripheral surface of the rotating body 7. In order to prevent this wear, Japanese Patent Application Laid-Open No. 55-5
Studies have been made to improve the wear resistance by using ceramic coatings as shown in Japanese Patent Application Laid-open No. 591, Japanese Patent Application Laid-Open No. 57-32096, and Japanese Patent Application Laid-Open No. 58-77192. There are many types of ceramic coatings made by chemical vapor deposition, physical vapor deposition, thermal spraying, etc., but in any of these methods, the adhesion between the coating layer and the base material, which controls wear resistance, is Nothing was considered beyond the structure. In fact, when a refrigerant compressor is assembled using a shaft with a ceramic coating layer on carbon steel using each of the above methods and operated under high load and high speed, the ceramic coating 1 peels off and easily causes wear. There was a drawback that

This problem occurs not only in the pressure lame mechanism of a refrigerant compressor, but also in sliding parts of various machines when ceramic coating is applied.

(Problems to be Solved by the Invention) The present invention has been made in consideration of the fact that in the above-mentioned conventional technology, the adhesion between the ceramic coating layer and the metal base material is poor and wear occurs. It is an object of the present invention to provide a ceramic coated metal that has excellent abrasion resistance and has excellent adhesion between a ceramic coating layer and a metal base material.

[Structure of the Invention J <Means and Effects for Solving the Problems] In order to achieve the above objects, the present invention provides an amorphous structure film formed on a metal base material, and a film with an amorphous structure formed on a metal base material. It is characterized by comprising dense fine-grain polycrystals or m-female polycrystals @ film formed by laminating on the film, and the substrate temperature,
By changing the raw material gas supply amount and degree of vacuum, I!
l! A plurality of ceramic coating layers created by I-Seizo are continuously provided to improve the adhesion between the ceramic coating layer and the metal base material while having good wear resistance.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIGS. 1(a) and 1(b) show ceramic coating gold #117 according to the present invention, and FIG. 1(C) shows conventional comparative amount 22.

In FIGS. 1(a), (b), and (C), the base material 20 is generally made of a metal material such as carbon steel or stainless steel, and the structure of the coating layer is as follows.

■As shown in FIG. 1(a), the ceramic coating layer has a two-layer structure: an amorphous structure film 19 with a thickness of 5 μm or less is provided on the base material 20, and then a dense film 19 with a film thickness of 20 μm or less is provided on the base material 20. This can be obtained by providing a fine-grained polycrystalline or fibrous polycrystalline structure WA18.

At this time, fine grain polycrystalline or s-fiber polycrystalline structure 118
The particle size is 1.0 μm or less, and the ratio of height to particle size is 1.0 or more.

■As shown in Figure 1(b), the ceramic coating layer consisting of three layers has a film 21 made of ceramic fine particles with a particle size of 2.0 μm or less on top of the ceramic coating layer (2) with a thickness of 10 μm or less. It can be obtained by laminating them.

(2) As shown in FIG. 1C, in the conventional comparative amount 22, only the amorphous structure film 19 is provided on the base material 20.

The thickness of these ceramic layers may be changed as appropriate depending on the application, but is preferably 10 μm or less. Moreover, a plurality of film structures of three or more layers may be used.

The ceramic coated metal of the present invention thus formed has the following characteristics.

■By forming an amorphous layer without grain boundaries in the bottom layer in contact with the metal base material, when the ceramic coating metal is exposed to high temperatures, the ceramic layer has a smaller coefficient of thermal expansion than the metal base material. This amorphous layer prevents cracks caused by grain boundaries.Also, even when the ceramic coating metal is subjected to large pressure from the outside, this amorphous layer can prevent cracks caused by grain boundaries. can. As explained above, the presence of this amorphous layer improves the adhesion of the ceramic layer to heat and pressure.

■ If the second layer located on top of the amorphous layer is dense fine-grained polycrystalline or 41! If the ceramic coating metal is subjected to a large external pressure, the IfI-like polycrystalline layer absorbs the pressure by slightly shifting the fine crystal grains that form this layer, and prevents peeling that occurs when the ceramic layer cracks. This improves the adhesion of the ceramic layer to the metal substrate.

■The layer consisting of fine particles located at the top is such that when the ceramic coating metal slides, the fine particles move due to external pressure, reducing surface roughness and improving conformability. WJ sliding action is obtained and wear resistance is improved.

The above characteristics enable ceramic coating to be applied to soft metal substrates, expanding the range of applications of ceramic coatings.

Chemical vapor deposition (CVD), physical vapor deposition (PVD), thermal spraying, etc. can be applied to the method for forming the ceramic layer having the above structure.

Among these methods, the CVD method and the P.sub.2/D method are preferred because they provide high dimensional accuracy through low-temperature processing.

In particular, the plasma CVD method can be used in a wide range of applications because it can use a wide variety of reaction gases.

When using the CVD method or the PVD method, reaction conditions are appropriately changed depending on the base material, ceramic material, and purpose of use. The ceramic layer may be made of wear-resistant materials such as silicon nitride, titanium nitride, aluminum nitride, boron nitride, silicon carbide, titanium carbide, and aluminum carbide.

Further, as the component constituting the ceramic layer, a single component or a plurality of components of the above ceramic materials may be used.

The present invention will be explained below based on specific examples.

An example in which the ceramic coated metal of the present invention is applied to the shaft of a compressor will be described.

First, a shaft cut from gray cast iron to a predetermined size is degreased with isopropyl alcohol, and then inserted into a capacitively coupled plasma CVD device made of a stainless steel container.
set on the board. Next, the inside of the equipment was pumped to 10' Torr using a mechanical booster pump and a rotary pump.
Exhausted to a certain extent. Thereafter, in order to degas the gas adsorbed on the inner wall and shaft of the apparatus, the chamber was further evacuated to 10@-8 Torr using an oil diffusion pump or a cryopump, and the substrate was heated to a temperature of 300.degree. Subsequently, the exhaust system was switched to a mechanical booster pump and a rotary pump, and the internal pressure was brought to about 1 TOrr while introducing Ar gas at a flow rate of 100,080 CM.

Next, 1 KW of 13.56 MHz high frequency power was applied to generate plasma, and sputter etching was performed on the shaft for 1 hour. Next, gas was introduced so that the gas flow rate of SiH4 and N2 was 1:16, and 400 W of high frequency power was applied to generate plasma, and the substrate temperature was raised to 2.
A film thickness of 2 μm was achieved by forming a film at 00 to 250°C for 15 minutes, 250 to 300°C for 40 minutes, and 300 to 350°C for 5 minutes.
A silicon nitride layer of m was deposited. On the other hand, for comparison, a silicon nitride film having a thickness of 2 μm was formed in 1 hour while keeping the substrate temperature constant at 250° C.

As a result of examining the film structure of the silicon nitride layer for the above two types of shafts using a scanning electron microscope, it was found that in the shaft of the example, the amorphous film was 0.4 μm1, and the dense 4I fibrous polycrystalline structure film was 1.4 μm1. Figure 1 shows a fine particle film of 0.2 μm (
The three-layer structure of b) was confirmed.

On the other hand, in the comparative example, only an amorphous It4 film was formed as shown in FIG. 1(C).

Auger electron spectroscopy (AES) was performed on the ceramic coating layers of the two types of shafts that were blued in this way.
Figure 2 shows the results of examining the depth distribution of each element. As a result, the g of the ceramic coating layer! 4
It was confirmed that the elemental distribution in the depth direction was the same even though the 11 structures were different.

Next, in order to examine the adhesion of the silicon nitride layer on the two types of shafts obtained, a scratch test was conducted, and the results are shown in FIG. 3. Shaft 23 of the embodiment of the present invention Compared with the conventional comparison amount 24, the rise of the AE (acoustic emission) signal was significantly shifted to the high load side, and it was recognized that the adhesion was improved.

In addition, in order to investigate the wear resistance and adhesion of the nitrogen (t) silicon layer for the two types of shafts, the torque-load correlation was evaluated using a wear tester. The results are shown in Fig. 4. Examples of the present invention It has been confirmed that the shaft 25 has lower torque in the entire load range than the conventional comparative shaft 26, does not cause seizure due to film peeling, has good friction characteristics and adhesion, and has wear resistance. Ta.

Furthermore, as a result of assembling a refrigerant compressor using the shaft of this embodiment of the present invention and conducting an actual machine test, i o o
Good wear resistance was obtained even with o o rpi.

Note that the present invention is not limited to members constituting a refrigerant compressor;
It can be similarly applied to a wide range of mechanical parts, cutting tools, etc. used in the sliding parts of each 1a device.

[Effects of the Invention] As explained above, the ceramic coated metal of the present invention has good wear resistance and excellent adhesion to the base material, so it can be used at high rotation speeds of equipment such as refrigerant compressors. It has the effect of increasing reliability and achieving higher loads.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the present invention and a conventional example, Fig. 2 is an element distribution diagram in the depth direction of an embodiment of the present invention and a conventional example;
Fig. 3 is a curve diagram showing the correlation between AE signal and load in the scratch test of the embodiment of the present invention and the conventional example, and Fig. 4 is a curve diagram showing the correlation between torque and load in the wear test of the embodiment of the invention and the conventional example. , FIG. 5 is a longitudinal sectional view showing an example of a refrigerant compressor, and FIG. 6 is a sectional view showing an example of the compressor mechanism section of FIG. 5. 17... Ceramic coated metal according to the present invention,
18... Dense fine grain polycrystalline or 4I fibrous polycrystalline structure film, 19... Amorphous film, 20... Base material, 21...
・Made of ceramic fine particles! I. Applicant's agent Patent attorney Takehiko Suzue (Figure 1) Figure 2 (N) Figure 3 Figure 4

Claims (2)

[Claims] (1) Comprising an amorphous structure film formed on a metal base material and a dense fine-grain polycrystalline or fibrous polycrystalline structure film formed by laminating on this amorphous structure film. Features Ceramic Coated Metal (2) As the dense fine-grained polycrystalline or fibrous polycrystalline structure film, a dense fibrous polycrystalline structure film in which a film made of fine particles is laminated on the surface is used. ceramic coating metal