JP3205304B2 - Sliding member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal member such as a mechanical seal and a gas seal and a sliding member such as a bearing.

[0002]

2. Description of the Related Art As materials for forming seal members such as mechanical seals and gas seals and sliding members such as bearings,
Conventionally, carbon, silicon carbide, cemented carbide and the like have been widely used in combinations of carbon to silicon carbide, carbon to cemented carbide and the like.

[0003] In recent years, with the need for high speed, high pressure, and large size of fluid machinery, the use conditions of sliding members have become increasingly severe, and frictional heat accompanying sliding contact between solids is repeatedly generated. There is a problem of thermal shock destruction caused by cracking and cracking caused by thermal fatigue. In addition, high strength silicon carbide or cemented carbide molded products are used as seal members for rotating equipment at high speeds, high pressures, etc., but these are brittle and have bands such as bands to prevent damage due to increased centrifugal force. Requires reinforcement members.

Therefore, as a method of preventing breakage, the base material of the sliding member is formed of a non-brittle material such as a metal material, which is not high in strength, and the sliding surface is coated with a hard thin film. Methods for strengthening are being studied. However, in surface modification such as carbonization and nitriding, deformation due to heating during the treatment is large, and strength is reduced, such as peeling of the hard thin film from the base material due to strain. In ion implantation, the implantation depth is limited, and it is difficult to obtain a desired strength. A method of forming a hard thin film on a sliding surface by physical vapor deposition (PVD) or chemical vapor deposition (CVD) can sufficiently form a modified portion.
It is necessary to heat the sliding member (base material) to a certain degree. In the case of PVD, conventionally, in order to obtain a high-strength coating, the substrate temperature is heated to about 300 to 500 ° C., and also in this case, the strength is reduced due to deformation of the sliding member.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a sliding member having excellent wear resistance.

[0006]

According to a first aspect of the present invention, there is provided a sliding member, comprising:
%, Cr is 14 to 32 at%, and N is 14 to 36 at%, and a ternary amorphous wear-resistant material thin film is formed.

[0007] The sliding member according to the second aspect is characterized in that Ti is 44 to 60 at.
%, Cr is 0.4 to 5.0 at%, and N is 40 to 45 at%, and a ternary crystalline wear-resistant material thin film is formed.

By forming such a thin film on the sliding surface, a sliding member having excellent wear resistance can be obtained. In addition, such a wear-resistant material thin film, under vacuum,
Evaporate metal titanium (Ti) and metal chromium (Cr)
At the same time as ionizing the evaporant by arc discharge, it reacts with nitrogen gas (N ₂ ) and deposits on the sliding surface of the substrate.
It can be formed by a so-called arc discharge type ion plating method. According to such a method, it is possible to obtain a wear-resistant material thin film that satisfies the above-described desired conditions and has small distortion in the film.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an example of the configuration of an ion plating apparatus for forming a TiCrN thin film on a sliding surface of a base material. The substrate 2 is disposed and fixed to a holder 4 at the tip of the rotating shaft 3 so as to be coaxial with the rotating shaft 3. Holder 4
Is equipped with a temperature control device (not shown) to control the temperature of the base material. Evaporation source 5a (metallic titanium) facing the substrate 2
5b (metal chromium) is arranged, and emits titanium vapor from the evaporation source 5a and chromium vapor from the evaporation source 5b toward the base material 2. Titanium vapor particles and chromium vapor particles 6
Are ionized by the arc discharge generated by the ionization electrode 8. On the other hand, a nitrogen gas 9 is introduced between the evaporation sources 5a and 5b and the substrate 2, and a reaction product of the ionized titanium vapor particles and chromium vapor particles 10 reacting with the nitrogen gas is deposited on the substrate 2, and the sliding is performed. A TiCrN thin film is formed on the moving surface.

The physical properties of the formed TiCrN thin film include the temperature of the thin film forming surface of the base material, the bias voltage applied to the base material, the evaporation speed from the evaporation source, the flow rate (introduction speed) of nitrogen gas, and the evaporation method of the evaporation source. Although it relates to the working pressure, the ionization condition of the evaporant, etc., these are not particularly limited, and may be appropriately set according to the desired physical properties of the TiCrN thin film. Preferably, the substrate temperature on the thin film forming surface (sliding surface) is 100 ° C. or less, the bias voltage is 50 V or less, and the film forming speed is 4 ° / s or less. In addition, as shown in FIGS. 5, 6, and 11, which will be described later, the surface strain amount or friction coefficient in the horizontal direction of the thin film can be controlled by the flow rate of the nitrogen gas.

Next, the sliding member of the present invention in which the above-mentioned TiCrN thin film is formed on the sliding surface will be described. FIG. 2 is a cross-sectional view showing a configuration of a rotary ring of a gas seal which is an example of the sliding member of the present invention. Using martensitic stainless steel (SUS420J2) as the base material 2, processing it into a predetermined shape, then quenching
(980 ° C., 1 hour) and tempering (980 ° C., 4 hours), and the thin film-formed surface was lapping-finished so that the surface roughness became Ra = 0.05 μm or less.

After cleaning the sliding surface of the substrate 2 by ion bombardment (cleaning conditions: RF 0.6 kW, Ar flow rate 100 ml / min, bias voltage 1 kV, high frequency glow discharge for 15 minutes), the substrate 2 is set in the apparatus of FIG. Then, while rotating the substrate 2, various conditions (temperature of the thin film forming surface of the substrate, bias voltage applied to the substrate, flow rate of nitrogen gas (introduction speed), film forming speed, etc.) )
Then, a 3 μm-thick TiCrN thin film 20 was formed.

FIG. 3 shows the relationship between the temperature of the thin film forming surface of the base material (set temperature of the substrate) and the surface strain in the thin film horizontal direction on the sliding surface of the rotating ring (TiCrN thin film surface). FIG. 4 shows the relationship between the bias voltage value applied to the base material and the surface strain in the horizontal direction of the thin film at each temperature of the thin film forming surface of the base material.

[0014] The measurement of the amount of surface distortion is performed by a universal surface shape measuring instrument.
(SE-3FA manufactured by Kosaka Laboratory Co., Ltd.) from one end to the other end of the sliding surface of the rotating ring (outer end and inner end)
The amount of deformation was traced (magnification 5000 × 10) until the end, and the amount of change between both ends (inclination height) was defined as the amount of surface distortion (unit: μm).

From FIGS. 3 and 4, it can be seen that the temperature of the thin film forming surface of the base material and the bias voltage applied to the base material greatly influence the important surface strain in the horizontal direction of the thin film of the sliding member. It can be seen that it is indispensable to minimize the temperature of the thin film forming surface of the substrate and the bias voltage applied to the substrate to minimize the amount of distortion. Preferably, the substrate temperature on the sliding surface is 100 ° C. or less, the bias voltage is 50 V or less, and the film forming rate is 4 ° / s or less.

On the other hand, FIGS. 5 and 6 show the composition ratios of Ti, Cr, and N (contents of each element (at
%) And the sliding surface of the rotating ring (TiCr
9 shows the relationship with the surface strain in the horizontal direction of the thin film on the N thin film surface) for each nitrogen gas flow rate (introduction speed).
The composition ratio was calculated for each TiCrN thin film by performing X-ray elemental analysis using EPMA (X-ray microanalyzer manufactured by JEOL Ltd.). 5 and 6, there is no correlation between the composition ratio and the surface strain amount in the horizontal direction of the thin film. Even when a film having a desired composition is obtained, the surface strain amount is changed by a change in film forming conditions such as a flow rate of nitrogen gas. It turns out that it can be controlled.

Next, FIG. 7 shows the composition ratios of Ti, Cr, and N, which change with the change of the film forming conditions, and the sliding surface (Ti
This is a diagram showing the correlation with the crystallinity of the (CrN thin film surface), and the horizontal axis is [N content (at%)] / ｛[Ti content (at%)] +
[Cr content (at%)]｝, the vertical axis is [Cr content (at%)]
/ [Ti content (at%)]. The composition ratio of Ti, Cr and N was calculated from the measured value of X-ray elemental analysis by EPMA in the same manner as described above. Table 1 shows the value of the composition ratio of each example, and Table 2 shows the value of the composition ratio of the TiN thin film as a comparative example. FIG. 8 shows the correspondence between the plot of FIG. 7 and the example of Table 1 and the crystallinity area corresponding to FIG. 9 described below (circled numbers are examples in Table 1 and triangular numbers are Corresponding to the reference example in Table 1).

The crystallinity was measured using an X-ray diffractometer (X-Ray Diffractmeter RINT-2000, manufactured by Rigaku Corporation) under the following measurement conditions:
It was determined from the diffraction pattern obtained using a Cu-Kα ray (50 kV × 250 mA). FIG. 9 shows a representative X-ray diffraction pattern corresponding to the correlation between the composition ratio of Ti, Cr, and N and the crystallinity. 8A shows an amorphous film (corresponding to area A in FIG. 8), FIG. 8B shows an amorphized film (corresponding to area B in FIG. 8), and FIG. In the X-ray diffraction pattern of the amorphous film (corresponding to area C in FIG. 8), the amorphous film has two peaks indicated by ○ (●).
Indicates a peak of the substrate), and a clear peak is not observed. In a crystalline film, two peaks appear clearly. Table 3 shows the correlation between the ranges of the contents (at%) of Ti, Cr, and N and the crystallinity determined from the results of the X-ray elemental analysis and the X-ray diffraction pattern.

Further, from FIG. 7 to FIG. 9, the condition that the amorphous film and the crystalline film appear in the TiCrN thin film is expressed by the following equation (1).
Or, it can be seen that this is the case where the relationship of (2) is satisfied. Range where an amorphous film appears: y ≧ 1.1x−0.18 (1) Range where a crystalline film appears: y ≦ 0.3x−0.04 (2) where x = [N Content (at%)] / ｛[Ti content (at
%)] + [Cr content (at%)]｝, y = [Cr content (at
%)] / [Ti content (at%)]. Note that y = 1.1x−0.18 (1 ′) is shown by a solid line in FIGS. 7 and 8, and y = 0.3x−0.04 (2 ′) is shown in FIG. 8 are indicated by dotted lines.

On the other hand, a thrust type friction and wear tester (EFM-III-E manufactured by Toyo Baldwin Co., Ltd.) was applied to each of the rotating rings of Examples, Reference Examples and Comparative Examples, and the mating material was changed to the sliding surface. Is a fixed ring made of a ring-shaped carbon molded body having a specified surface roughness (Carbon P9867 for high-load mechanical seal manufactured by Pure Carbon Co.), and the surface pressure applied to the sliding surface of the fixed ring in the air at room temperature is 5 kgf / cm ^2. The thrust load was adjusted so that the peripheral speed (slip speed) was 2 m / s and the traveling distance was 7200 m, and the amount of carbon wear on the stationary ring, the amount of TiCrN thin film on the rotating ring,
The coefficient of friction was measured. The amount of wear is measured from the height of the rotating ring and the stationary ring (1/1000 micrometers) and the state of the surface trace. The friction coefficient is calculated from the friction torque detected by the load cell. The results are shown in Tables 1 and 2.

FIG. 10 shows the dry sliding property of each TiCrN thin film plotted in a graph in which the horizontal axis represents the composition ratio represented by x and the vertical axis represents the composition ratio represented by y. The evaluation results are shown in FIG. 11, and the relationship between the composition ratio of each TiCrN thin film and the coefficient of friction is shown for each nitrogen gas flow rate in a graph in which the horizontal axis represents the composition ratio represented by x.

From the results shown in FIGS.
It can be seen that the TiCrN thin film has a low friction coefficient and shows good wear resistance in either the amorphous film or the crystalline film.

Therefore, in the TiCrN thin film, from Table 3, Ti is 45 to 60 at%, Cr is 14 to 32 at%, and N is 1 to 32 at%.
Containing 4 to 36 at%, or 44 to 60 at% of Ti,
The composition contains 0.4 to 5.0 at% of Cr and 40 to 45 at% of N, and the composition ratio of Ti, Cr and N is amorphous or crystalline in the above formula (1) or (2). It can be seen that good abrasion resistance is exhibited when the relationship is satisfied.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

In the above embodiment, a cut product of stainless steel was used as the base material. However, the present invention is not limited to this. Materials and materials such as ceramics can be appropriately selected, and the processing method can also be selected according to the material and shape of the base material.

Further, in the above embodiment, the rotary ring of the gas seal is used as the sliding member. However, the present invention is not limited to this. The sliding member has a sliding surface, and the sliding surface is made of the wear-resistant material of the present invention. Any member can be used as long as the member can be formed by the above. For example, the sliding surface of the stationary ring of the gas seal may be formed of the wear-resistant material of the present invention, or the sliding surface of the movable member or the stationary member of the mechanical seal or the bearing may be formed of the wear-resistant material of the present invention. It may be formed. Further, the sliding surface of the slide plate that slides opposite to the slide bearing of the bearing device as shown in FIG. 12 may be made of the wear-resistant material of the present invention (in FIG. 12, reference numeral 22 denotes a sole plate, 23 is a slide plate, 24 is a piston, 25 is a shim, 26 is a bearing, 27 is a seal ring, 28 is an elastomer, and 29 is a baespot).

Further, in the above embodiment, carbon was used as the material for forming the sliding surface of the mating member to be combined with the sliding member of the present invention. A material used as a surface forming material can be used. Further, the sliding member of the present invention,
It can be suitably used for turbines, blowers, compressors, stirrers and the like.

[0030]

The sliding member of the present invention has a Ti content of 45 to 60 at.
% Ternary amorphous wear-resistant material thin film containing 14 to 32 at% of Cr and 14 to 36 at% of N, or 44 to 32 at% of Ti.
A ternary crystalline wear-resistant material thin film containing 60 at%, Cr at 0.4 to 5.0 at%, and N at 40 to 45 at% is formed. Each thin film has a small coefficient of friction. Since the distortion in the material is small and the wear resistance is remarkably improved, the durability during sliding is excellent.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of the configuration of an ion plating apparatus for forming a TiCrN thin film according to the present invention.

FIG. 2 is a sectional view showing a rotating ring of a gas seal which is an example of the sliding member of the present invention.

3 is a graph showing a relationship between a temperature (set temperature) of a thin film forming surface of a substrate and a surface strain amount in a horizontal direction of the thin film in the rotating ring of FIG. 2 for each bias voltage value applied to the substrate.

4 is a graph showing a relationship between a bias voltage value applied to a substrate and a surface strain in a horizontal direction of a thin film in the rotating ring of FIG. 2 for each temperature of a thin film forming surface of the substrate.

FIG. 5 shows Ti and Cr in a thin film formed on the rotating ring of FIG. 2;
Composition ratio ([Cr content (at%)] / [Ti content (at
%)]) And a graph showing the relationship between the surface strain amount in the horizontal direction of the thin film and the flow rate (introduction speed) of the nitrogen gas.

FIG. 6 shows Ti and C in a thin film formed on the rotating ring of FIG.
r, composition ratio of N ([N content (at%)] / {[Ti content (at%)] + [Cr content (at%)]}) and surface distortion in the horizontal plane direction of the thin film 4 is a graph showing the relationship with the amount for each nitrogen gas flow rate (introduction rate).

7 is a diagram showing the correlation between the composition ratio of Ti, Cr, and N, which changes with the change in the film forming conditions of the thin film formed on the rotating ring of FIG. 2, and the crystallinity.

8 is a diagram showing the correlation between the composition ratio of Ti, Cr, and N and the crystallinity in FIG. 7 and the corresponding relationship between Examples and Reference Examples.

9A is a typical X-ray diffraction pattern of a TiCrN amorphous film, and FIG. 9B is a typical X-ray diffraction pattern of a TiCrN amorphous film; FIG. FIG. 4 is a view showing a typical X-ray diffraction pattern of a TiCrN crystalline film.

FIG. 10 shows Ti and Ti in the thin film formed on the rotating ring of FIG.
4 is a graph showing the correlation between the composition ratio of Cr and N and dry sliding properties.

FIG. 11 shows Ti and Ti in the thin film formed on the rotating ring of FIG.
5 is a graph showing the relationship between the composition ratio of Cr and N and the coefficient of friction.

FIG. 12 is a main part configuration diagram of a bearing device to which a slide plate as an example of the sliding member of the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arc discharge type ion plating apparatus 2 Substrate 3 Rotation axis 4 Holder 5a Evaporation source (metal titanium) 5b Evaporation source (metal chromium) 6 Vapor particles (Ti, Cr) 7 Filament 8 Ionization electrode 9 Reaction gas (N2) 10 Ionized vapor particles (Ti, Cr) 11 DC power supply 12 Power supply 13 EB gun 14 Roughing valve 15 Main valve 16 Cryopump 17 Oil rotary pump 20 TiCrN thin film 21 Sliding surface

Continuation of the front page (56) References JP-A-4-297568 (JP, A) JP-A-7-243047 (JP, A) JP-A-7-173608 (JP, A) JP-A-6-330348 (JP) , A) JP-A-6-330347 (JP, A) JP-T-58-500172 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23C 14/00-14/58 C23C 16/34 F16C 33/12 C01G 37/00 CA (STN)

Claims (2)

(57) [Claims] 1. Ti is 45 to 60 at% and Cr is 14 to 3%.
A sliding member comprising a ternary amorphous wear-resistant material thin film containing 2 at% and 14 to 36 at% of N. 2. Ti content of 44-60 at% and Cr content of 0.4-at.
A sliding member comprising a ternary crystalline wear-resistant material thin film containing 5.0 at% and N of 40 to 45 at%.