JP3339994B2 - Wear-resistant material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a titanium alloy coated with a hard carbon film which is excellent as a wear-resistant member or a sliding member.

[0002]

2. Description of the Related Art Diamond is excellent in hardness, wear resistance, solid lubricating property, heat conductivity, etc., so that various members such as sliding members, cutting tools, abrasives, and wear-resistant mechanical parts are used. It is being used for. Further, in recent years, it has become possible to synthesize a hard carbon film such as a diamond film by a vapor phase growth method under a low pressure, so that the demand for the above-mentioned applications is further increasing.

[0003]

However, the hard carbon film-coated member produced by the vapor phase growth method has characteristics such as high hardness and low coefficient of friction, but the adhesion strength between the substrate material and the film. Is insufficient, the film is peeled off, and the hard carbon film has not yet exhibited excellent properties such as high hardness and low friction coefficient as a sliding member or a wear-resistant member.

There are several reasons why the adhesion strength between the substrate and the hard carbon film is low.

(1) Hard carbon such as diamond and diamond-like carbon has poor wettability with other substances.

(2) Residual stress is generated due to a difference in thermal expansion coefficient between the hard carbon film and the substrate.

(3) In the case of a substrate containing a metal element such as Fe, Co, or Ni in which carbon is easily diffused into the substrate, such as a cemented carbide, graphite is likely to be preferentially formed on these metal elements. .

As a solution to the above (3), for example, the surface of a cemented carbide is etched with an acid solution to remove metal elements such as Fe and Co in a binding phase described in JP-A-1-201475. There is a way to do that. However, in this method, there is a problem that the hard phase is easily dropped due to the removal of the binder phase, the strength of the base is reduced, and the hard carbon film is peeled off together with the base.

As a solution to the above (2), for example, Japanese Unexamined Patent Publication (Kokai) No. 61-291493 discloses a ceramic sintered body mainly composed of silicon nitride or silicon carbide having a thermal expansion coefficient close to that of diamond. Are described. According to this method, the problem of the coefficient of thermal expansion described in (2) can be solved, but at present, the adhesion strength is insufficient for the reason of (1). Also,
Jigs and tools such as wear-resistant members, sliding members, and cutting tools are used in harsh environments, and therefore require high strength and high toughness. For example, when a ceramic sintered body such as silicon nitride is used as a base, the toughness is a disadvantage.

An object of the present invention is to solve the above-mentioned problems and to provide a hard carbon film-coated wear-resistant member having excellent adhesion strength of a hard carbon film and excellent fracture resistance.

[0011]

As a result of repeated studies on the above object, the present inventor has found that titanium or a titanium alloy mainly containing titanium is used as a substrate, and that the surface of the substrate contains at least diamond and silicon carbide. The hard carbon film is coated with an intermediate layer having a surface roughness (Rmax) of 2 μm or less, and a film having a peak at 1160 ± 40 cm ⁻¹ in Raman spectroscopic analysis is formed. It has been found that as a wearable member, excellent adhesion and wear resistance are achieved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A wear-resistant member according to the present invention comprises a substrate 1, an intermediate layer 2, and a hard carbon film 3, as shown in FIG. As described above, the base 1 is required to have high strength and high toughness and adhesion to the hard carbon film from the usage environment. Although a cemented carbide is suitable as a high-strength, high-toughness material, it is quite difficult to improve the adhesion to a hard carbon film as described above. Therefore, according to the present invention, it is important to use titanium or a titanium alloy as a material having high strength and high toughness. Titanium is used in aircraft structural materials and medical materials, and is known to have the highest specific strength among metallic materials.

The titanium or titanium alloy used in the present invention includes titanium metal or titanium and A
It is an alloy with 1, V, Mo, Zr, Sn, Cr, Mn, and Fe, and desirably contains 70% by weight or more of titanium. More desirably, an alloy containing titanium as a main component and containing at least 2 to 8% by weight of Al is desirable.

Further, according to the present invention, in order to obtain an adhesion strength enough to be used as a wear-resistant member, FIG.
It is important to provide an intermediate layer 2 containing at least diamond 4 and silicon carbide 5 between the hard carbon film 3 and the base 1 as shown in FIG.

The reason why the formation of such an intermediate layer improves the adhesion strength between the hard carbon film and the substrate is considered as follows. Atoms are bonded by intervening electrons, but in general, electrons are shared by both atoms rather than ionic bonds, in which electrons between atoms are present on one side and bonded by electrical connection. An existing covalent bond has a stronger binding force. Diamond has a strong bonding force because it is constituted by a covalent bond of carbon.

Therefore, in order to improve the adhesion strength between diamond and a different compound, it is considered that a compound having a covalent bond having a similar bonding mode is desirable. Also, it seems that a compound containing carbon which is a component of diamond has better consistency. There are many carbon compounds, most of which are mainly ionic bonds. ADVANTAGE OF THE INVENTION According to this invention, the adhesion strength of a hard carbon film and a base | substrate improves by forming the layer in which silicon carbide and a diamond which are covalent bond compounds are mixed between a hard carbon film and a base | substrate.

Further, in the intermediate layer, the diamond 4
The metal carbide 5 and the metal carbide 5 do not exist separately in layers, but as shown in FIG. 1, a structure in which the metal carbide 5 surrounds the diamond 4, that is, the diamond is distributed in an island shape. Thus, a so-called anchor effect can be expected, and it is considered that the adhesion strength between the hard carbon film 3 and the base 1 is improved. The intermediate layer 2 has a thickness of 0.1 to 10
It is desirable that the film be formed with a thickness of μm, particularly 0.5 to 5 μm. The total thickness of the hard carbon film 3 and the intermediate layer 2 is preferably 1 to 100 μm, particularly preferably 2 to 20 μm.

The wear-resistant member of the present invention is obtained by coating a surface of a substrate made of titanium or a titanium alloy with a hard carbon film.
It is important to control the thickness to less than μm. This is because the surface roughness of the hard carbon film on the contact surface with the friction partner greatly affects the wear resistance and slidability. Therefore,
If the surface roughness of the hard carbon film exceeds 2 μm, the mating material is scraped or damaged by the hard carbon film. It is particularly desirable that the surface roughness of the film is 1 μm or less.

The surface roughness of a hard carbon film is greatly affected by the crystallinity of the film. When the hard carbon film has high crystallinity and is composed mainly of diamond, the surface roughness of the film also increases because the crystal grain size of the film tends to increase. On the other hand, the surface roughness of the hard carbon film can be controlled to be small by lowering the crystallinity of the hard carbon film and allowing microcrystalline diamond to be present. In addition, from the viewpoint of wear resistance, the inclusion of microcrystalline diamond is more excellent in wear resistance.

The presence of such microcrystalline diamond can be confirmed as a peak at 1160 ± 40 cm ⁻¹ in Raman spectroscopy. Therefore, the greater the peak intensity, the more microcrystalline diamonds are present,
The surface roughness of the film also tends to be small. With such a film configuration, the polishing step of the hard carbon film can be shortened, and the productivity is further improved. The peak intensity I ₂ of this microcrystalline diamond is 133 which is the peak of the main crystal of the diamond in Raman spectroscopy.
The intensity ratio (I ₂₎ to the peak intensity I ₁ of 3 ± 10 cm ⁻¹
/ I ₁ ) is desirably 0.02 or more, especially 0.15 or more.

As a method for producing the wear-resistant member of the present invention, in a vapor phase growth method, hydrogen, a carbon-containing gas, and a silicon-containing gas are introduced as raw material gases into a reaction chamber in which a substrate is provided, and are excited. Thus, an intermediate layer in which diamond and silicon carbide are mixed can be formed, and if the supply of the silicon-containing gas is stopped, a hard carbon film can be formed. As described above, the hard carbon film-coated abrasion-resistant member of the present invention can be synthesized only by controlling the supply amount of each gas type, so that a member excellent in productivity as before can be provided.

Examples of the carbon-containing gas used in forming the film include alkanes such as methane, ethane and propane, alkenes such as ethylene and propylene, alkynes such as acetylene, aromatic hydrocarbons such as benzene, and cyclopropane. And cycloolefins such as cyclopentene.

Oxygen-containing carbon compounds such as carbon monoxide, carbon dioxide, methyl alcohol, ethyl alcohol and acetone, and nitrogen-containing carbon compounds such as mono (di, tri) methylamine and mono (di, tri) ethylamine are also carbon. Can be used as source gas. These can be used alone or in combination of two or more.

Examples of the silicon-containing gas include halides such as silicon tetrafluoride, silicon tetrachloride, and silicon tetrabromide;
In addition to oxides such as silicon dioxide, silane compounds such as mono (di, tri, tetra, penta) silane and mono (di, tri, tetra) methylsilane, and silanol compounds such as trimethylsilanol can be given. These can be used alone or in combination of two or more.

Further, by introducing an oxygen-containing gas in addition to hydrogen, argon and helium gas as a carrier gas into the above-mentioned raw material gas for forming the hard carbon film, the film quality is improved and the film forming rate is increased. Can be. As the oxygen-containing gas used, O ₂ , CO, CO ₂ , NO, NO ₂ ,
Compounds composed of 2 to 4 atoms such as H ₂ O and H ₂ O ₂ , alcohols such as methyl alcohol and ethyl alcohol, ethers such as ethyl ether, ketones such as acetone, and aldehydes such as acetaldehyde And organic oxygen-containing compounds such as acids such as acetic acid, or acid esters, and glycols such as ethylene glycol.

These raw material gases are introduced into the reaction chamber at 1 × 10 ^-3 to
Introduced at a pressure of 100 torr, a microwave or high frequency was applied to generate plasma, and 200 to 10
By exposing the substrate heated to 00 ° C., an intermediate layer in which silicon carbide and diamond are mixed or a hard carbon film can be formed on the substrate surface. Furthermore, magnetic resonance (ECR) plasma can be generated by applying a magnetic field.

Further, as described above, it is necessary to adjust the surface roughness (Rmax) of the hard carbon film to 2 μm or less, but the surface roughness is determined by polishing the generated hard carbon film. As is clear from the examples described later, the hard carbon film containing microcrystalline diamond is obtained by increasing the concentration of the carbon-containing gas in the film forming process and reducing the proportion of oxygen in the source gas, as is clear from the examples described later. Can be formed. In this case, since the surface roughness after film formation is small, it is not necessary to polish the hard carbon film, or even if necessary, it can be adjusted in a short time.

The wear-resistant member of the present invention includes various types of sliding members such as cutting tools, jigs for metal working, drawing dies, slider members, cutting tools, abrasives, and wear-resistant mechanical parts. Can be used as

[0029]

According to the present invention, by adopting a titanium alloy for the substrate, it is possible to increase the toughness of the substrate, thereby preventing chipping of the substrate under severe use conditions and improving the adhesion to the substrate. Can be. In particular, by disposing a layer containing at least diamond and silicon carbide between the hard carbon film and the titanium alloy substrate, the peeling of the hard carbon film can be further suppressed.

Further, by reducing the surface roughness of the hard carbon film formed on the surface of the titanium alloy substrate, it is possible to improve the wear resistance of the wear-resistant member and to prevent damage to the wear-receiving member. it can. In particular, by including microcrystalline diamond in the hard carbon film to lower crystallinity, the surface roughness of the hard carbon film can be reduced. As a result, the film polishing process can be shortened, and excellent abrasion resistance in contact with a counterpart material,
It can show sliding characteristics.

[0031]

【Example】

Example 1 A raw material gas was introduced into a reaction furnace, and the pressure in the reaction chamber was set to 0.1.
The torr and the substrate temperature were set to 800 ° C. Table 1 shows the types and flow rates of the source gases. A magnetic field having a maximum intensity of 2 kGauss is applied by an ECR plasma CVD method, and under a condition of a microwave output of 3.0 KW, a Ti-6% Al-4% V alloy (alloy ratio is hereinafter referred to as "weight%") is applied to a substrate. A film was formed (Sample No. 1). Table 1 shows changes in the flow rate and pressure of the source gas during the film formation with the elapse of the film formation time. The sample N
FIG. 2 shows the results of Raman spectroscopic analysis for o.1.

[0032]

[Table 1]

The substrate was made of Ti-8% Al-1% V-1
% Mo alloy, Ti-10% V-2% Fe-3% Al alloy, Ti100%, Ti-15% Mo-5% Zr-3%
Coating was performed in the same manner in place of Al (Sample Nos. 2, 3, 4, and 5). Each of the prepared samples was subjected to a polishing step for 20 minutes.

Further, as a comparative example, a comparative sample (sample Nos. 6, 7, and 8) was prepared in the same manner as described above except that Si (CH ₃ ) ₄ was not supplied from the source gas compositions shown in Table 1 above. Produced.

With respect to the obtained film, a detection phase was identified by X-ray diffraction measurement, and the results are shown in Table 3. Further, the spectrum was measured by Raman microspectroscopy, and 1333 ± 10c
peak intensity I ₁ of the m ^-1, 1160 intensity ratio of the peak intensity I ₂ of ± 40 cm ^-1 to (I ₁ / I ₂₎ are shown in Table 3. Further, the surface roughness (Rmax) was measured by a stylus type surface roughness meter.

The sliding resistance (wear amount and friction coefficient of pins) of these members was evaluated by a pin-on-disk method. The conditions of the sliding test were room temperature, air,
Without lubrication, load 39.2N, sliding speed 2m / sec
c, 24 hours. The pins used were made of aluminum. The wear amount of the aluminum pin was evaluated based on the weight change of the aluminum pin before and after the test. Table 3 shows the pin wear and the coefficient of friction.

Further, using a Vickers hardness tester, a load was applied to the film to lift the film from the surface of the substrate, and the adhesion between the film and the substrate was evaluated. Table 3 shows the results of measuring the load (critical load) at which peeling of the film began to occur.

Example 2 Next, Ti-6% Al-4% V, Ti-8%
Table 2 shows the raw material gas using an Al-1% V-1% Mo alloy.
A hard carbon film having good crystallinity was formed in exactly the same manner as in Example 1 except that the adjustment was performed as shown in Fig. 9. For Sample No. 9, a polishing process was performed for 20 minutes.
Was carried out for 40 hours.

For reference, a hard carbon film was formed under the conditions shown in Table 1 using a cemented carbide as a substrate, and the same evaluation as described above was performed (Sample No. 12).

[0040]

[Table 2]

With respect to the obtained hard carbon film-coated member, the identification of the crystal phase by Raman spectroscopy, the peak intensity ratio, the surface roughness, the sliding characteristics, and the critical load were measured in the same manner as in Example 1. 3 is shown.

[0042]

[Table 3]

In the results of Table 3, the samples No. 6, 7, 8
Shows that no intermediate layer was formed between the diamond and the carbide. In the abrasion test, the film was peeled off within 5 minutes after the start of the test, so the test was stopped halfway. Since the peeling of the film easily occurred, it can be seen that the adhesion strength between the film and the substrate was not sufficient as a wear-resistant member.
Also, the critical load is an extremely low value as compared with the sample of the present invention.

In sample No. 9, a diamond film having good crystallinity was formed via an intermediate layer. However, since the surface roughness exceeded 2 μm, the wear resistance was insufficient, and Was very early and the test was stopped 30 minutes after the start of the test.

All of the samples other than those described above did not peel off in the sliding test, and exhibited excellent sliding properties with a pin abrasion of 0.03 g or less. However, Sample No. 1 and Sample No.
10. As is clear from the comparison between Sample No. 2 and Sample No. 11, in Samples No. 10 and No. 11 having no peak at 1160 ± 40 cm ⁻¹ , the polishing step required 100 times or more. In addition, the sample showed a slightly larger amount of wear than the others, indicating that the characteristics and productivity were slightly inferior to those of Sample No. 1 and Sample No. 2.

Further, the cemented carbide (sample No. 12) conventionally used as a substrate has poor adhesion strength,
Based on the present invention, it has been confirmed that titanium or a titanium alloy is excellent as a substrate in a wear-resistant member.

Example 3 Ti-10% V-2% Fe having the shape of SGN422
Using a cutting tip made of a -3% Al alloy as a substrate, a cutting tool was produced by adjusting the time so that the thickness of the intermediate layer was 5 μm and the hard carbon film was 50 μm based on the conditions shown in Table 1 of Example 1 above.

For comparison, a silicon nitride sintered body of the same shape (containing 5% by weight of Al ₂ O ₃ and 3% by weight of Y ₂ O ₃ )
Was used as a substrate to form a hard carbon film under the same conditions as above, and a comparison was made.

Using these cutting tools, an aluminum-12% silicon alloy was used as a work material, and a cutting speed of 8% was used.
00m / min, feed 0.1mm / rev, cut 0.2
The cutting test was evaluated for 30 minutes in a dry system under the condition of mm, and the flank wear after the test was measured. as a result,
With the titanium alloy substrate of the present invention, the flank wear was 0.03.
mm, the work surface of the work material was glossy and beautifully finished. In addition, a silicon nitride sintered body base product of 0.04 m
m, and the machined surface of the work material was also beautifully finished.

Next, for each of the ten tools, an aluminum-12% silicon alloy having four grooves extending in the axial direction on the outer peripheral surface was used as a work material, and the cutting speed was 800 m.
/ Min, feed 0.1 mm / rev, cutting depth 0.2 mm, and as a result of examining the chipping resistance after cutting for 30 minutes in a dry system, there was no chipping in the product of the present invention.
In the tool comprising the silicon nitride sintered body substrate, four out of ten tools had defects, and it was confirmed that the titanium alloy substrate was excellent.

[0051]

As described in detail above, the wear-resistant member of the present invention has excellent adhesion strength between the hard carbon film and the substrate, and the film itself has excellent wear resistance. It can be seen that it is suitable for a flexible member and a sliding member. Further, since the present invention uses titanium or a titanium alloy as a substrate, it has excellent toughness, can prevent the substrate from being broken, and hardly causes chipping even when used for a cutting tool or the like. Further, by including microcrystalline diamond in the hard carbon film, the film surface after film formation is excellent in smoothness, and the film surface can be easily polished.

[Brief description of the drawings]

FIG. 1 is a schematic view for explaining the structure of a wear-resistant member of the present invention.

FIG. 2 is a diagram showing the results of Raman spectroscopic analysis of a hard carbon film according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Intermediate layer 3 Hard carbon film 4 Diamond 5 Metal carbide

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 14/00-16/56 C01B 31/00-31/36 C30B 29/04 F16C 33/00-33 / 28 B23B 27/14 B23P 15/28

Claims (1)

(57) [Claims] 1. The method according to claim 1, wherein the surface of the substrate made of titanium or a titanium alloy mainly containing titanium is coated with at least diamond and carbon.
A hard carbon film is coated via an intermediate layer containing silicon, the hard carbon film has a surface roughness (Rmax) of 2 μm or less, and has a Raman spectrum of 11 μm or less.
A wear-resistant member having a peak at 60 ± 40 cm ⁻¹ .