JPH0794707B2 - Method for producing coating thin film with excellent wear resistance and corrosion resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is directed to abrasion resistance by sputtering, ion beam sputtering, electron cyclotron resonance sputtering, vacuum deposition or ion plating using a double boride-based vapor deposition material as a starting material. The present invention relates to a method for producing a coating thin film having excellent corrosion resistance.

[Prior Art] With the increase in performance of industrial machines, the requirements for wear resistance of structural parts used therein are becoming more and more strict. For example, the speeding up of machines causes the parts to be worn or damaged more than before. Therefore, in order to make the apparatus maintenance-free and highly accurate, parts having excellent wear resistance and good corrosion resistance are indispensable. Tool steel, high speed steel, steel materials such as stainless steel, non-ferrous alloys such as aluminum and copper, and cermets are used as materials for machine structures, but wear resistance accompanying recent high performance and high functionality of machines. It is not possible to comply with the requirements for corrosion resistance and corrosion resistance, and the development of new materials is required. For these requests,
Many ceramics and their composites have been developed, but they still have many problems in terms of reliability. Further, recently, a hard compound-type hard alloy having high strength, high corrosion resistance and high wear resistance, which uses Mo ₂ FeB ₂ type double boride as a hard phase and an iron alloy containing Cr and Ni as a binder phase, has been developed. It has been developed (see, for example, Japanese Patent Publication No. 60-57499). This double boride-based hard alloy has sufficient strength as a structural material, is not only excellent in wear resistance and corrosion resistance, but also has little wear of itself by sliding friction, and less wear of the mating material. The feature is that mutual wear can be further reduced by using common gold, which is generally disliked. In addition, it has excellent wear resistance to powder and granules, excellent characteristics at high temperatures, excellent corrosion resistance to non-ferrous metals, and is based on iron, and its coefficient of thermal expansion is close to that of steel. Therefore, it has many characteristics such as easy joining with steel materials, and magnetic properties can be changed by changing the composition. This complex boride-based hard alloy is produced by a so-called powder metallurgy method, in which raw material powders are crushed, mixed, shaped, and then sintered, as proposed in Japanese Patent Publication No. 60-57499. Is used in sintered bodies. In many cases, wear-resistant members and parts used in various devices and machines often require wear resistance and other characteristics in a part of them, and it is difficult to machine such parts with complicated shapes. Therefore, it is not economically advantageous to construct the whole with this alloy. Therefore, a method of making a thin sheet of this alloy by sintering and then brazing it to steel etc. and then diffusion bonding, or a method of directly joining the sheet to steel etc. by sinter bonding (Japanese Patent Publication No. 62-8496) and thermal spraying Method for forming the hard alloy coating on the surface of the substrate by the method described in JP-A-63-195
254) etc. have been proposed. However, all of these methods form a film having a thickness of about 0.1 mm or more.

In addition, magnetic disks and the like are rapidly growing as magnetic recording materials, but magnetic disks repeatedly contact and float with a magnetic head for a long period of time, so a protective film is coated on the magnetic thin film to prevent damage or deterioration of the magnetic layer. There is. As the protective film, there are Pb, CU, Ti, In, Sb, Au, Pt, Ag, C, BN, SiC, etc.The protective film is formed by sputtering, vacuum deposition, ion plating, CVD. and so on. Among these, a carbon thin film formed by sputtering is most often used as the protective film. This is because the magnetic properties of the magnetic film formed by sputtering are excellent, and the thin film formed by the same sputtering is continuously used. This is because the lubricating performance of carbon is high. Then, the protective film can be continuously formed by the same method as the magnetic film formation, and the economical efficiency and the productivity can be improved.

However, this sputtered carbon is not sufficient for use in a severe environment. That is, in a CSS (Contact start stop) test for evaluating the durability of a magnetic disk, there is a problem in that the magnetic recording performance of the magnetic layer deteriorates after 20,000 times and the environment resistance at high humidity and high temperature is low.

Furthermore, in terms of magnetic recording performance, sputtering is the mainstream for forming a magnetic layer, and it is advantageous in terms of economy and productivity to continuously form a protective film by a sputtering method. Has a drawback in that it easily generates dust that causes a magnetic recording error.

[Problems to be Solved by the Invention] The above-mentioned double boride-based hard alloy has excellent properties as a wear-resistant material, but in the ultra-small machine parts and electronic device devices, which are increasing rapidly in recent years, Thin, for example
A film with a thickness of 100 μm or less and various excellent properties similar to those of this sintered body is now required.

Further, when this hard alloy is applied only to the part requiring wear resistance, the formation of the hard alloy layer by the conventional technique is usually performed at a high temperature of 1,000 ° C. or higher, so that the deformation or deterioration of the bonding base material There is an unavoidable case where the original characteristics cannot be fully exhibited, and a hard thin film formed at a low temperature is required. Further, application to a base material having poor heat resistance, particularly a plastic material is also desired.

On the other hand, in the case of a magnetic disk, it is required to develop a protective film that replaces sputtered carbon and that has properties such as head crush resistance, abrasion resistance, environment resistance, and magnetic property independence from the underlying magnetic thin film. . In this case as well, a thin film having the above-mentioned abrasion resistance and corrosion resistance is required, and further, a thin film formed at a low temperature is required so as not to damage the underlying magnetic film.

Therefore, the present invention provides a structural abrasion resistant member or a magnetic recording material with a thin film having a wear resistance and corrosion resistance of 100 μm or less which can be formed even at a low temperature.

[Means for Solving the Problems] The present invention has been made to solve the above problems, and is a matrix composed of one or more elements or alloys selected from Fe, Cr, Co, and Ni. In the M _x N _y B type (hereinafter M,
N is a metal, x and y are stoichiometric values required for M and N to form a compound) 40 to 99% by weight of compound boride (hereinafter,%)
Is a heavy boride-based hard alloy source (deposition source and target), wherein M is Mo.
And / or W and N are composed of one or more elements selected from Fe, Cr, Co and Ni, and have a B content of 2 to 8% and a Mo and / or W content of the source. , (Mo and /
Or W) / B in a molar ratio range of 0.50 to 1.50, with the balance being one or more elements or alloys selected from Fe, Cr, Co, and Ni, and unavoidable impurities. A hard metal alloy source is manufactured by a powder metallurgy method or the like, and using this as a starting material, a thin film is formed on a substrate by sputtering, ion beam sputtering, electron cyclotron resonance sputtering, vacuum deposition or ion plating.

Furthermore, in order to improve wear resistance and corrosion resistance,
One or more elements selected from Fe, Cr, Co, Ni and Mo, W, C
A matrix of M _x N _y B type (where M is an alloy of an alloy with one or more elements selected from u, Ti, V, Nb, Ta, Hf, Zr and Si)
Mo and / or W and one or more elements selected from Ti, V, Nb, Ta, Hf and Zr, N is one or more elements selected from Fe, Cr, Co and Ni) A complex boride-based hard alloy source containing 40 to 99% of complex boride having a B content of 2 with respect to the source.
.About.8%, Mo and / or W content is within a range of satisfying 0.50 to 1.50 in a molar ratio of (Mo and / or W) / B, and Cu, Ti, V, Nb, Ta, Hf, Zr , The total content of one or more elements selected from Si is 0.5 to 25%, and the balance is Fe, Cr, Co, Ni
A hard metal alloy source of double boride based on one or more elements or alloys selected from among the above and unavoidable impurities is manufactured by powder metallurgy etc., and is used as a starting material for sputtering, ion beam sputtering, electron A thin film is formed by cyclotron resonance sputtering, vacuum deposition or ion plating.

Here, the amount of the complex boride is set to 40 to 99% because sufficient abrasion resistance cannot be obtained when the amount of the complex boride is less than 40%.
If it exceeds%, the strength of the material is insufficient and handling becomes difficult.

B constituting boride has a B content of 2% with respect to the entire source.
If it is less, the abrasion resistance of the formed thin film is insufficient, and if B exceeds 8%, the strength of the thin film is lowered and the purpose cannot be achieved. Mo and W are the main elements forming the double boride, and the content of Mo and / or W is less than 0.50 in the molar ratio of (Mo and / or W) / B, or 1.50. If it exceeds, the strength of the formed film will be insufficient, and in particular, the abrasion resistance of the thin film formed on the soft substrate will be poor, so the range was made 0.50 to 1.50. Further, the preferable range for improving the strength of the formed film and the abrasion resistance is 0.60 to 1.40.

Each element of Ti, Zr, Hf of IVa group and V, Nb, Ta of Va group of the periodic table is substituted with a part of Mo and / or W in M _x N _y B type complex boride, contributes to the hardness increase of the _x N _y B-type complex boride, some of them are dissolved in the matrix, leading to improving the wear resistance of the coating film. The above effect can be seen from the addition of 0.5% of these elements, but 2
Even if 5% or more is added, the effect as much as the added amount is not recognized. Further, these elements show similar effects not only when added alone but also when added in combination. Therefore, Ti, Zr,
The total amount of Hf, V, Nb, and Ta added is 0.5 to 25.
%.

Si and Cu form a solid solution in the matrix of the present hard alloy source, and contribute to the improvement of the oxidation resistance and corrosion resistance of the coating thin film, respectively. If the addition amount of Si and Cu is less than 0.5%, the above effect is not observed, and if it exceeds 25%, the oxidation resistance and corrosion resistance are improved, but the coating thin film is embrittled. Si and Cu have the above effect even when added in combination with Ti, Zr, Hf, V, Nb, and Ta. Therefore, the addition amount of Si and Cu is 0.5 to 25 as the total of Ti, Zr, Hf, V, Nb, Ta, Si and Cu.
%.

The manufacturing method of the present hard alloy source will be described below.

The hard alloy source is Fe-B or Fe as a boron source.
-B type alloy powder, Ni-B or Ni-B type alloy powder, Co-
B or Co-B based alloy powder, ferroboron powder, nickel boron powder, Fe, Cr, Co, Ni, Mo, W, Ti, V, Nb, Ta, Hf, Zr boride powder, or B simple substance powder is used. , These powders and elemental metal powders of Fe, Cr, Co, Ni, Mo, W, Ti, V, Nb, Ta, Hf, Zr, Si, Cu, or alloy powders containing two or more of these elements. Blend to a specified composition, add a small amount of carbon powder or carbide to reduce the oxide film on the powder surface if necessary, and mix these powders in an organic solvent using, for example, a vibrating ball mill. After wet mixing and pulverization with
It is manufactured by performing granulation / molding, subjecting the molded body to reaction sintering in a non-oxidizing atmosphere, and forming an M _x N _y B type double boride during the sintering. Reactive sintering is usually 900-1,500 ℃
For 1 to 120 minutes. As the sintering atmosphere, a vacuum or a non-oxidizing atmosphere such as a reducing gas or an inert gas is used to prevent the powder from being oxidized.

The density of this hard alloy source after sintering is preferably as high as possible in order to obtain a uniform coating thin film, but if it has a density of 55% or more of the true density, it does not hinder handling and is practically usable. Is no problem.

55% when the sintering temperature is less than 900 ℃ and the sintering time is less than 1 minute
The above density was not obtained, and even if it was sintered at 1,500 ° C for 120 minutes, no such effect was observed. Therefore, the temperature and time of the reaction sintering are 900 to 1,500 ° C. and 1 to 120 minutes.

Although a general sintering method has been described as a method for producing the present hard alloy source, in order to achieve the object, a hot isostatic pressing method, a hot pressing method, an electric current sintering method, or the like can be used during sintering.
If _x N _y B-type sintering method in which formation reaction occurs in complex boride may be any sintering method.

By using the thus-produced complex boride-based hard alloy source as a starting material, by sputtering, ion beam sputtering, electron cyclotron resonance sputtering, vacuum deposition or ion plating on any substrate,
Form a thin film of Å ~ 100 μm.

In sputtering, a film is formed on a substrate under a vacuum of 10 ^-2 to 10 ^-4 Torr using a starting material as a cathode target. An inert gas such as Ar can be used as the discharge gas, and both direct current and high frequency can be used as the discharge energy. In sputtering, the current mainstream is magnetron sputtering, and it is possible to increase the sputtering efficiency by strengthening the magnetic field on the target. Further, by applying a bias voltage to the substrate, the composition control of the film can be facilitated. An ion beam or electron cyclotron resonance can be used as an energy source for sputtering. Ion beam sputtering can form a film under plasma-free conditions at a high crimson level of 10 ^-4 to 10 ^-6 Torr, and can form a high-quality film that does not contain discharge gas. These may be used together to form a film.

Vacuum evaporation, resistance heating, induction heating, electron beam heating, molecular beam heating, ion beam heating, and the like can be used as evaporation means for vapor deposition raw materials in ion plating.
As a plasma source for ion plating, direct current, high frequency, arc, microwave or the like can be applied, and a method of applying a bias voltage to the substrate can also be applied.

As the evaporation material, a more stable film composition can be obtained by individually evaporating each elemental component of the multi-component alloy, or by sintering or solidifying the component powder as a starting material rather than using the component element gas. The object of the present application is achieved. In these thin film forming methods, heating may be performed during film formation of the base material or the substrate. In addition, low temperature film formation is performed on substrates with poor heat resistance such as plastic materials.
A film can be formed even at 0 ° C or lower, and good adhesion can be obtained.

It is desirable to change the film thickness depending on the purpose of use, but 50Å
-100 μm is suitable. If the thickness is less than 50Å, the wear resistance and the corrosion resistance cannot be improved, and even if it exceeds 100 μm, the desired effect is not improved so much and it takes a long time to form the film, which is economically disadvantageous. Further, it is necessary to properly select the coating film thickness depending on the purpose of use. 0.1 to 100 μm is suitable for ordinary machine parts and tools. This is because if it is thinner than 0.1 μm, it is impossible to prevent wear and severe wear without lubrication. 50-1,000Å is suitable for wear-resistant coatings against wear and light wear under fluid lubrication or for protective films of magnetic recording materials.

[Examples] The present invention will be described in more detail with reference to Examples.

Example 1 For the composition No. 1 to have the composition shown in Table 1, Fe-
13.5% B-5.1% Cr alloy powder, Ni-18.2% for No. 2
For B alloy powder, No. 3, MoB powder was the main raw material, and Ni, Cr, Mo, Co, and W metal powders were mixed with them, and 5% paraffin and 0.4% graphite powder were added as lubricants to it. Acetone is used as a solvent, pulverized and mixed with a wet ball mill for 18 hours, and the dried mixed powder is then hydraulically pressed.
The powder was compacted using a die and sintered in vacuum at 1,230 to 1,290 ° C. for 30 minutes to produce a φ80 mm × 5 mm complex boride-based hard alloy source.

Using this source, a thin film was formed by ion plating, and wear resistance and corrosion resistance were examined.

The thin film forming conditions are as follows.

Method: DC excitation ion plating Ar gas pressure; 1X10 ^-3 Torr Evaporation source heating source; Approximately 40 mm square x 10 mm SUS440C plate under electron beam conditions
10 μm coating The same SUS440C cylindrical ring (outer diameter: φ25.
The friction coefficient and the wear amount were measured by a cylindrical friction wear test (manufactured by Shinko Seiki Co., Ltd.) using 6 mm, inner diameter φ20 mm, height 13 mm). All the contact surfaces of the plate and ring samples were lapped, and the surface roughness was Rmax of 0.05 to 0.
It was set to 06 μm. The results are shown in Table 2. The measurement conditions are as follows.

Friction condition: Dry load: 30Kg (0.15Kg / mm ² ) Slip velocity: 2.39m / s Slip distance: 3,000m Comparative material: WC-20% Co-based cemented carbide All coating materials of the present invention are cemented carbide The friction coefficient was lower and the wear amount was much lower than that of cemented carbide.

Furthermore, about 0.3 ml of 3% saline solution was placed on the plate-shaped specimens of D20 and SU440C, which are comparison materials with these coating materials.
The mixture was dropped and left in a constant temperature bath at 80 ° C for 24 hours to examine the corrosion state. As a result, significant discoloration was observed in the traces of the droplets of saline solution of D20, but a slight amount of salt remained in the traces of the droplets in the stainless steel and the material of the present invention. Scarcely visible to the naked eye. Thus, like the source material, the coating material of the present invention has wear resistance higher than that of cemented carbide and corrosion resistance equivalent to SUS440C.

Example 2 A hard alloy consisting of B: 6.1%, Mo: 44.5%, Cr: 20.5%, Ni: 8.2% and the balance Fe was used as a cathode target of size 157 mm x 457 mm x 6 mm, and a 3.5 inch size Ni-P plated Al alloy disk was used. Nine sheets are mounted on a substrate holder and an in-line sputtering device is used to form Cr of the underlayer of 1500Å and Co-Ni-Cr alloy of the magnetic layer of 600Å on both sides, and then continuously form 300Å protective film on both sides. Let The sputtering for forming the protective film was performed as follows.

Method: DC magnetron sputtering Ar gas pressure; 1X10 ^-2 Torr power; 2W / cm ^{2 In} addition, 50 Å of polyfluorocarbon as a lubricating film of a thin film magnetic disk was applied.

Example 3 B: 6.1%, Mo: 32.6%, W: 4.2%, Cr: 24.9%, Ni: 1.0%, balance
A hard alloy made of Fe was used as the cathode target of the same size as in Example 2, the same sputtering apparatus and substrate as in Example 2 were used, and the underlying Cr was 2,000Å and the magnetic layer Co-Cr-T was used.
After forming an alloy a of 700Å, a protective film was continuously formed using a hard alloy cathode target. The sputtering conditions and the formation of the lubricating film were the same as in Example 2.

Comparative Example As in Example 2, a 3.5-inch size Ni-P plated Al alloy magnetic disk substrate on which a magnetic layer was formed was subjected to 300 Å carbon sputtering as a protective film.

The characteristics of the magnetic disks prepared in Examples 2 and 3 and Comparative Example were tested for the following items.

1) Magnetism of protective film: Measured with a VSM (BHV-50) manufactured by Riken Denshi with a maximum magnetic field of 5000 Oe and a size of 10 × 10 mm.

2) Durability: Using a Fujitsu CSS tester, using a head with a flying height of 0.15 μm and a weight of 9.5 g, at a disk maximum rotation speed of 3,600 rpm, a reduction in head output after 20,000 CSS tests and a disk The frictional force with the head at 0.09 rpm was measured.

3) Corrosion resistance: 80 as a reliability evaluation of magnetic disk
The increase in misbits after standing for 1200 hours in an atmosphere of ℃ and relative humidity of 80% was measured by a Pro Quip certifier.

The results are shown in Table 3. The magnetic disk coated with the material of the present invention showed no decrease in head output before and after the CSS test, and the increase in frictional force and the increase in misbit after the corrosion test were less than those of the comparison material coated with sputtered carbon.

The magnetism was 0.7 × 10 ⁻⁵ emu or less in both the example and the comparative example, and it was confirmed that both were non-magnetic.

[Effects of the Invention] The coating thin film obtained by the method of the present invention has excellent wear resistance and corrosion resistance as well as the sintered hard alloy, and adheres evenly and firmly to a member having a complicated shape. Moreover, since there is no alteration, deformation or dimensional change of the base material as in the case of thermal spraying or diffusion bonding, a highly accurate coating thin film can be obtained after finishing. With such an extremely thin film, wear resistance and corrosion resistance,
Since it can exhibit the same performance as a sintered hard alloy, its economic effect is great. Further, it can be used as a thin film formed on an organic material such as a resin as well as a non-ferrous material other than a steel material and ceramics such as glass.

Further, as shown in Table 3, when the thin film is coated by the method of the present invention, the magnetic recording characteristics of the magnetic film are not deteriorated, and the wear resistance and corrosion resistance of the magnetic disk can be improved. In addition, the formed thin film is non-magnetic and satisfies the conditions as a protective film for a magnetic recording material, and there is no contamination of the vacuum chamber as in carbon sputtering. It is possible to reduce the generation of dust due to the above, reduce defects such as miss bit due to the reliability of the magnetic recording material due to dust, and improve the yield.

Claims (3)

[Claims] 1. A matrix of M _x N _y B type (hereinafter, M and N are metals and x and y are M in a matrix composed of one or more elements or alloys selected from Fe, Cr, Co and Ni. , N represents the stoichiometric value required to form a compound) 40 to 99% by weight of compound boride
(Hereinafter,% is% by weight) is a complex boride-based hard alloy source (deposition source and target), wherein M is Mo.
And / or W and N are composed of one or more elements selected from Fe, Cr, Co and Ni, and have a B content of 2 to 8% and a Mo and / or W content of the source. , (Mo and /
Alternatively, W) / B is also in a range satisfying a molar ratio of 0.50 to 1.50, and the balance is a compound boron containing one or more elements or alloys selected from Fe, Cr, Co and Ni and inevitable impurities. Method for producing a coating thin film having excellent wear resistance and corrosion resistance, which is characterized by being formed by sputtering, ion beam sputtering, electron cyclotron resonance sputtering, vacuum deposition or ion plating on a substrate using a hard metal alloy source as a starting material. . 2. At least one element selected from Fe, Cr, Co and Ni, and Mo, W, Cu, Ti, V, Nb, Ta, Hf, Zr and Si. In a matrix consisting of an alloy with one or more elements,
M _x N _y B type (hereinafter M and N are metals, x and y are stoichiometric values required for M and N to form a compound) compound boride
A complex boride-based hard alloy source containing 99% by weight (hereinafter,% is% by weight), wherein M is Mo and / or W.
Ti, V, Nb, Ta, Hf, Zr consists of one or more elements selected, N consists of one or more elements selected from Fe, Cr, Co, Ni B content is 2-8%, Mo
And / or W content is (Mo and / or W) / B
Is within the range of satisfying 0.50 to 1.50 in terms of the molar ratio of
The total of one or more elements selected from Cu, Ti, V, Nb, Ta, Hf, Zr and Si is 0.5 to 25%, and the balance is selected from Fe, Cr, Co and Ni 1 It is characterized in that it is formed by sputtering, ion beam sputtering, electron cyclotron resonance sputtering, vacuum deposition or ion plating on a substrate using a double boride hard alloy consisting of one or more elements or alloys and unavoidable impurities as a starting material. A method for producing a coating thin film having excellent wear resistance and corrosion resistance. 3. The double boride-based alloy source according to claim 1, wherein the Mo and / or W content is within a range of 0.60 to 1.40 in a molar ratio of (Mo and / or W) / B. A method for producing a coating thin film having excellent wear resistance and corrosion resistance, which is formed by sputtering, ion beam sputtering, electron cyclotron resonance sputtering, vacuum deposition or ion plating on a substrate using as a starting material.