JPH05239620A - Manufacture of corrosion resistant hard multilayer film - Google Patents

Abstract

PURPOSE:To provide the method for manufacturing a hard film by a physical vapor deposition method by which pinholes in a film are reduced and its corrosion resistance can be improved. CONSTITUTION:In the method for forming a hard film of one kind among the nitrides, carbides and carbonitrides of Ti, Zr, Hf, V, Nb, Ta and Cr on the surface of metal by a physical vapor deposition method, in the process of forming the hard film, the metal of Ti, Zr, Hf, V, Nb, Ta or Cr is vapor- deposited on the hard film to obtain a product having a multilayer structure of the hard film and the metallic layer and in which the outermost layer is constituted of the hard film. A ferroxyl test by JIS H 8663 was executed and its corrosion resistance was evaluated by the density of corrosive pores, and, as a result, the fact that it has remarkably been improved was recognized compared to the case in which the hard layer has not been interposed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has few pinholes,
In particular, the present invention relates to a method for producing a corrosion-resistant hard multilayer film having excellent corrosion resistance.

[0002]

2. Description of the Related Art Generally, in order to impart wear resistance and corrosion resistance to metal materials such as high speed steel and die steel, a method of forming a coating having wear resistance and corrosion resistance on the surface of the metal material is known. It is taken. As a method of forming, Cr, Ni
A plating method capable of forming a dense coating having a large thickness, a thermal spraying method performed by spraying a hard compound containing a metal oxide or carbide as a main component onto the surface of a metal material, and a hard compound. It is known that a vapor phase deposition method or the like that can form a film on a metal material densely and can obtain high smoothness is sufficient. In any of these methods, sufficient film properties, particularly, In order to improve the corrosion resistance, it is necessary to remove the pinholes present in the coating. Then, to remove this pinhole,
Measures are taken to prevent the pinholes from reaching the metal material as the base material by densifying the film structure to reduce the pinholes themselves or by increasing the film thickness of the film. Among the vapor phase deposition methods, the physical vapor deposition method (PVD), in particular, is capable of low-temperature treatment, so that bluntness and dimensional deformation of the metal material can be eliminated. Therefore, a method of forming a hard coating on a metal material by such a physical vapor deposition method has become widespread.

[0003]

However, when a steel material having a coating film formed by a plating method is used as a part in a machine or the like where it vibrates violently or where a large pressure load or impact is applied, There is a problem that hardness is insufficient, and in the thermal spraying method, the rate of pinholes is high due to the thermal spraying method itself, and the surface roughness of the coating becomes rough, so that a member requiring smoothness is required. There is a problem that it cannot be used as. Further, the physical vapor deposition method can densify the hard coating and improve the wear resistance, but this method also has the problem that fine pinholes still exist in the coating and are not sufficient in terms of corrosion resistance. is there.

It is an object of the present invention to provide a method for producing a hard coating by physical vapor deposition, which can reduce pinholes in the coating and improve corrosion resistance.

[0005]

Means for Solving the Problems The present inventor has conducted extensive research to solve the above problems and achieve the above objects, and preferably, between the hard coatings, preferably the same kind of metal as that used for the hard coating formation. The inventors have completed the present invention by finding that the purpose can be achieved by interposing a metal layer. That is,
The present invention uses Ti, Zr, H on a metal surface by physical vapor deposition.
In a method for forming a hard coating of any one of f, V, Nb, Ta or Cr nitrides, carbides or carbonitrides, Ti used for film formation during the formation of the hard coating. , Zr, Hf, V, Nb, Ta or Cr, the same kind of metal as that used for film formation is vacuum-deposited on the hard coating to form a multilayer structure of the hard coating and the metal layer, A method for producing a corrosion-resistant hard multilayer film, wherein the lowermost layer is the hard coating.

Examples of the metal base material to which the present invention is applied include case-hardening steel such as S15C, structural steel such as S45C, spring steel such as SUP10, and bearing steel such as SUJ2.
Nitrided steel such as SACM1, hot working steel such as SKD6, cold working steel such as SKD11, high speed tool steel such as SKH51, heat resistant steel such as SUS301, and SU
Various steels such as corrosion resistant and acid resistant steels such as S410, super alloys, A7
Examples include metals such as aluminum alloys such as 075P.

The hard coating is made of Ti, Zr, Hf, V, N
One of b, Ta or Cr nitrides, carbides or carbonitrides is selected and formed.

As the metal layer to be interposed between the hard coatings,
Ti, Zr, Hf, which are used for forming hard coatings,
A metal selected from V, Nb, Ta or Cr and used in the film formation is used.

The outermost layers of the coating are Ti, Zr, Hf, V,
It must be a hard coating of the same type as the hard coating used for film formation among Nb, Ta or Cr nitrides, carbides and carbonitrides.

As the physical vapor deposition method in the present invention, an ion plating method, a sputtering method, or an ion implantation method can be applied. The metal evaporation method used in the ion plating method may be resistance heating, electron gun heating, or cathode arc method, and the evaporated metal ionization method may be arc discharge, glow discharge, high frequency discharge, or the like. But it's okay.

As the reaction gas, nitrogen, ammonia, or a mixed gas thereof is used in the case of nitride, and methane, ethylene, and
At least one kind of chain hydrocarbon such as acetylene or propane is used, and in the case of carbonitride, at least one kind of chain hydrocarbon as described above and a gas selected from nitrogen or ammonia are used. The pressure when introduced into the reaction tank may be in the range of 0.1 to 20 Pa.

The evaporation method for forming the metal layer may be such that the metal is ionized or non-ionized. However, when the metal is ionized, it is better not to apply a bias voltage to the substrate. Further, during the film formation of the metal layer, it is preferable to stop the supply of the respective reaction gases for forming the nitride, the carbide and the carbonitride.

[0013]

Function: Ti, Zr, Hf, V, Nb, Ta or Cr
The nitrides, carbides, and carbonitrides of
It is an excellent wear resistant material. The crystal orientation, crystal grain size, residual stress, etc. of these hard compounds change depending on the film forming conditions by the physical vapor deposition method. In the case of physical vapor deposition, the film has a strong crystallographic orientation, so if the film forming conditions remain constant until the film formation is completed, a film is likely to be formed in the crystallographic orientation direction, and the film is not formed in the direction of filling the pinhole. It becomes difficult to grow.
Therefore, by vacuum-depositing a metal during the film formation, the generation of pinholes can be significantly reduced. This is presumably because the presence of the metal layer hinders the continuous growth of the hard coating and the formation of new nuclei reduces the number of pinholes reaching the metal surface.

When a bias voltage is applied during the formation of the metal layer, the metal layer becomes a columnar crystal structure, which lowers the mechanical strength and at the same time deteriorates the corrosion resistance. Therefore, when the metal is ionized, It is better not to apply a bias voltage to the substrate. Also, in the state where the reaction gas is supplied,
This is because the metal and the gas react with each other and the bias voltage is not applied to the substrate, so that the film becomes a film having many holes and the corrosion resistance is deteriorated.

The hard coating and the metal layer have a greater effect on the corrosion resistance as the number of laminated layers increases, but Ti, Zr, Hf, V,
At least one metal layer is required for every 5 μm in the Nb, Ta or Cr nitride, carbide or carbonitride coating. This is because the effect of pinhole reduction is small when the film thickness of the hard coating is 5 μm or more, and the thickness of the metal layer is preferably 1 μm or less in view of the mechanical strength of the coating.

The hard coat is used as the outermost layer because if the metal layer is a metal layer, the hardness is low and the friction coefficient is high, so that the wear resistance is reduced.

[0017]

EXAMPLES Next, examples of the present invention will be described. Example 1 Using a vacuum arc discharge type ion plating device, a square steel plate (SUS304) having a thickness of 1 mm and a side length of 100 mm was used as a substrate for forming a multilayer coating film, and after washing with an organic solvent, , Installed in the vacuum reaction tank of the device. Using Ti as a metal for forming the nitride film, first, after the pressure in the vacuum reaction chamber was set to a vacuum of 2 × 10 ⁻³ Pa or less, cleaning and heating were performed by Ti ion bombardment to form a TiN film. Start. The reaction condition at this time is to introduce only nitrogen as a reaction gas into the reaction tank,
The pressure is 4 Pa. A current of 70 A is passed through Ti, which is a metal evaporation source, to release Ti ions from the Ti target by vacuum arc discharge. On the other hand, a bias voltage of -300V is applied to the steel substrate. At this time, the temperature of the steel substrate is 340 ° C. The film formation reaction was carried out for 20 minutes under these conditions, and when the film thickness reached 1.5 μm, the supply of nitrogen gas was stopped and the bias voltage was set to 0 V.
And the current flowing through the Ti target remains unchanged.
Metal deposition was performed. After performing this treatment for 5 minutes,
The above TiN film forming process was performed again. By repeating such an operation for 70 minutes, a five-layer structure of a TiN layer and a Ti layer was obtained, and a product having a total film thickness of 5 μm was obtained.

A corrosion resistance test was conducted on the obtained product according to J
Conducted a ferroxil test according to ISH 8663,
The corrosion resistance was evaluated by the corrosion hole density. The results are shown in Table 1. Comparative Example 1 Example 1 except that the metal layer was not formed during film formation.
A product having a single-layer coating having a film thickness of 4.5 μm was produced by the same treatment as described in (1), and an evaluation test was conducted in the same manner as in Example 1. The results are shown in Table 1. Example 2 Using Cr as a metal evaporation source, a product with a film thickness of 5.2 μm was manufactured by the same process as in Example 1 so as to form a CrN coating film and a Cr metal layer, and then in the same manner as in Example 1. The evaluation test was performed. The results are shown in Table 1. Comparative Example 2 A product having a single-layer coating having a film thickness of 5.0 μm was produced in the same manner as in Example 2 except that the Cr metal layer was not formed during film formation, and the same procedure as in Example 1 was performed. An evaluation test was conducted. The results are shown in Table 1. Example 3 Using Ti as a metal evaporation source and using methane as a reaction gas so as to form a TiC film and a Ti metal layer, the same process as in Example 1 was performed to manufacture a product having a film thickness of 4.7 μm. Then, the evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
Shown in. Comparative Example 3 A product having a single-layer coating having a film thickness of 4.5 μm was produced in the same manner as in Example 3 except that the Ti metal layer was not formed during film formation, and in the same manner as in Example 1. An evaluation test was conducted. The results are shown in Table 1. Example 4 Using Zr as a metal evaporation source, a product having a film thickness of 6.4 μm was manufactured in the same manner as in Example 1 so as to form a ZrN coating film and a Zr metal layer, and the same as in Example 1. The evaluation test was performed. The results are shown in Table 1. Comparative Example 4 A product having a single-layer coating with a thickness of 6.1 μm was produced by the same treatment as in Example 4 except that the Zr metal layer was not formed during film formation, and in the same manner as in Example 1. An evaluation test was conducted. The results are shown in Table 1. Example 5 Hf was used as a metal evaporation source and methane and nitrogen were used as reaction gases in the same manner as in Example 1 so as to form the HfCN coating and the Hf metal layer, and a product having a film thickness of 5.5 μm was obtained. Was manufactured and an evaluation test was conducted in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 5 A product having a single-layer coating with a film thickness of 4.9 μm was produced in the same manner as in Example 5, except that the Hf metal layer was not formed during film formation. An evaluation test was conducted. The results are shown in Table 1. Example 6 Using Nb as a metal evaporation source, a product having a film thickness of 3.7 μm was manufactured by performing the same process as in Example 3 so as to form the NbC coating film and the Nb metal layer, and in the same manner as in Example 1. The evaluation test was performed. The results are shown in Table 1. Comparative Example 6 A product having a single-layer coating with a film thickness of 3.5 μm was produced by the same treatment as in Example 6 except that the Nb metal layer was not formed during film formation, and in the same manner as in Example 1. An evaluation test was conducted. The results are shown in Table 2. Example 7 Ta was used as a metal evaporation source, and a TaN film and a Ta metal layer were formed in the same manner as in Example 1 to form a film having a thickness of 1
A product having a thickness of 0.5 μm was manufactured and an evaluation test was conducted in the same manner as in Example 1. The results are shown in Table 2. Comparative Example 7 A product having a single-layer coating with a film thickness of 9.5 μm was produced in the same manner as in Example 7, except that the Ta metal film was not formed during film formation, and the same procedure as in Example 1 was performed. An evaluation test was conducted. The results are shown in Table 2. Example 8 V was used as a metal evaporation source, and the same treatment as in Example 1 was performed so as to form a VN coating and a V metal layer, and the film thickness was 3.8 μm.
m product was manufactured and the evaluation test was performed in the same manner as in Example 1. The results are shown in Table 2. Comparative Example 8 A product having a monolayer film with a thickness of 3.6 μm was produced in the same manner as in Example 8 except that the V metal layer was not formed during film formation. An evaluation test was conducted. The results are shown in Table 2.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

EFFECTS OF THE INVENTION Since the present invention has the metal coating interposed between the hard coatings, the pinholes in the coating can be reduced, and the corrosion resistance can be improved.

Claims (1)

[Claims] 1. Ti, Z on a metal surface by physical vapor deposition
In the method for forming a hard coating of any one of a nitride, a carbide or a carbonitride of r, Hf, V, Nb, Ta or Cr, in the course of forming the hard coating,
Ti, Zr, Hf, V, Nb, T used for film formation
A method for producing a corrosion-resistant hard multilayer film, wherein a metal of a or Cr is vacuum-deposited on the hard film to form a multilayer structure of the hard film and a metal layer, and the outermost layer is the hard film.