JPH06316763A - Formation of wear resistant hard film - Google Patents

Abstract

PURPOSE:To remarkably improve the wear resistance of a lightweight structural material such as an Al alloy without deteriorating its hardness and strength, in an ionization electrode type ion plating method by impressing pulse voltage on an ionization electrode under specified conditions. CONSTITUTION:At the time of forming CrN film on a substrate 2 of an Al alloy or the like by using an ion plating device, nitrogen is introduced into a vaccum reaction tank 1, and its pressure is regulated to a prescribed one. the material 5 (Cr-Ti alloy) to be evaporated in a crucible 3 is irradiated with accelerating electrons from an electron gun 4 and is heated and melted to selectively evaporate Cr. At this time, pulse voltage having >=100Hz frequency, >=10% duty ratio and >=40V maximum voltage is impressed on an ionization electrode 9 from a pulse power source 8. In this way, the optimum wear resistant hard film is formed on the substrate 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a wear resistant hard coating most suitable for a metal material required to be wear resistant.

[0002]

2. Description of the Related Art Al alloys, Mg alloys, Ti alloys, etc. are easy to be used as a lightweight structure for major structural materials related to space aircraft such as automobile parts, or various mechanical parts, dies and the like.
However, these lightweight materials have the drawback of being significantly inferior in wear resistance to steel materials. Therefore, there is a limit in applying these alloys to members that are subjected to severe friction and wear, and ideally, steel materials are often used where Al alloys or the like should be used. The surface hardening method is the most effective method for improving the wear resistance of an Al alloy or the like.

As a surface hardening treatment for Al alloys and the like, various plating methods such as hard alumite treatment, Ni plating and Cr plating have been put into practical use, but the hardness is Hv300 by alumite treatment.
Hv 600 to 700 by plating, and the film thickness is several tens of μm at most. As the demand for lightweight seating increases, surface hardening treatment with a thickness of a few mm shows durability against large impact and high surface pressure, and high hardness with a thickness of a few μm to maintain dimensional accuracy. Is required to be displayed.

120 for Al alloy, Mg alloy, Ti alloy, etc.
Some are age hardened at ℃ to 200 ℃,
When the temperature is 200 ° C. or higher, the hardness and strength decrease, and therefore, in order to surface-harden precision parts made of these alloys, it is required to process them at a low temperature of 200 ° C. or lower. To achieve these objectives, it is considered optimal to form a ceramic hard coating using the ion plating method, which enables film formation at a relatively low temperature. Radiant heat from and kinetic energy of ions,
The temperature of the metal material to be coated rises above 200 ° C.

On the other hand, Japanese Patent Application No. 03-347623
In this issue, an alloy that forms a solid solution or eutectic is used as an evaporation material, and by selectively evaporating a high vapor pressure metal,
It has succeeded in forming a film having a Hv of 1500 or more at a film forming temperature of 200 ° C. or less.

[0006]

However, Japanese Patent Application No. 03-
Even when the invention described in 347623 is used, the film forming temperature is 18
At about 0 ° C., the hardness of some Al alloys and Mg alloys standardized in JIS A7075P was unavoidable.

Therefore, an object of the present invention is to provide a method for forming a ceramic film having a high hardness at a lower temperature than the conventional surface treatment method for a metal material.

[0008]

As a result of intensive studies to solve the above problems, in a method for forming a hard coating on a metal substrate, an ion having an electrode for ionizing metal evaporated in a vacuum chamber Using a plating device and a power source capable of generating a pulse voltage at this electrode, a pulse voltage frequency of 100 Hz or more, a duty ratio of 10% at an inkjet station, and a maximum voltage of 40 V or more, the temperature is high and the hardness is high. It has been found that various ceramic coatings can be formed.

[0009]

In order to form a hard coating at a low temperature using the ion plating method, it is necessary to sufficiently ionize the evaporation material and at the same time reduce the radiation from the evaporation source. Radiation from the evaporation source includes radiation from the molten evaporation material and radiation from plasma generated by ionization. As for the former, a countermeasure is taken in Japanese Patent Application No. 03-347623, and the present invention solves the latter problem (reduction of radiation from plasma). In the conventional ionization electrode type ion plating method, a DC voltage is applied to the ionization electrode to generate plasma and ionize the evaporated metal.

However, in this method, since energy is always provided to excite the plasma, radiant heat from the plasma is large, and it is difficult to lower the temperature during film formation. However, the life of the plasma is 1 msec or more, and it is possible to continue the plasma discharge without constantly providing energy for plasma excitation. Therefore, even if energy is intermittently supplied to the ionization electrode by using the pulse power supply as the power supply of the ionization electrode, the discharge can be continued without extinguishing the plasma. Moreover, according to this, the energy supplied to the plasma as a whole can be made lower than that when a DC power source is used, so that the film forming temperature can be lowered.

The pulse conditions are somewhat different depending on the metal vaporized, the reaction gas, etc., but the frequency of the pulse voltage must be 100 Hz or higher to sustain the plasma. Lower than this will not last. Further, if the duty ratio, which is the time ratio for applying the voltage during one pulse cycle, is 10% or more, the plasma can be sustained regardless of the frequency. The maximum pulse voltage must be 40 V or higher. If it is lower than this, plasma is not generated. It is also possible to always apply a certain voltage as the base current and superimpose the pulse voltage on this.

However, in this case, it is meaningless if the total energy becomes equal to the DC applied voltage, so it is necessary to make the total energy not more than the DC applied voltage. further,
In order to smoothly ionize the low melting point metal, it is possible to install an electrode for supplying thermoelectrons in the vacuum chamber and supply thermoelectrons to the plasma region.

Basically, any metal material may be used as the surface coatable material.
2014P, A4032P, A6061P, A7075
Examples include age-hardening Al alloys including P, various Mg alloys, various Ti alloys, cold tool steels such as SKD11, and the like.

[0014]

EXAMPLES Next, examples of the invention will be described. First, an ionization electrode type ion plating device used in the film forming method of the present invention will be described. FIG. 1 is a schematic diagram of an ionization electrode type ion plating apparatus. In FIG. 1, reference numeral 1 is a vacuum reaction tank, 2 is a substrate, 3 is a crucible, 4 is an electron gun,
5 is a vapor deposition material, 6 is a substrate holder, 7 is a bias power source, 8
Is a pulse power source, and 9 is an ionization electrode. The difference from the conventional example is that a pulse voltage is applied to the ionization electrode 9 from the pulse power source 8 instead of the DC power source.

Example 1 CrN was formed into a film by using the ion plating apparatus shown in FIG. An Al alloy of JIS A7075P was used as an example of the substrate to be coated. The hardness of this alloy is Hv175 and the tensile strength is 58 kg.
f / mm ² . This Al alloy was washed with an organic solvent and then set in a vacuum reaction tank, and the pressure in the vacuum reaction tank was evacuated to 1.3 × 10 ⁻³ Pa or more. After reaching the target vacuum degree, heating was performed at 150 ° C. for 1 hour, and then Ar ion bombardment treatment was performed for 10 minutes. As the evaporation source of the metal for forming the film, Cr-having a molar concentration of Ti of 35%
A Ti alloy was used. The film forming conditions at this time were that nitrogen was introduced as a reaction gas at 20 cc / min, and the pressure was 0.13.
It was Pa. By applying accelerated electrons of 9 kV-150 mA to the above evaporation source, it was heated and melted, and Cr was selectively evaporated. A pulse voltage with a frequency of 500 Hz, a duty ratio of 30% and a maximum voltage of 60 V is applied to the ionization electrode,
An electric current of 6V-30A was applied to the thermionic electrode to vaporize Cr.
Was ionized. In addition, -5 with respect to the above Al alloy
A bias voltage of 0V is applied. Under such conditions, A
Although a nitride of Cr was produced on the surface of the 1-alloy, a film having a thickness of 4.5 μm was obtained by the film forming reaction for about 1 hour.
During film formation, the temperature was 150 ° C. When the Vickers hardness of the coating was measured with a load of 10 g, it was Hv1600. Moreover, the hardness of the substrate was Hv175, and no decrease in hardness was observed. The tensile strength of the substrate is 55 Kgf / m
It was slightly lower than m ² .

Example 2 Ti was used as a vapor deposition material, and only nitrogen was introduced as a reaction gas at 25 cc / min. Further, a Ti nitride film was formed under the same conditions as in Example 1 except that the pulse voltage conditions were a frequency of 300 Hz, a duty ratio of 50%, and a maximum voltage of 50V. The temperature during film formation was 170 ° C. Vickers hardness of coating is 10g load
It was Hv1650 when measured by. The hardness of the substrate was Hv175, and no decrease in hardness was observed.

(Example 3) 18 c of nitrogen was used as a reaction gas.
c / min, 15 cc / min of methane were introduced, the pulse voltage condition was frequency 300 Hz, duty ratio 40%,
C under the same conditions as in Example 1 except that the maximum voltage was set to 60V.
A carbonitride of r was formed into a film. The temperature during film formation is 160 ℃
Met. When the Vickers hardness of the coating was measured with a load of 10 g, it was Hv1700. The hardness of the substrate is H
No decrease in hardness was observed at v175, and the strength was 54 Kgf /
It was mm ² .

Comparative Example 1 A Cr nitride film was formed under the same conditions as in Example 1 except that the ionization electrode voltage was 50 V DC instead of pulse voltage. The temperature during film formation is 1
At 95 ° C, the film forming temperature was 45 ° C higher than that of the present invention. Therefore, the hardness of the substrate was reduced to Hv160, and the strength was 45 Kgf / mm ^2, which was 20% or more. When the Vickers hardness of the coating was measured with a load of 10 g, it was Hv1100.

[0019]

As described above, according to the present invention, the surface hardening treatment can be performed without lowering the hardness and strength of the lightweight structural material such as Al alloy, and the wear resistance of these members can be greatly improved. You can

[Brief description of drawings]

FIG. 1 is a schematic view of an ionization electrode type ion plating apparatus used in an example of the present invention.

[Explanation of symbols]

 1 Vacuum Reaction Tank 2 Substrate 3 Crucible 4 Electron Gun 5 Deposition Material 6 Substrate Holder 7 Bias Power Supply 8 Pulse Power Supply 9 Ionization Electrode

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[Procedure amendment]

[Submission date] September 14, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hard wear resistant hard coating most suitable for a metal material requiring wear resistance.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art Al alloys, Mg alloys, Ti alloys, etc. are easily used as lightweight structural materials for automobile parts, main structural materials related to space aircraft, various mechanical parts, dies and the like. However, these lightweight materials have the drawback of being significantly inferior in wear resistance to steel materials. For this reason,
There is a limit to applying these alloys to members that are subjected to severe friction and wear, and ideally, steel materials are often used where Al alloys or the like should be used. The surface hardening method is the most effective method for improving the wear resistance of an Al alloy or the like.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

As a surface hardening treatment for Al alloys and the like, various plating methods such as hard alumite treatment, Ni plating and Cr plating have been put into practical use, but the hardness is Hv300 by alumite treatment.
Hv 600 to 700 by plating, and the film thickness is several tens of μm at most. As the demand for lightweight materials increases, it will be durable to a large impact and high surface pressure.
There is a growing demand for a surface hardening treatment with a thickness of 1 μm and a treatment showing a high hardness with a thickness of several μm in order to maintain dimensional accuracy.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

However, Japanese Patent Application No. 03-
Even when the invention described in 347623 is used, the film forming temperature is 18
At about 0 ° C., some Al alloys and Mg alloys standardized in JIS A7075P inevitably suffered a decrease in hardness and strength.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

As a result of intensive studies to solve the above problems, in a method for forming a hard coating on a metal substrate, an ion having an electrode for ionizing metal evaporated in a vacuum chamber By using a plating device and a power source capable of generating a pulse voltage at this electrode, and setting the frequency of the pulse voltage to 100 Hz or more, the duty ratio to 10% or more, and the maximum voltage to 40 V or more, it is possible to achieve higher temperature and higher hardness. It has been found that a ceramic coating can be formed.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

The surface coatable material may be basically any metal material, but as a material which is particularly effective, A
2014P, A4032P, A6061P, A7075
Examples include age-hardening Al alloys including P, various Mg alloys, various Ti alloys, cold tool steels such as SKD11, and the like.

Claims (1)

[Claims] 1. A method for forming a hard coating on a metal substrate, which uses an ion plating device having an electrode for ionizing metal evaporated in a vacuum chamber, and a power supply capable of generating a pulse voltage at the electrode. , The pulse voltage frequency is 100Hz or more, and the duty ratio is 1
A method for producing a ceramic coating, wherein the maximum voltage is 0% or more and the maximum voltage is 40V or more.