JPH0881764A - Vacuum deposition method - Google Patents

Abstract

PURPOSE: To stabilize the arc discharge and improve the vapor deposition efficiency at the time of conducting the vacuum deposition with a low-m.p. metal as a cathode by laying a cover on a tip of the cathode opposed to an anode to prevent the deformation and melting of the part. CONSTITUTION: An anode 2 and a long-sized low-m.p. metal such as lead, tin and zinc as a cathode are opposed in a vacuum vessel, a DC voltage is impressed on both electrodes to generate an arc, and the metal from the cathode 3 is vapor-deposited on a material 4 to be coated. In this case, a cover 40 consisting of a metal having a higher m.p. than the metal constituting the cathode 3 is laid on the tip of the cathode 3, and then an arc is generated. Any material capable of protecting the low-m.p. metal of cathode 3 can be used for the cover 40, and the stainless steel and general structural steel having 1-5 mm thickness are usually used. Meanwhile, a lightweight and insulating shielding plate 42 is preferably provided to separate the tip of the cathode 3 furnished with the cover 40 and the region around the base end of the cathode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum vapor deposition method, and in particular, a vapor deposition base material, a metal body as an anode, and a long evaporative metal body as a cathode are arranged in a vacuum container. Then, a DC voltage is applied to the anode and the cathode to perform arc discharge, and a metal is evaporated from the cathode to form a metal vapor deposition film on the surface of the substrate to be vapor deposited. The present invention also relates to a vacuum vapor deposition method using an evaporative metal body made of a low melting point metal, which prevents deformation or melting of the cathode tip portion and enables efficient vapor deposition for a long time by stable arc discharge.

[0002]

2. Description of the Related Art Conventionally, as a method for forming a metal coating on a synthetic fiber sheet such as a woven or non-woven fabric of synthetic fibers, a chemical plating (commonly called electroless plating) method is generally employed. In this case, a synthetic fiber sheet made of a woven or non-woven fabric of synthetic fibers is supplied to the electroless plating step as a wound continuous sheet, and a metal coating is mainly formed on both sides of the sheet at the same time. Before the electroless plating step, usually, a step of subjecting the synthetic fiber continuous sheet to an alkaline degreasing treatment, a neutralizing treatment, and a catalyzing treatment is provided in advance.

The electroless plating bath is composed of metal ions to be plated, a reducing agent for the metal ions and other auxiliaries, but the metal ion concentration is lowered during the plating operation, so that it is necessary to replenish it. And control the bath composition,
Bath temperature control is important. However, if replenishment is repeatedly used after the bath is built, the bath composition will be out of balance, and therefore it is necessary to discard the plating bath at a certain point and rebuild the bath. For this reason, waste liquid treatment costs are required.
There are drawbacks such as not being preferable in terms of safety and health.

Moreover, it is technically difficult to obtain a high-purity metal film by the method of forming a metal film by electroless plating.

The present applicant has solved the above-mentioned conventional problems,
A film such as a metal film can be easily and efficiently formed on the surface of a synthetic fiber sheet as a film with good adhesion and uniform and high purity without causing pollution and safety and health problems. As a method for forming a film on a synthetic fiber sheet, a metal body is placed as an anode and a vaporizable metal body is placed as a cathode in a vacuum vessel, and a DC voltage is applied to the anode and the cathode to perform arc discharge. Due to
A method for forming a film of evaporated metal on the surface of the synthetic fiber sheet was proposed, and a patent application was previously filed (Japanese Patent Application No.
195397. Hereinafter referred to as "first application". ).

FIG. 3 is a system diagram showing a low temperature arc vapor deposition apparatus used in the method of this prior application. In this device,
An anode 2 made of, for example, a carbon steel rod is arranged in the upper portion of the vacuum container 1, and a cathode 3 made of a round rod of an evaporative metal body is arranged in the lower portion. The anode 2 is configured to mechanically move in the vertical direction and repeatedly come into contact with and separate from the cathode 3.

An object to be coated 4 is arranged in parallel with the cathode 3 in the vacuum container 1. The anode 2 and the cathode 3 are connected to a power supply device 13 via conductive wires 21 and 22, respectively, and the power supply device 13 is configured to apply a predetermined voltage according to an instruction from a control panel 14.

The vacuum container 1 is connected to the oil diffusion pump 8 via a main valve 10 and a baffle 9 by a pipe 23. The vacuum container 1 in the pipe 23 and the main valve 9A are connected to each other.
A pipe 24 including a vent valve 7 and a roughing valve 6 is connected to the oil rotary pump 5. Oil rotary pump 5 of this pipe 24
The rough suction valve 6 is connected to the suction port of the oil diffusion pump 8 by a pipe 25 including the upstream valve 11.

Reference numeral 12 is a refrigerator for cooling and recovering the evaporated oil for recirculation, which is connected to the baffle 9 by a pipe 26. Reference numeral 15 is a gas cylinder of oxygen, nitrogen or lower hydrocarbon gas, which is connected to the vacuum container 1 by a pipe 27 equipped with a valve 16, a flow meter 17, and a pressure reducing control valve 18.

In order to form a metal vapor deposition film on the object 4 to be coated by the low temperature arc vapor deposition apparatus thus constructed, first, the oil rotary pump 5 is operated to roughly pull the inside of the vacuum vessel 1 and then the oil is evaporated. The diffusion pump 8 is operated to bring the inside of the vacuum container 1 to a predetermined vacuum degree (10 ⁻³ to 10 ⁻⁵ Torr). Then, a DC voltage is applied between the anode 2 and the cathode 3 to perform arc discharge and vapor deposition of metal. In the figure, 30 is an anode driving unit, and 31 is a cathode holding unit.

In the method of the above-mentioned prior application, a round bar made of an evaporative metal is used for the cathode, and metal vapor is blown radially from the entire circumference of the round bar electrode to perform vapor deposition on the object to be coated. As compared with the case of using the plate electrode, there is an advantage that the low temperature vapor deposition is possible with high productivity.

[0012]

In the method of the above-mentioned prior application, lead (Pb: melting point 328 ° C.) is used as the cathode.
When an evaporative metal body made of a low melting point metal such as the above is used, the following problems occur.

That is, the tip of the cathode is processed into a hemispherical shape or a truncated cone shape so that the arc can be easily transferred from the anode. By repeatedly contacting the tip with the anode, the cathode material is changed. Since it is soft and has a low melting point, the tip of the cathode is deformed or melted. In a remarkable case, the length of the cathode is shortened by about 10 cm, which exceeds the contact control range with the anode, and the arc running cannot be continued.

The present invention solves the above-mentioned problems of the prior application, and arranges a vapor deposition base material, a metal body as an anode, and a long evaporative metal body as a cathode in a vacuum container, A DC voltage is applied to the anode and the cathode to perform arc discharge,
A method of forming a metal vapor deposition film on the surface of the substrate to be vapor-deposited by evaporating a metal from a cathode, comprising a cathode vapor deposition method using an evaporative metal body made of a low melting point metal as a cathode. It is an object of the present invention to provide a vacuum vapor deposition method for preventing the deformation or melting of the above and performing efficient vapor deposition for a long period of time by stable arc discharge.

[0015]

According to a first aspect of the present invention, there is provided a vacuum vapor deposition method in which a vapor-deposited substrate is placed in a vacuum container, and a metal body as an anode and a long evaporative metal body as a cathode are provided. The tips of the electrodes are arranged to face each other, a DC voltage is applied to the anode and the cathode to perform arc discharge, and the metal is evaporated from the cathode, whereby a metal vapor deposition film is formed on the surface of the deposition target substrate. A vacuum evaporation method using an evaporative metal body made of a low-melting point metal as the cathode, a cover made of a metal having a higher melting point than the low-melting point metal is attached to the tip of the cathode. And arc discharge is performed.

According to a second aspect of the present invention, in the vacuum vapor deposition method according to the first aspect, a shield is provided so as to partition a cathode peripheral region of a cathode tip end portion having the cover mounted thereon and a cathode peripheral region on a base end side of the tip end portion. It is characterized by having a plate.

[0017]

The tip of the low melting point metal cathode has a higher melting point than the low melting point metal (hereinafter referred to as "high melting point metal").
The cover constituted by is effectively protected and prevents deformation or melting. Therefore, stable arc discharge can be performed over a long period of time, and efficient vapor deposition can be performed.

According to the second aspect, even if the metal vapor is scattered from the refractory metal cover during the arc discharge, the shielding plate prevents the metal vapor from adhering to the surface of the substrate to be vapor-deposited. It is possible to form a high-quality metal vapor deposition film having high purity without being mixed.

[0019]

Embodiments of the vacuum vapor deposition method of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a schematic structure of a main part of a low temperature arc vapor deposition apparatus suitable for carrying out the vacuum vapor deposition method of the present invention. In FIG. 1, a member having the same function as the member shown in FIG. Are given the same reference numerals.

In the method of this embodiment, a refractory metal cover 40 is attached to the tip of the round bar cathode 3 having a hemispherical tip. As shown in FIG. 2A, the cover 40 has a hollow hemispherical shape with an open bottom, following the hemispherical shape of the tip portion of the round bar cathode 3.

In the present invention, the high melting point metal forming such a cover may be any high melting point material capable of sufficiently protecting the low melting point metal of the cathode, and is not particularly limited.
Iron (melting point approx. 1530 ℃), stainless alloy (melting point approx. 15
(00 ° C.) and the like are generally used. In particular, since it is easy to process, inexpensive, and has a high melting point,
For example, SS400 (melting point about 1500 ° C.) or the like is effective.

Further, it is preferable that the shape of the cover is a shape following the shape of the tip of the cathode, as shown in FIG.
Therefore, depending on the shape of the tip of the cathode, for example, as shown in FIG.
Alternatively, the cover 41 may have a hollow truncated cone shape with an open bottom as shown in FIG.

Such a cover has an inner diameter (see FIG. 2).
It is sufficient that (D) of (a) is substantially equal to or slightly larger than the outer diameter of the cathode (d of FIG. 1), and its thickness (FIG. 2).
It is preferable that t) in (a) is about 1 to 5 mm. If the wall thickness is less than 1 mm, a sufficient protective effect by the cover cannot be obtained, and if it exceeds 5 mm, there is no difference in the protective effect and the cover becomes unnecessarily bulky, which is not preferable.

The height of the cover (H in FIG. 2A)
Varies depending on the size of the cathode, the arc discharge conditions, and the material of the cathode, but in the normal case, it is preferably about 30 to 50 mm. If this height is less than 30 mm, a sufficient protective effect cannot be obtained, and if it exceeds 50 mm, the effective deposition area of the cathode is reduced, which is not preferable.

By the way, when such a refractory metal cover 40 is attached to the tip portion of the cathode 3 to perform arc discharge, evaporated particles of refractory metal are scattered from the cover 40 and adhere to the object 4 to be coated. Then, there is a possibility that the purity of the deposited film formed may be reduced.

In the present embodiment, in order to solve such a problem, a cathode surrounding area A at the tip of the cathode 3 having the cover 40 mounted thereon and a cathode surrounding area B at the base end side of the tip are provided. A disk-shaped shield plate 42 having an opening 42A at the center is provided immediately below the cover 40 so as to be partitioned.
Even if the evaporation particles of the high melting point metal are scattered from the cover 40 by the shielding plate 42, this will cause the evaporation of the refractory metal particles 4
It is possible to prevent reaching A, and to form a high-purity vapor-deposited film made of a low-melting point metal forming the cathode 3 on the surface 4A to be coated of the object 4 to be coated.

As a material for forming the shielding plate, a lightweight and insulating material is preferable, and for example, FRP, alumina and the like are preferable. In general, this shield plate has a disk shape having an outer diameter of about 5 to 10 mm smaller than the inner diameter of the object to be coated, in which an opening having a diameter of about 5 to 10 mm larger than the outer diameter of the cathode is formed. It is preferable that such a shielding plate be provided at a position separated by 5 to 10 mm from the base end portion of the cover.

According to the present invention as described above, a metal vapor deposition film can be formed on the surface 4A to be coated of the object 4 to be coated in the same manner as the method of the above-mentioned prior application. Deformation or melting of the tip of the cathode 3 can be prevented, stable arc discharge can be performed for a long time, and efficient vapor deposition can be performed.

The low melting point metals to which the present invention is applied include those having a melting point of 500 ° C. or lower, such as lead (melting point 328 ° C.), tin (melting point 231 ° C.), indium (melting point 156 ° C.), Examples thereof include metals such as zinc (melting point 419 ° C.) and low melting point alloys containing them. According to the present invention, even when a cathode made of such a low melting point metal is used, the cathode itself reaches its melting point. It is possible to continue the arc until just before.

By using a water-cooled structure for the cathode,
The duration of the arc can be further extended.

On the other hand, in the present invention, as the anode, in addition to carbon steel, stainless steel, molybdenum metal or the like can be used. When vapor-depositing a metal oxide, a metal nitride, or a metal carbide of a vapor low-melting-point metal that constitutes the cathode, in FIG. 3, oxygen gas, nitrogen gas, or a lower gas such as acetylene or methane is supplied from the gas cylinder 15 in FIG. The hydrocarbon gas may be introduced into the vacuum vessel 1 after adjusting the vacuum degree to about 10 ⁻⁴ Torr via the pressure reducing control valve 18 and the flow meter 17. In this case, the vapor deposition film of the mixture of the metal compound and the metal can be formed by adjusting the amount of introduced gas. Further, by forming a metal vapor deposition film without introducing a gas and then introducing a gas to form a vapor deposition film of a metal compound, a two-layer composite vapor deposition film can be continuously formed.

In the vacuum vapor deposition method of the present invention as described above, various low melting point metals or alloys are used for the purpose of improving various properties such as seizure resistance, lubricity and sealability on the inner surface of oil well pipe threaded joint pipes and the like. It is effective in various application fields such as when forming a functional coating film.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

Example 1 Vacuum evaporation was carried out by the apparatus shown in FIG. The specifications and working current of each member are as follows.

Object to be coated: inner diameter 90 mm, length 200 mm
SUS304 pipe cathode: diameter 30mm, length 300mm lead (purity 99.9%
Round rod cathode cover: S with an outer diameter of 36 mm, a height of 50 mm, and a wall thickness of 5 mm
Cover made of S400 Shielding plate: Opening diameter 36 mm, outer diameter 300 mm, thickness 3 mm
As a result, it was possible to form a high-purity Pb vapor-deposited film having a vapor-deposited film thickness of 40 microns by maintaining the arc for 5 minutes.

Comparative Example 1 A vapor-deposited film was formed in the same manner as in Example 1 except that the cover and the shielding plate at the tip of the cathode were not provided, and the arc was generated by the deformation or melting of the cathode in about 1 minute. It became impossible to maintain.

As is clear from the above results, according to the present invention, in the vacuum vapor deposition method using the low melting point metal cathode, the arc running is continued for a time as long as 5 times longer than the conventional one, and the short time is sufficient. It is possible to form a vapor deposition film having various thicknesses.

[0039]

As described above in detail, according to the vacuum vapor deposition method of the present invention, in the vacuum vapor deposition method using the low melting point metal cathode, stable arc discharge is performed for a long time to achieve efficient vapor deposition. You can do it.

In particular, according to the method of the second aspect, it is possible to form a high-quality metal vapor deposition film having a high purity and containing no impurities.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of a main part of a low temperature arc vapor deposition apparatus suitable for implementing the present invention.

FIG. 2 is a perspective view showing an embodiment of a cover used in the present invention.

FIG. 3 is a system diagram showing an outline of a low temperature arc vapor deposition apparatus used in the prior application.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Anode 3 Cathode 4 Object to be coated 13 Power supply device 14 Control panel 40, 41 Cover 42 Shielding plate

Claims (2)

[Claims] 1. A substrate to be vapor-deposited is placed in a vacuum container, and a metal body as an anode and a long evaporative metal body as a cathode are placed with their tips facing each other. A method of forming a metal vapor deposition film on the surface of the substrate to be vapor-deposited by applying a DC voltage to the cathode and performing arc discharge to evaporate the metal from the cathode, wherein the cathode has a low melting point. A vacuum vapor deposition method using an evaporative metal body made of a metal, characterized in that a cover made of a metal having a melting point higher than that of the low melting point metal is attached to the tip of the cathode to perform arc discharge. Law. 2. The method according to claim 1, wherein a shield plate is provided so as to separate the cathode surrounding area of the cathode tip portion where the cover is mounted from the cathode surrounding area on the base end side of the tip portion. And vacuum deposition method.