JPH06136511A - Method for continuous coating pretreatment of strip and device therefor - Google Patents

Abstract

PURPOSE:To achieve the rapid and stable coating pretreatment by generating the glow discharge between a metallic strip and an anode electrode in a vacuum chamber, covering these by a closely arranged double shield, and thereby suppressing the abnormal discharge. CONSTITUTION:A metallic strip 2 is continuously traveled in a vacuum chamber 1, and the glow discharge is generated between this metallic strip and an anode electrode 7, and the continuous coating pretreatment is executed to the metallic strip 2. The anode electrode 7 and the metallic strip 2 in the treatment area are covered by the double shield consisting of an inner shield 5 and an outer shield 6 mutually approached. This inner shield 5 is set to the anode voltage or the float voltage while the outer shield 6 is set to the grounding voltage. It is preferable that the distance d3 between these shields is 1-25mm and the distance d2 between the inner shield 5 and the metallic strip 2 is 1-25mm, respectively. As for the pressures P1, P2 inside and outside the metallic shield, the glow discharge is preferably generated under the conditions of P1>P2 and P2<5X10<-3>Torr.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for subjecting a metal strip plate such as a continuously running steel plate to coating pretreatment by bombardment.

[0002]

2. Description of the Related Art Generally, water and hydrocarbons are adsorbed (physical adsorption) and oxide films are adsorbed (chemical adsorption) on the surface of a metal strip. If it is applied, the adhesion between the strip plate and the coating material deteriorates due to the adsorption of these. For this reason, when coating the strip by vacuum deposition, ion plating, sputtering or the like in a vacuum atmosphere, it is necessary to perform a bombardment treatment (pretreatment) on the strip immediately before coating.

The bombardment process is performed by using, for example, DC glow discharge. In this case, a metal strip plate is used as a cathode (cathode), an anode electrode (anode) is installed on the treated surface side, and a voltage of 500 to 2000 V is applied between the two to apply D.
C. Perform bombardment treatment by glow discharge.

However, for example, when performing a vacuum vapor deposition process, it is desirable that the metal strip be at the ground potential because of the equipment cost, and in the ion plating process, from the viewpoint of maintaining a good film quality, the number of metal strips to be changed to several. A negative potential of 10 to several hundred volts is applied. As a result, the potential of the anode electrode for bombardment becomes a positive potential of about several hundred to 2000 V with respect to the ground potential.

On the other hand, in the pretreatment chamber, there are many parts including the chamber itself, which are held at the ground potential,
Since these also have a negative potential relative to the anode electrode, there is a problem that abnormal discharge occurs everywhere in the chamber.

As a countermeasure for such a problem, the inventors of the present application have previously extended the shield of the anode electrode to the vicinity of the metal strip plate, as described in Japanese Patent Laid-Open No. 4-198466, and further, It is proposed to cover the anode and the metal strip with such a shield.

However, although the abnormal discharge is suppressed to some extent by this method, when the DC glow discharge current is increased, the abnormal discharge occurs between the shield and the chamber, so that the high speed and stable bombarding process is performed. Therefore, it is still not enough.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to suppress abnormal discharge in the pretreatment and achieve high-speed and stable coating pretreatment (bone birdment treatment). It is an object of the present invention to provide a continuous coating pretreatment method and apparatus capable of producing a strip.

[0009]

According to the present invention, firstly, a metal strip is continuously run in a vacuum chamber, and a glow discharge is generated between the anode electrode and the metal strip in the vacuum chamber. A method for continuous coating pretreatment of a metal strip, which comprises continuously applying a coating pretreatment to a metal strip, wherein an inner shield is provided in which an anode electrode and a metal strip in a treatment region are provided close to each other. And a double metal shield consisting of an outer shield, and of these, the inner shield is set to an anode potential or a float potential,
There is provided a continuous coating pretreatment method for a strip, which comprises causing an outer shield to have a ground potential to generate a glow discharge.

Secondly, a vacuum chamber, means for continuously running a metal strip in the vacuum chamber, an anode electrode provided in the vacuum chamber, and between the anode electrode and the metal strip. A means for generating a glow discharge and a double metal shield consisting of an inner shield and an outer shield provided close to each other and covering the anode electrode and the metal strip in the treatment area are provided, the inner shield being the anode. A continuous coating pretreatment device for strips is provided, characterized in that it is held at a potential or a frost potential and the outer shield is held at a ground potential. In this case, the distance between the inner shield and the outer shield and / or the distance between the inner shield and the metal strip is 1 mm or more, 25
It is preferable that the thickness is less than or equal to mm.

Furthermore, thirdly, a metal strip is continuously run in the vacuum chamber, and glow discharge is generated between the anode electrode and the metal strip in the chamber so that the metal strip is continuous with the metal strip. A continuous coating pretreatment method for a metal strip to be subjected to coating pretreatment, in which the anode electrode and the metal strip in the treatment area are covered with a metal shield, the pressure inside the metal shield is P ₁ , and the pressure outside is the when the P _2, to provide a continuous coating pretreatment method of the strip, characterized in that to produce a glow discharge is set to P _1> P ₂ and P ₂ <5 × 10 ^-3 Torr conditions .

[0012]

In the first and second aspects of the present invention, the anode electrode and the metal strip are covered with a double metal shield, and the inner shield of these double metal shields is set to the anode potential or Glow discharge is generated with the float potential and the outer shield as the ground potential. In this case, the potential of the floating material in contact with the discharge plasma is
Since it is almost equal to the anode potential, the inner shield potential is eventually held at the anode potential, and the discharge space is surrounded by the inner shield of the anode potential. Therefore, since the cathode existing in the discharge space is only the metal strip, a stable glow discharge is formed between the anode electrode and the inner shield and the metal strip. In this case, since the inner shield is almost at the anode potential, if there is no outer chamber, abnormal discharge may occur between the inner shield and the chamber at earth potential. Since it is provided, the abnormal discharge can be suppressed based on Paschen's law. In this case, considering the range where discharge does not occur at a normal power supply voltage based on Paschen's law and the aspect of space saving, between the inner shield and the outer shield and / or between the inner shield and the metal strip. The distance between them is preferably 1 mm or more and 25 mm or less.

In the third aspect of the present invention,
When the anode electrode and the metal strip are covered with a metal shield, and the pressure inside the metal shield is P ₁ and the pressure outside is P ₂ , P ₁ > P ₂ , so discharge plasma escapes from the shield. Since it is suppressed to spread over the entire chamber and P ₂ <5 × 10 ^-3 Torr, 1000V
It does not discharge at a moderate voltage. Therefore, also in this mode, abnormal discharge is suppressed.

[0014]

Embodiments of the present invention will be described below.
1 is a side sectional view showing an example of a continuous pretreatment apparatus for carrying out the present invention, and FIG. 2 is a sectional view taken along the line AA '. This continuous pretreatment apparatus has a vacuum chamber 1 in which a metal strip 2 travels by traveling means (not shown), and the inside of the vacuum chamber 1 is exhausted by a vacuum pump 11 connected to the upper portion thereof.

An anode electrode 7 is disposed near the bottom of the vacuum chamber 1 so as to face the metal strip 2 running in the vacuum chamber 1. A gas flow hole 12 is formed in the anode electrode 7, and an argon gas is supplied between the metal strip 2 and the electrode 7 from a gas supply source (not shown) through the gas flow hole 12.

The metal strip 2 and the anode electrode 7 are connected to a power source 9 via a wiring 8. The power source 9 is connected to the metal strip 2 via a conductor roll 10, and the power source 9 causes the anode electrode 7 and For example, between the metal strip 2 and 50
A voltage of 0 to 2000 V is applied. When the coating is performed by, for example, vacuum deposition, it is desirable and common for the equipment that the metal strip 2 be at the ground potential. Therefore, the anode electrode 7 is -500 to -2000.
It has a potential of V.

By thus applying a voltage between the metal strip 2 and the anode electrode 7, a glow discharge is generated between them in the presence of argon gas, and the argon ions generated by this glow discharge cause Metal strip 2
A bombardment process is applied to the processed surface 2a.

The anode 7 and the metal strip 2 in the bombardment treatment area are surrounded by an inner shield 5 and an outer shield 6. These are provided close to each other, are insulated from each other by the seal insulator 4a, and are insulated from the anode electrode 7 by the insulator 4b. The outer shield 6 is held at the ground potential by being grounded, and the inner shield is not connected anywhere and is held at the floating potential.
The floating potential of the inner shield is
This is because the inner shield is made substantially equal to the anode electrode potential when discharge plasma is formed between the metal strip and the anode electrode, and may be appropriately connected or a separate power source may be provided to attain the anode potential. Reference numeral 3 is a seal member for sealing the vacuum chamber 1 and the traveling metal strip plate 2.

In order to perform the coating pretreatment by the pretreatment apparatus constructed as above, first, the vacuum chamber 1 is evacuated, and the vacuum chamber 1 is evacuated through the gas flow holes 12.
Argon gas is introduced into the chamber, and the chamber 2 is set to 1 to 5 x 1
Held at about 0 ^-5 Torr. Next, a voltage of 500 to 2000 V is applied between the metal strip 2 and the anode electrode 7 which are supplied to the vacuum chamber 1 through the heating process which is the previous process,
Glow discharge is generated between the metal strip 2 and the anode electrode 7. As a result, the ionized argon gas collides with the processing surface 2a of the strip plate 2 and the impurities on the surface and the bulk itself are sputtered and activated, and the bombardment processing is performed. At this time, the distance d ₁ between the electrode 7 and the metal strip 2 is preferably about 50 to 200 mm.

In this case, the inner shield 5 having a floating potential, which surrounds the anode electrode 7 and the metal strip 2 in the bombardment treatment region, is at the anode electrode potential as described above, so that the cathode is against the discharge plasma. Therefore, it is possible to prevent abnormal discharge that has conventionally been generated by using a member at earth potential such as the chamber 1 or the vacuum pump as a cathode.

On the other hand, since the outer shield 6 is held at the ground potential and is provided close to the inner shield 5, Paschen's law suppresses the discharge between them. That is, according to Paschen's law, the discharge start voltage is inversely proportional to the distance between the electrodes, so that the discharge between the inner shield 5 and the outer shield 6 can be suppressed. In this case, when the distance between the inner shield 5 and the outer shield 6 is d ₃ mm and the pressure between the shields is P ₃ Torr, d ₃ ≦ 1 / P ₃ according to Paschen's law.

If d ₃ is made as small as possible within the range of,
No discharge occurs between the inner shield 5 and the outer shield 6 at a voltage of. Since the bombardment treatment using glow discharge is generally performed at 1 to 10 ^-2 Torr, d ₃ is in the range of 1 to 25 mm in consideration of this pressure and space saving. Is most preferable.

If the inner shield 5 and the non-treated surface 2b of the metal strip 2 are brought close to each other, the discharge on the non-treated side of the strip is suppressed, and most of the bombardment current is absorbed by the strip 2. It becomes possible to put the material on the processing surface 2a side, and the efficiency can be improved. In this case, the distance between the inner shield 5 and the non-treated surface 2b of the metal strip 2 is d ₂ mm, and the pressure between them is P ₂
If Torr, then according to Paschen's law, d ₂ ≦ 1 / P ₂

If d ₂ is made as small as possible within the range of, discharge is generated between the inner shield 5 and the non-treated surface 2b of the metal strip 2 as in the case between the inner shield 5 and the outer shield 6 described above. Since it does not occur, all of the bombardment current can be applied to the processing surface 2a side of the strip plate 2. Therefore, from the same viewpoint, it is most preferable to set d _{2 in} the range of 1 to 25 mm.

Since the abnormal discharge can be prevented as described above, the power source 9 is extremely stable, and most of the output current of the power source 9 is used for the bombardment treatment, so that the treatment efficiency is remarkable. high.

In the above example, the outer shield of the ground potential is provided close to the inner shield of the anode potential to prevent the abnormal discharge, but the abnormal discharge can be prevented from the viewpoint of pressure. That is, by using the seal insulator 4 and adjusting the exhaust of the vacuum pump 11 to lower the pressure P ₂ outside the shield below the pressure P ₁ inside the shield, the discharge plasma inside the shield shields the metal of the shield. It is possible to prevent it from coming out of the through hole of the strip plate 2 and spreading into the entire chamber 1, and further, to reduce P ₂ to P ₂ <5
With x10 ^-3 Torr, no discharge occurs outside the shield at about 1000V. Therefore, in this case, the abnormal discharge can be effectively prevented without providing the outer shield. The metal strip that has been subjected to the pre-coating treatment as described above is supplied to the coating apparatus so as to be subjected to the coating treatment in the next step.

The present invention is not limited to the above embodiment, but can be variously modified. For example, it is also possible to apply a magnetron electrode or the like as the anode electrode. Further, as the metal strip plate, various materials such as steel, aluminum, titanium and copper can be used. Further, although the argon gas is used as the atmosphere gas for forming the glow discharge, the present invention is not limited to this, and other gas such as hydrogen may be used.

[0028]

According to the present invention, there is provided a continuous coating pretreatment method and apparatus for a strip, which can suppress abnormal discharge in the pretreatment and achieve a stable and fast coating pretreatment. Further, the treatment efficiency is high, and the treatment efficiency can be improved to nearly 100% by optimizing the conditions, which eventually contributes to the reduction of the equipment cost and the improvement of the film quality in the coating in the next step. .

[Brief description of drawings]

FIG. 1 is a side sectional view showing an example of a continuous pretreatment apparatus for carrying out the present invention.

2 is a cross-sectional view taken along the line AA ′ of the apparatus of FIG.

[Explanation of symbols]

1; vacuum chamber, 2; metal strip, 5; inner shield,
6; outer shield, 7; anode electrode, 9; power supply, 1
0: Conductor roll, 12: Gas flow hole.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Kibe 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (72) Kinya Kisoda 2-chome, Kyomachibori, Nishi-ku, Osaka-shi, Osaka No. 7 Inside Chugai Furnace Industry Co., Ltd. (72) Inventor Hachiro Tonai 2-4-7 Kyomachibori, Nishi-ku, Osaka-shi, Osaka Inside Chugai Furnace Industry Co., Ltd. (72) Eiji Furuya Kyomachibori, Nishi-ku, Osaka-shi, Osaka 2-4-7 Chugai Furnace Industry Co., Ltd.

Claims (7)

[Claims] 1. A metal strip is continuously run in a vacuum chamber, and glow discharge is generated between an anode electrode and the metal strip in the vacuum chamber to continuously coat the metal strip. This is a continuous coating pretreatment method for a metal strip to be subjected to pretreatment, in which the anode electrode and the metal strip in the treatment area are covered with a double metal shield consisting of an inner shield and an outer shield provided close to each other. A pretreatment method for continuous coating of a strip, characterized in that an inner shield of these is set to an anode potential or a float potential, and an outer shield is set to a ground potential to cause glow discharge. 2. The continuous coating pretreatment method for a strip according to claim 1, wherein the distance between the inner shield and the outer shield is 1 mm or more and 25 mm or less. 3. The pretreatment method for continuous coating of a strip according to claim 2, wherein the distance between the inner shield and the metal strip is 1 mm or more and 25 mm or less. 4. A vacuum chamber, means for continuously moving a metal strip in the vacuum chamber, an anode electrode provided in the vacuum chamber, and a glow discharge between the anode electrode and the metal strip. Means and a double metal shield consisting of an inner shield and an outer shield provided close to each other and covering the anode electrode and the metal strip in the treatment region, the inner shield being the anode potential or the float potential. And the outer shield is held at ground potential. 5. The continuous coating pretreatment device for a strip according to claim 4, wherein the distance between the inner shield and the outer shield is 1 mm or more and 25 mm or less. 6. The continuous coating pretreatment apparatus for a strip according to claim 6, wherein the distance between the inner shield and the metal strip is 1 mm or more and 25 mm or less. 7. A metal strip is continuously run in a vacuum chamber, and glow discharge is generated between the anode electrode and the metal strip in the chamber to continuously coat the metal strip. A method for continuous coating pretreatment of a metal strip to be treated, wherein the anode electrode and the metal strip in the treated area are covered with a metal shield, the pressure inside the metal shield is P ₁ , and the pressure outside is P ₂ . If P ₁
> P ₂ and P ₂ <5 × 10 ⁻³ Torr A continuous coating pretreatment method for strips, characterized in that glow discharge is generated under the conditions.