JPS60197876A - Vacuum deposition device - Google Patents

Abstract

PURPOSE:To improve the yield of the metal to be deposited by evaporation and the working efficiency of an installation with a device for plating continuously a metal by vacuum deposition onto a steel hoop by suppressing the reevaporation of the metal subjected to the vacuum deposition. CONSTITUTION:A steel hoop 1 is conducted via a vacuum sealing device 31, etc. to a vacuum vessel 2 in which a low pressure is maintained. The evaporating metal, for example, Zn vapor 5, from an evaporation vessel 4 is plated by vapor deposition on said hoop in the stage when the hoop is guided by a roll 3. The hoop is again conducted via a high pressure sealing device 6, etc. to the high pressure side. The vapor 5 everges off the roll 3. Inner ducts 12 heated by heaters are provided to the arc-shaped covers 10, 11 provided in the inlet of the roll 3 and are connected to the sealing bar 13 of the device 6. The Zn 8 evaporating again from the hoop 1 is thus suspended in the ducts 12 without vapor deposition. The reevaporation is eliminated when the partial pressure of the Zn vapor attains the satd. vapor pressure P1 at the reevaporation temp. of the solid Zn in the hoop 1. The reevaporation is kept suppressed even if a large amt. of the plated hoop 1 passes through the inside of the ducts 12 after the attainment of the pressure P1 and therefore the yield of Zn is improved and the working efficiency of the installation is improved as well.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a vacuum evaporation apparatus for continuously vacuum evaporating metal such as zinc onto a steel strip.

[Conventional vacuum evaporation equipment and its drawbacks]

When continuously depositing a metal such as zinc on a steel strip, 7
The pressure is gradually introduced from 60 Torr to the deposition chamber through a vacuum sealing device. For example, when depositing zinc, the pressure in the deposition chamber is 1TO.
rr~α0001 Torr. After vapor deposition, the strip is introduced into the atmosphere at a pressure of 60 Torr via a sealing device. In this case, the metal deposited on the steel strip, such as zinc, reevaporates while passing through the deposition chamber and the low-pressure sealing device, and adheres to the deposition chamber and the sealing device. When depositing for a long time,
A large amount of re-evaporated metal, such as zinc, accumulates in the deposition chamber and sealing equipment, resulting in a reduction in the operating rate of the equipment, such as shutting down the sealing equipment or shutting down the entire equipment to remove the adhered zinc. It has some drawbacks. Further, the re-evaporated zinc is wasted and there is a large loss.

Due to the above circumstances, it is necessary to eliminate re-evaporated zinc, improve the zinc yield, and at the same time increase the operating rate of equipment and reduce plating costs.

[Object of the present invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vacuum evaporation apparatus that eliminates the drawbacks of the conventional apparatus described above. That is, the present invention provides a vacuum evaporation apparatus that can improve the yield of vacuum-deposited metals such as zinc by suppressing the re-evaporation of the metals, and at the same time improve the operating rate of the equipment. The purpose is to

[Configuration of the present invention]

As a means for achieving the above object, the present invention has the following features:
The heating duct is placed in a chamber maintained at a vacuum pressure that virtually prevents re-evaporation immediately after plating. That is, the present invention provides, in a vacuum evaporation apparatus that continuously applies vacuum evaporation plating of a metal such as zinc to a steel strip, between the time immediately after plating and the chamber maintained at a vacuum pressure where re-evaporation does not actually occur. This vacuum evaporation apparatus is characterized in that a heating duct heated to a temperature higher than the temperature of the steel strip is disposed so as to surround the steel strip.

Specifically, the present invention provides an inner duct that surrounds the steel strip from the outlet of the vacuum evaporation device to the sealing device and between the low-pressure side sealing device, and by heating this duct, reevaporated zinc is transferred to the sealing device. At the same time, it is necessary to heat the inch duct to a temperature that is the same as or slightly higher than the re-evaporation temperature of the zinc deposited on the steel strip. This is to maintain the pressure as much as possible and to reduce the leakage of zinc vapor from the inch duct. In this way, the present invention can suppress the continuous re-evaporation of zinc, that is, almost eliminate re-evaporation, improving the operating rate of equipment and the yield of zinc. It is something that can be done.

Hereinafter, the present invention will be explained in detail based on Figure 1. 1st
The figure shows a vacuum evaporation apparatus that is an embodiment of the present invention. In FIG. 1, the steel strip 1 is connected to a vacuum sealing device 51 on the entry side.
．． 3434 to the low pressure vacuum chamber 2, and the roll 3
In the process of being guided to the evaporator 4, metal vapor such as zinc vapor 5 evaporated from the evaporation tank 4 is deposited and plated, and is again guided to the high pressure side to each vacuum sealing device via 29 and 30.

The solid zinc deposited on the steel strip 1 starts to evaporate again under vacuum pressure where the atmospheric pressure is low. This phenomenon is called reevaporation. The re-evaporation rate decreases as the atmospheric pressure increases, but vacuum pressures of 10 to 20 Torr may cause equipment problems. Particularly on the low pressure side, the amount of re-evaporation is large.

The solid zinc continues to reevaporate until it reaches the saturated vapor pressure of the temperature of the zinc deposited on the steel strip 1. Steel strip 1 after vapor deposition
If the equipment through which the zinc passes, for example, the vacuum sealing equipment 6, 29, 50 on the outlet side of the vacuum chamber 2, and the intermediate duct 7 connecting each sealing equipment are at room temperature, the re-evaporated zinc 8 will pass through each of the aforementioned equipment. Deposit. That is, zinc is continuously reevaporated from the vapor-plated surface of the steel strip 1 to the device and deposited on the device. Deposited zinc must be removed periodically,
Hinder productivity.

The zinc vapor 5 guided through the channel 9 is deposited on the steel strip 1 in the process of being guided by the roll 3, and the vapor deposited zinc plating is completed and the zinc vapor 5 leaves the roll 3 and comes out. An inner duct 12 heated by a heater is provided on the arcuate covers 10 and 11 at the outlet of the roll 3, and the outer bar 1 of the vacuum sealing device 6 is provided with an inner duct 12 heated by a heater.
Connect to 3. By surrounding the zinc-deposited steel strip 1 with the heated inner duct 12, the zinc re-evaporated from the steel strip 1 cannot be deposited on the inner duct 12, and exists floating in the inch duct 12 as re-evaporated zinc 8. , the partial pressure of zinc vapor is the saturated vapor pressure P at the reevaporation temperature T of solid zinc in the strip steel 1
, the re-evaporation phenomenon disappears. After reaching the saturated vapor pressure, re-evaporation remains suppressed even if a large amount of the vacuum-deposited steel strip 1 passes continuously through the inner duct 12, so the yield of zinc is greatly increased. improves. Furthermore, since the re-evaporation of zinc 8 is suppressed, the operating rate of the entire equipment is increased and the productivity is also greatly improved.

To explain in more detail the structure of the apparatus according to the embodiment of the present invention shown in FIG. 1, the evaporation tank 4 is heated by a heater 15 to melt zinc. The molten zinc 14 heated and melted to 430° C. to 580 tl is heated to evacuate the atmospheric gas, such as nitrogen gas, from the vacuum chamber 2 with the vacuum pump 21 until the atmospheric pressure in the vacuum chamber reaches 1 to 580 tl.
When the temperature reaches 0.0001 Torr, the zinc vapor 5 starts to evaporate and is guided into the channel 9 which is a guide hood heated by the heater 16.
is continuously deposited. A heater 19 is installed inside the roll 3.
is provided, and the surface temperature of the cylindrical surface of the four-wheel 3 and the disks (not shown) at both ends of the cylinder is a temperature higher than the re-evaporation temperature of the zinc vapor 5 under the vapor pressure of the zinc vapor 5, for example 1'
It is heated to 580°C at RORR and 250°C at α0001 Torr.

In order to prevent the zinc vapor 5 guided into the channel 9 from leaking into the vacuum chamber 2 in large quantities, an arcuate cover 25 is provided on the entrance side of the steel strip 1 of the roll 3 and heated with a heater 17.
A cover 10 is provided on the exit side of the roll 3 of the steel strip 1, and by heating with a heater 17, the surfaces of the covers 25 and 10 facing the steel strip 1 are heated to the re-evaporation temperature of the zinc vapor 5 under the vapor pressure of the zinc vapor 5. or above, e.g. I Torr to l 00
Heat to 250°C to 580°C at 0.01 Torr. In this way, the structure is such that zinc is not deposited on the roll 3 and the arcuate covers 25 and 10.

The gap 26 between the roll 3 and the arcuate covers 25 and 10 is set as small as possible so that the steel strip 1 does not come into contact with the covers 25 and 10, and the length of the gap 26 in the circumferential direction of the roll 30 is set as small as possible within the range that the steel strip 1 does not come into contact with the covers 25 and 10. It is designed to be as long as possible, and to prevent the zinc vapor 5 from causing a pressure loss while passing through the gap 26 and causing pressure loss to the vacuum chamber 2 and the inner duct 12 as much as possible.

In addition, an arcuate cover 1 is provided on the opposite side of the roll 3 from where the strip passes through.
1 is provided and the heater 18 is used to heat the zinc vapor 5 to a temperature higher than the re-evaporation temperature of the cover 11 to prevent the zinc vapor 5 from being deposited on the inner surface of the cover 11.

The gap 27 created by the cover 11 and the roll 5 is set as small as possible without contacting each other, and the re-evaporated zinc 8 in the inner duct 12 comes out into the vacuum chamber 2 with a pressure loss in the gap 27. It has a structure that suppresses this.

One end of the inner duct 12 is connected to the covers 10 and 11, and the other end is connected to the sealer 15 of the vacuum sealing device 6, leaving an expansion margin, and is heated by a heater 20.

The vacuum seal devices 6 and 34 are evacuated by the vacuum pump 22, the vacuum seal devices 29 and 53 are evacuated by the vacuum pump 26, and the vacuum seal devices 50 and 31 are evacuated by the vacuum pump 24. pressure)
When the pressure is lowered in the process of passing through each vacuum sealing device and zinc is evaporated in vacuum chamber 2, I Torr ~ (L
0001 Torr, and the pressure gradually increases in the process of passing through each vacuum sealing device at the deposition edge p, 760 Torr.
After that, the vacuum evaporation plating work is completed.

The sealing roll 28 of the vacuum sealing device 6.29.50 is
A heater (
(not shown) is provided and heated to a temperature equal to or higher than the re-evaporation temperature of the zinc deposited on the steel strip 1. A heater (not shown) is also installed in the sealer 13.
is provided and heated to the same temperature as the seal roll 28 to prevent re-vaporized zinc 8 from adhering.

To explain the operation of the vacuum evaporation device, when the zinc vapor 5 is deposited on the steel strip 1 and the steel strip 1 comes out from the roll 3 and passes through the inner duct 12 heated by the heater 20,
Re-evaporation occurs from the zinc surface of the steel strip 1. Inside the inner duct 12, steal gas (N) and reevaporated zinc 8 coexist. Reevaporation continues from the zinc surface of the steel strip 1 until the zinc vapor partial pressure of the reevaporated zinc 8 reaches the saturated vapor pressure P1 of zinc corresponding to the reevaporation temperature TI of zinc in the steel strip 1.

In this case, if the temperature of the surface (inner surface) of the inner duct 12 heated by the heater 20 through which the steel strip 1 passes is equal to or higher than the re-evaporation temperature T1 of zinc in the steel strip 1, Reevaporated zinc 8 will not adhere to the inner surface of the inner duct 12.

When the steel strip 1 passes through the vacuum chamber and the vacuum sealing device 29 and 50, a continuous vacuum-deposited steel strip without zinc adhesion can be smoothly produced.

On the other hand, after the zinc vapor partial pressure of the reevaporated zinc 8 reaches the saturated vapor pressure of zinc corresponding to the reevaporation temperature TI of zinc in the strip steel 1 in the inner duct 12, reevaporation no longer occurs.
The amount of ineffective zinc vapor lost through re-evaporation will be greatly reduced.

Similarly to the inner duct 12, inner ducts 32 and 32' are provided between the vacuum sealing devices 6 and 29 under low pressure and between the vacuum sealing devices 29 and 30, leaving an expansion allowance, and are heated by the heater 20. This is to suppress re-evaporation.

The vacuum pressure required to suppress re-evaporation is approximately 20 Torr.
However, it is necessary to provide an inner duct between the vacuum chamber 2 and the vacuum sealing device of about 20 Torr, and to heat it with a heater. The inner duct itself is made of a thin plate of stainless steel or ordinary steel, and the outer surface of the inner duct is insulated with a heat insulating material (not shown), so it can be heated with a small amount of electric power.

Note that if the total pressure of the nitrogen gas (N2) and re-evaporated zinc vapor 8 in the inner duct 12 is not equal to the atmospheric pressure in the vacuum tank 2, the molten zinc 14 in the evaporation tank 4 will evaporate,
Since vacuum deposition is no longer carried out on the steel strip 1, small holes (not shown) are provided in the inch ducts 12.32 and 32', so that the atmospheric pressure in the respective vacuum chamber and the inner duct 12, 52.52' are Of course, the total pressures of the N, gas and vapor of the revaporized zinc 8 are made equal.

In this case, the amount of vapor of the reevaporated zinc 8 that diffuses to the outside from the hole provided in the inner duct is negligible.

The present invention has been described in detail above, and the present invention will be further explained in more detail by giving an example using the apparatus shown in FIG. 1, which is an embodiment of the present invention.

[Example] Using the apparatus shown in FIG. 1, plating work was carried out under the following conditions.

Band steel 0.6 m thickness X! +00WrM width ordinary steel strip speed 15 g/min Steel strip temperature before vapor deposition 250℃ Vacuum pressure/vacuum chamber pressure α07 Torr Pressure of fist vacuum sealing device 6 1. OTorr/vacuum seal device 29 pressure 10 Torr/vacuum seal device 30 pressure 70 TOrr/inner duct 12,
52. and 32' inner wall temperature 300C, molten zinc 14
Temperature: 4.80°C Inner wall temperature of arcuate cover 1, 11 and 25: 480°C
External temperature of roll 3: 480°C ・Surface temperature of sealing roll 28 and sealer 13: 30
0°C plating film thickness was 40°C. As a result, no zinc adhesion due to re-evaporation was observed on the inner walls of inner ducts 12, 32 and 52'. Additionally, the amount of zinc that came out from the small holes provided in the inner ducts 12j2 and 32' was negligibly small, confirming that re-evaporation was sufficiently suppressed by heating the inch ducts 12, 52 and 32'. It was done.

[Effects of the present invention]

As explained above, the present invention suppresses the re-evaporation phenomenon of deposited zinc by providing a heated inner duct, greatly reduces the amount of zinc re-evaporated, and reduces the amount of zinc that is re-evaporated. This has the remarkable effect of improving the operating rate of the entire facility and increasing productivity without causing re-evaporated zinc to adhere as much as possible.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a vacuum evaporation apparatus according to an embodiment of the present invention. 1...Strip steel 2...Vacuum tank 3...Roll 4...Evaporation tank 5...Zinc vapor 7...Intermediate duct 8...Reevaporation zinc 9...Channel 10. ．． 11.25...Cover 12.52.
52'...Inner duct 13...Seal bar 14
... Molten zinc 15-20 ... Heater 21-24
...Vacuum pump 26.27...Gap recovery agent 1) Clearance agent Ryo Hagiwara - Continued from page 1 0 inventions Author Ken Yanagi - Hiroshima Research Institute, 4 Kannon Shinmachi, Nishi-ku, Hiroshima City 0 inventions Person Mitsuo Kato 4 Kannon Shinmachi, Nishi-ku, Hiroshima City
0 in the Hiroshima Research Institute Author Kazu 1) Tetsuyoshi 4 Kannon Shinmachi, Nishi-ku, Hiroshima City 0 in the Hiroshima Research Institute Author Norio Tsukiji 5 Ishizu Nishimachi, Sakai City @
Inventor Takuya Ai 5, Ishizu Nishimachi, Sakai City @ Inventor Toshiharu Tachibana 5, Ishizu Nishimachi, Sakai City [Phase]
Inventor: Koji Nakanishi, 5-basement, 6-2, Ishizu Nishi-cho, Sakai City, Mitsubishi Heavy Industries, Ltd., 6-2, below, Mitsubishi Heavy Industries, Ltd., 6-n, Mitsubishi Heavy Industries, Ltd., Nissin Steel, Hanshin Research Co., Ltd. Inside the office

Claims (1)

[Claims] In vacuum evaporation equipment that continuously applies vacuum evaporation plating of metals such as zinc to steel strips, the temperature of the steel strip must rise between the time immediately after plating and the room maintained at a vacuum pressure that virtually prevents re-evaporation. 1. A vacuum evaporation apparatus characterized in that a heating duct that is heated to a temperature of 100 nm is disposed so as to surround the steel strip.