JPH05214529A - Electron-beam deposition plating method - Google Patents

Abstract

PURPOSE:To improve deposition efficiency in electron-beam deposition plating by bringing the incident angle of an electron beam on the upper surface of a plating material closer to vertical when a shutter is opened than when the shutter is closed. CONSTITUTION:The upper surface of a plating material 1 in a crucible is irradiated with an electron beam from an electron gun 3 provided beside the crucible 2, and a material 6 above the crucible is deposition-plated. A shutter 5 is arranged between the plating material 1 and the material to be plated 6 to block the ascension of the plating material vapor when plating is suspended. The incident angle of the electron beam on the upper surface of the plating material 1 is brought closer to vertical when the shutter 5 is opened that when the shutter 5 is closed. A high-quality plating is obtained in this way with high efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a method for evaporating or sublimating a plating material in a crucible by irradiating an electron beam, and performing vapor deposition plating on a lower surface of a long steel plate, film or the like which continuously runs above the plating material. Regarding details, in detail,
The present invention relates to an electron beam vapor deposition plating method in which an incident angle of an electron beam is changed according to interruption, resumption, etc. to perform efficient vapor deposition plating.

[0002]

2. Description of the Related Art FIG. 2 is an explanatory view showing an example of a state in which a plating material 1 in a crucible is irradiated with an electron beam. A molten plating material 1 is loaded in the crucible 2, and an electron gun 3 is provided on a side portion of the crucible 2. Deflection coils 4a and 4b are arranged between the electron gun 3 and the crucible 2. The electron beam emitted obliquely upward from the electron gun 3 is deflected by the deflection coils 4a and 4b so as to be curved obliquely downward and is irradiated toward the upper surface 1A of the plated material 1 in the crucible 2. As shown in FIG. 3, two sets of scanning coils 33 and 34 are provided inside the electron gun 3, and the electron beam is two-dimensionally deflected in the X and Y directions, and the electron beam is placed on the upper surface of the plating material. In 1A, scanning is performed with a scanning locus as indicated by a chain line (Bk in FIG. 2).

FIG. 4 is an explanatory view showing an example of a state in which vapor deposition plating is being performed. The plating material 1 in the crucible 2 is irradiated with an electron beam, and the vapor generated by this irradiation continuously travels in the direction of arrow M. It is vapor-deposited on the lower surface of the material to be plated such as the steel strip 6. A shutter 5 which is opened and closed while turning in the direction of arrow R is provided above the crucible 2, and the shutter 5 is moved to a position 5a shown by a broken line during preheating before the start of operation or when traveling of the steel strip is interrupted. Then, the evaporated plating material is prevented from excessively adhering to the material to be plated which is waiting or stopped.

[0004]

In order to effectively vaporize the plating material vapor, it is desired that the distance h between the upper surface 1A of the plating material and the lower surface of the material 6 to be plated be narrowed. For this reason, it is difficult to arrange the electron gun 3 above the material to be plated, and it is common to arrange the electron gun 3 on the side or below. For example, as shown in FIG. An electron beam is deflected by the deflection coils 4a and 4b described above, the beam trajectory B thereof is curved, and the upper surface 1A of the plated material is irradiated with the electron beam.

On the other hand, even when the vapor deposition plating is interrupted,
Since it is necessary to heat the plated material 1 and the like, the electron beam irradiation must be continued. Of course, this is even more so when preheating. Therefore, the electron beam trajectory B is shown in FIG.
As shown in, the shutter position when closing 5a passes below the tip of
That is, it had to be set so as to reach the upper surface of the plated material 1 through a considerably low position.

On the other hand, the electron beam locus B in the steady operation in which the shutter 5 is opened and vapor deposition plating is the same as when the shutter is closed, and therefore the electron beam incident angle θ on the plated material upper surface 1A remains small. The amount of electron beams diffusely reflected on the upper surface 1A increases, and the amount of heat used for evaporation of the plating material decreases, resulting in very poor heat exchange efficiency. When the incident angle θ is small, the electron beam irradiation (projection) area on the upper surface 1A of the plated material becomes large, so that the electron beam irradiation density is low and the heat exchange efficiency for evaporation is further deteriorated. It was

By the way, when the electron beam is moved along the scanning locus Bk, the incident angle θ changes at a position close to the electron gun and a position far from the electron gun, and the upper surface of the plated material in the crucible 2 is vertically displaced (descended due to consumption). And rise due to replenishment) also changes the irradiation angle θ. At this time, in the prior art, since the incident angle θ is always small, there is a large fluctuation range caused by the above reason, and this fluctuation causes an unstable vapor generation amount, resulting in deterioration of vapor deposition plating quality.

As a means for solving the above problem, it is conceivable to change the shape of the shutter 5 and the driving means so that the electron gun 3 can be arranged at a higher position. The shutter 5 must be capable of opening and closing operation within a limited space of the vacuum deposition plating chamber, and the drive device provided on the normal pressure side and the shutter 5
Must be connected while maintaining a high vacuum. For this reason, the structure in which the shutter 5 is connected to the drive source via the swing shaft is considered to be the safest in order to secure the vacuum sealability,
Further, it has been an indispensable condition that the shutter 5 itself does not have an operating portion so that the operation failure due to the adhesion of the plating material is not caused. In consideration of such a structural restriction and vapor collecting property, the shutter 5 has to be an inverted gutter type or an inverted bowl type, and the shutter 5 is limited to a structure swinging in the direction of arrow R as shown in FIG. I didn't get it.

Therefore, an object of the present invention is to provide a vapor deposition plating method capable of efficiently irradiating an electron beam when the shutter is opened, without changing the shutter structure, and reliably preheating or keeping heat by the electron beam when the shutter is closed. To provide.

[0010]

DISCLOSURE OF THE INVENTION The present invention which has achieved the above object is to make the incident angle of electron beam irradiation on the upper surface of the plating material closer to the vertical direction when the shutter is opened than when the shutter is closed. It is a thing.

[0011]

In the present invention, the trajectory of electron beam irradiation on the upper surface of the plated material is changed between when the shutter is opened and when it is closed. However, when the shutter is opened, the trajectory of the electron beam is changed so that the incident angle on the top surface of the plating material is made closer to the vertical direction, which reduces the diffused reflection of the electron beam on the top surface of the plating material during the vapor deposition operation and reduces evaporation. Heat exchange is efficiently performed, and electron beam irradiation (projection) is performed on the top surface of the plated material.
The area is small, and high-density concentrated irradiation can be performed. Further, even if the upper surface of the plated material is vertically displaced, the fluctuation of the incident angle can be suppressed to a small level, so that the vapor amount does not fluctuate and the plating quality does not deteriorate.

The above-mentioned electron beam locus conversion is preferably performed by changing the deflection magnetic field by the deflection coil, and the electron beam scanning locus at the time of opening and closing the shutter is set so as to be adjusted by the output of the deflection coil. Is desirable. Further, it is recommended to temporarily stop the generation of the electron beam or reduce it to a small output when changing the trajectory of the electron beam to prevent erroneous irradiation to parts other than the plated material.

[0013]

FIG. 1 is an explanatory view showing an embodiment of electron beam irradiation in the method of the present invention. The arrangement positions of the crucible 2, shutter 5, electron gun 3 and plated material 6 are the same as those of the conventional example shown in FIG. It is the same, and the electron beam trajectory is changed as follows. That is, when the shutter closed, the shutter 5 is moved to the position shown in 5a, the electron beam trajectory B ₁ represents a low incident angle theta ₁ to the plating material 1 through the lower portion of the shutter as shown in FIG.
It is configured to irradiate with. At this time, since the plating material is only preheated or kept warm, a large output of the electron beam is not required, and a large amount of irregular reflection depending on the irradiation angle and a low irradiation density are not so important.

When the shutter 5 is opened, the magnetic field of the deflection coil is made stronger than when the shutter 5 is closed, the bending radius of the electron beam trajectory B ₂ is made smaller, and the incident angle satisfies the relation of θ ₁ <θ _2. The incident angle θ ₂ in the vertical direction. As a result, the amount of irregular reflection of the beam is reduced, the irradiation density is increased, and the plating material can be efficiently evaporated or sublimated.

It is preferable to change the current setting values of the scanning coils 33 and 34 at the same time when the electron beam locus is changed by the deflection coil. The scanning locus on the plated material upper surface 1A in accordance with the electron beam trajectories B ₁ and B _2. Allow Bk to be set in a wide range. Further, it is desirable to stop the generation of the electron beam for several tens of seconds or reduce the output to a small output when the shutter 5 is opened and closed. This prevents erroneous irradiation of the electron beam on the shutter 5 and delays the beam path due to the delay due to the reactance of the deflection coil. Confirmed, electron beam is plated 1
Prevents accidental irradiation of parts other than the surface of. Although the temperature of the plated material is slightly lowered by the suspension or reduction of the electron beam, it does not cause solidification or the like and does not cause a serious adverse effect.

For example, when the incident angle of the electron beam is changed from 20 degrees to 30 degrees, the irradiation density is improved by about 1.5 times, which enables efficient evaporation or sublimation. Further, at this time, the amount of movement of the beam irradiation position due to the height change of the plated material can be reduced to about 2/3, and it is possible to suppress the fluctuation of the amount of plating evaporation. Further, the smaller the incident angle, the higher the probability of erroneous beam irradiation on the upper surface of the crucible and the like, and there is the inconvenience that variations in the deposition amount and adhesion defects are more likely to occur.

[0017]

According to the present invention, the plating material can be efficiently evaporated or sublimated by effectively utilizing the heat quantity of the electron beam. Further, even when the upper surface of the plated material fluctuates or the electron beam scanning locus moves, fluctuations in the density and angle of electron beam irradiation can be reduced, so that a vapor-deposited product of stable quality can be manufactured.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of vapor deposition plating according to the method of the present invention.

FIG. 2 is an explanatory diagram showing an example of an evaporated state of a plated material due to electron beam irradiation.

FIG. 3 is a cross-sectional explanatory view showing a structural example of an electron gun.

FIG. 4 is an explanatory diagram showing an example of vapor deposition plating by a conventional method.

[Explanation of symbols]

 1 plated material 2 crucible 3 electron gun 4a, 4b deflection coil 5 shutter 6 plated material

Claims (1)

[Claims] 1. An upper surface of a plated material in a crucible is irradiated with an electron beam from an electron gun provided at a side portion of the crucible to perform vapor deposition plating on a material to be plated above the crucible. In the electron beam evaporation plating method, in which a shutter for blocking the rise of the plating material vapor is arranged between the plating material and the material to be plated, when the shutter is opened, the incident angle of the electron beam irradiation on the upper surface of the plating material is set to be smaller than that when the shutter is closed. An electron beam vapor deposition plating method characterized in that the electron beam evaporation plating is performed in the vertical direction.