JPH06316762A - Vapour deposition method excellent in evaporating efficiency - Google Patents

Abstract

PURPOSE:To obtain excellent evaporating efficiency at the time of evaporating under heating from the surface of a Zr-Cr alloy plating bath by an electron beam. CONSTITUTION:This vapour deposition method is excellent in evaporating efficiency in which the surface of a Zr-Cr alloy plating bath is evaporated under heating in such a manner that the irradiation position of an electron beam is continuously or intermittently moved, and in which the electron beam continuous irradiating time for one place on the surface of the Zr-Cr alloy plating bath is regulated to be <=10msec.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor deposition method having excellent vaporization efficiency, and more particularly to a coating method such as vacuum vapor deposition of Cr and Yep plating, and particularly in industrial fields such as building materials, home electric appliances and automobiles. Relates to a vapor deposition method excellent in evaporation efficiency of a sublimable substance used for plating for imparting corrosion resistance and abrasion resistance.

[0002]

2. Description of the Related Art Conventionally, in industrial fields such as building materials, home electric appliances and automobiles, Cr plating has been widely used for imparting corrosion resistance, wear resistance and aesthetics to materials such as interior materials, home appliance chassis and moldings. Has been used.

An electroplating method is a typical method of Cr plating. However, at the time of electroplating, 6
Due to the use of valent chromium, strict control of the working environment and waste liquid treatment have become problems. Further, there is complexity in the process of performing Ni pre-plating in order to secure the adhesion of Cr plating.

Recently, as research and development of a new plating process have been conducted, attention has been paid to the application of metal coating by a vapor deposition method instead of the electroplating method of Cr. According to this method, the generation of harmful substances such as hexavalent chromium can be prevented, and basically, after degreasing,
By plating by raising the substrate temperature in a vacuum atmosphere, it is possible to manufacture a Cr-plated material having good plating adhesion without performing pre-plating.

When the substrate is plated by this vapor deposition method, it is necessary to heat the plating raw material to a temperature at which a sufficient vapor pressure can be obtained. The heating means include resistance heating and electron beam heating. There is a method. And, for example, Cr
When it is necessary to heat to a considerably high temperature in order to obtain a sufficient vapor pressure that does not cause a problem in plating with, the electron beam heating method is generally used in many cases.

When the electron beam heating method is performed in this manner, high density energy can be applied to the surface of the plating raw material. However, since Cr has a sublimation property, C
When r is irradiated with an electron beam to evaporate it, only the irradiation surface is reduced and a recess is formed without being melted in a solid state. Therefore, the shape of the evaporation surface becomes non-uniform, which causes fluctuations in the evaporation speed and the evaporation direction.

As one of the methods for evaporating Cr in a molten state, the use of an alloy bath has been proposed (Japanese Patent Laid-Open No. Sho 62-020865), in which the vapor pressure of Cr is the same. A metal that is significantly smaller than the vapor pressure,
An alloy bath containing Cr is used, and it is expected that other metals are not substantially evaporated in the temperature range where Cr is evaporated.

Further, Japanese Patent Laid-Open No. 03-017066 proposes to use a Zr-Cr alloy bath, but as described above, in addition to utilizing the difference in vapor pressure between the two metals. , The melting point of Cr is lowered by constructing an alloy bath in which Zr and Cr are in the vicinity of the eutectic composition, and is intended to be melted in a temperature range where Cr is evaporated. Then, in the alloy plating bath made of Zr-Cr
It was found that the evaporation efficiency does not increase so much simply by electron beam irradiation.

This will be described with reference to the conventional example shown in FIG. FIG. 2 is a cross-sectional view when the electron beam 5 is applied to one point on the surface of the Zr—Cr alloy bath 1, and in the portion irradiated with the electron beam 5, Cr having a higher vapor pressure than Zr is preferentially applied. Evaporate in the direction of arrow 4.

Then, the Cr concentration in the bath where the electron beam 5 is irradiated to the Zr-Cr alloy bath 1 is lowered, and the evaporation rate of Cr is reduced in the vicinity of the Cr-deficient portion 2. This C
In the r-deficient portion 2, Cr newly flows due to diffusion or convection of Cr in the bulk bath and is replenished in the direction of arrow 3.

However, the diffusion rate of Cr is smaller than the evaporation rate, and a large flow of convection may not be expected depending on the shape of the crucible and the electron beam irradiation position. Therefore, Zr-
When irradiation and evaporation are continued at one point on the surface of the Cr alloy bath 1, the evaporation rate is such that the replenishment of Cr in the bath is reduced and a sufficient evaporation rate cannot be obtained.

[0012]

DISCLOSURE OF THE INVENTION The present invention solves various problems in the vapor deposition technique proposed in the above-mentioned explanation of the prior art or the publication, and in the vapor deposition method as seen in the prior art. Therefore, as a result of extensive studies and studies by the present inventor, excellent evaporation efficiency can be obtained by irradiating an electron beam, and further evaporation with excellent evaporation efficiency without fluctuation in evaporation rate and evaporation direction. The law was developed.

[0013]

According to the vapor deposition method of the present invention, which is excellent in vaporization efficiency, the surface of an alloy plating bath made of Zr-Cr is heated and vaporized by continuously or intermittently moving the irradiation position of an electron beam. This is a vapor deposition method with excellent evaporation efficiency, and the continuous electron beam irradiation time at one location on the surface of the alloy plating bath made of Zr—Cr is set to 10 msec or less.

The vapor deposition method having excellent evaporation efficiency according to the present invention will be described in detail and specifically below.

The vapor deposition method excellent in evaporation efficiency according to the present invention is
This is a solution to the problem of the position of electron beam irradiation in the various conventional techniques described above, that is, by moving the electron beam irradiated to the surface of the Zr—Cr alloy plating bath, it is possible to suppress the decrease in the evaporation rate. It turned out.

When the Zr--Cr alloy plating bath is irradiated with an electron beam, selective evaporation of Cr and deficiency of Cr occur at the electron beam irradiation position, but the electron beam irradiation position immediately moves. Therefore, evaporation continues to occur at the new position of the destination.

At the position where the electron beam was irradiated, C from the bulk bath was transferred while the electron beam was moving to another position.
Since r is replenished, when the electron beam is irradiated again after a predetermined time, the Cr concentration in the bath is sufficient to evaporate.

Therefore, by moving the electron beam irradiation position on the surface of the Zr-Cr alloy plating bath, C
Since evaporation of r → replenishment is performed in parallel at different positions, continuous evaporation can be performed with good evaporation efficiency.

Sufficient effects can be obtained in any movement state of the electron beam irradiation position on the surface of the Zr-Cr alloy bath, either continuously or intermittently. Then, in order to obtain a sufficient evaporation efficiency, it is sufficient that Cr evaporation → diffusion replenishment be performed at different positions substantially in parallel at the same time as described above, and the electron beam irradiation is intermittently performed. This is because even if the position is moved, these behaviors are not interrupted or hindered.

The irradiation time of the electron beam on one surface of the Zr-Cr alloy bath is preferably 10 msec or less. If the irradiation time is too long, the Cr content of Cr may be increased by the time the electron beam finishes moving to another position. Deficiency occurs, which leads to deterioration of evaporation efficiency due to a decrease in evaporation rate.

Depending on the target evaporation rate,
In order to obtain a sufficient evaporation rate that causes no practical problems, it is desirable that the continuous electron beam irradiation time at one location on the surface of the Zr—Cr alloy plating bath is 10 msec or less.

[0022]

[Example] An example of a vapor deposition method excellent in evaporation efficiency according to the present invention will be described.

[0023]

[Examples] As a material to be plated, a cold-rolled steel sheet of 0.7 mm ^t x 150 mm ^w x about 300 m ^I that had been subjected to alkaline degreasing treatment was used. As a plating alloy bath, Zr-20w
Internal volume of t% Cr 250 mm ^w x 150 mm ^I x 80 mm
^It was housed in a graphite crucible of ^h .

The heating of the Zr-Cr alloy plating bath was performed by irradiating an electron beam having a beam diameter of about 10 mmφ from the direction perpendicular to the plate passing direction. The beam diameter of the electron beam in this case is the non-magnetic SUS304 plate provided on the crucible,
The diameter of the hole formed by melting the SUS304 plate when irradiated with an electron beam was used. 1, plating bath 1, steel strip 7, electron beam 5
A schematic perspective view of the equipment of the crucible 6 is shown.

The electron beam scanning was performed by reciprocally moving the irradiation length shown in Table 1 in a predetermined direction in the sheet passing direction at a portion located directly below the widthwise central portion of the steel strip. The irradiation length L (mm) is the entire width in the longitudinal direction irradiated with the electron beam. L = M + D L: Irradiation length (mm) M: Moving length of beam center (mm) D: Beam diameter (mmφ) Here, since beam diameter is 10 mmφ, irradiation length (mm) = beam center Moving length (mm) +1
It becomes 0 (mm).

The period T (msec) is the time required for the electron beam to make one round trip in the longitudinal direction and then return to the original irradiation position. Also, irradiation time at one location X (msec)
Was calculated as the time required to move the irradiation length corresponding to the beam diameter of 10 mm by the following formula.

The electron beam is not irradiated in the width direction in order to compare the evaporation efficiency with the case where the electron beam irradiation is fixed at one place in Comparative Example 5, and the evaporation efficiency is determined by plating the central portion in the width direction of the steel strip. This is because the amount of adhesion was evaluated.

The evaporation efficiency was evaluated by the amount of Cr adhering to the steel strip when the steel strip was passed through the steel strip at a speed of 5 m / min while the electron beam power was kept constant at 20 kW. That is, the larger the amount of Cr, the better the evaporation efficiency.

Table 1 shows the difference in the amount of plating deposited when the irradiation time and period are controlled while the electron beam power is kept constant and the irradiation time at one location is changed.

[0030]

[Table 1]

The following is clear from Table 1. The Cr plating deposition amount when the electron beam irradiation position is moved shows a larger value than in Comparative Example 5 where the electron beam irradiation position is not moved. Furthermore, the electron beam continuous irradiation time at one location is set to 10 mse
By setting the value to be c or less, the Cr deposition amount stably shows a large value, which suggests that the evaporation efficiency is high.

[0032]

As described above, since the vapor deposition method according to the present invention which is excellent in evaporation efficiency has the above-mentioned constitution, Zr-C is used.
Excellent evaporation efficiency can be obtained when the surface of the r alloy plating bath is heated and evaporated by an electron beam.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a typical example of a vapor deposition method with excellent evaporation efficiency according to the present invention.

FIG. 2 is a perspective view showing a behavior during electron beam irradiation in a conventional vapor deposition method.

[Explanation of symbols]

 1 ... Zr-Cr alloy bath 2 ... Cr deficient portion in bath 3 ... Cr flow in bath 4 ... Cr vapor flow 5 ... Electron beam 6 ... Crucible 7 ... Steel strip

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Atsushi Kihara Atsushi Kihara 2222 Ikeda development, Ikeda, Onoue-cho, Kakogawa City, Hyogo Prefecture Within the Kakogawa Research Area, Kobe Steel Works, Ltd. (72) Kuniyasu Aragaga Kakogawa City, Hyogo Prefecture 2222, Ikeda Development, Ikeda, Onoe-machi, Kakogawa Research Area, Kobe Steel, Ltd.

Claims (2)

[Claims] 1. A vapor deposition method with excellent vaporization efficiency, characterized in that the surface of an alloy plating bath made of Zr—Cr is heated or vaporized by continuously or intermittently moving the irradiation position of an electron beam. 2. The vapor deposition method with excellent evaporation efficiency according to claim 1, wherein the continuous electron beam irradiation time at one location on the surface of the Zr--Cr alloy plating bath is 10 msec or less.