CN102650036A - Method for coating ivory film on metallic casing - Google Patents

Abstract

The invention provides a method for coating an ivory film on a metallic casing. The method comprises the steps as follows: adopting a reactive megnetron sputtering coating process, taking pure chromium as a target and nitrogen as a reactant gas, and coating a chromium nitride film on the metallic casing; and adopting the reactive megnetron sputtering coasting process, taking pure chromium and pure aluminum as targets to carry out co-sputtering, taking oxygen as a reactant gas, and coating the ivory film formed by the chromium dioxide and aluminum dioxide on the chromium nitride film. The approximate power rate of an aluminum target and a chromium target is 12:1, the bias voltage of the reactive megnetron sputtering coating process remains between 180 V and 220 V, the temperature of the reactive megnetron sputtering coating process remains between 180 DEG C and 220 DEG C, and the period of time of the reactive megnetron sputtering coating process remains between 58 min to 62 min. In a CIE LAB surface color system, an L coordinate of a chromaticity region presented by the ivory film coated by adopting the reactive megnetron sputtering coating process remains between 86.15 and 86.25, an a coordinate remains between 0.425 and 0.435, and a b coordinate remains between 0.715 to 0.725.

Description

Method for forming milky white film layer on metal shell

technical field

The invention relates to the field of film coating, in particular to a method for forming a milky white film layer on a metal casing.

Background technique

Currently, some electronic device casings are welcomed by consumers due to their clean and elegant milky white color. These milky white shells are generally plastic shells, but metal shells that are stronger and more textured than plastic shells are rare because it is difficult to form milky white films.

Contents of the invention

In view of this, it is necessary to provide a method for forming a milky white film layer on the metal casing.

A method for forming a milky white film layer on a metal shell, comprising providing a metal shell; using a reactive magnetron sputtering coating process, using pure chromium as a target material, and nitrogen as a reactive gas to form a nitriding layer on the surface of the metal shell Chromium film layer: using the reactive magnetron sputtering coating process, co-sputtering with pure chromium and pure aluminum as the target, and using oxygen as the reactive gas, a layer composed of chromium oxide and aluminum oxide is formed on the chromium nitride film layer. The milky white film layer, the power ratio of the aluminum target and the chromium target being bombarded is about 12:1, the bias voltage of the reactive magnetron sputtering coating process is between 180 and 220 volts, and the temperature is between 180 and 220 degrees Celsius degrees, the time is between 58 and 62 minutes.

The chromaticity region of the milky white film layer plated by this method is between 86.15 and 86.25 in the CIE LAB color system, the a coordinate is between 0.425 and 0.435, and the b coordinate is between 0.715 and 0.725, which has a good The visual experience improves the aesthetics of the electronic device.

Description of drawings

Fig. 1 is a flow chart of the plating method of the milky white film layer of the preferred embodiment of the present invention.

FIG. 2 is a cross-sectional view of a metal shell coated with a film coated by the method of FIG. 1 . Description of main component symbols

metal case 1

Chromium nitride layer 2

Milky white film layer 3

Detailed ways

Please refer to Fig. 1 and Fig. 2, the plating method of the milky white film layer of preferred embodiment of the present invention comprises the following steps:

First, a metal case 1 is provided. The metal casing 1 can be the casing of an electronic product, and its material can be aluminum or stainless steel.

Next, a chromium nitride layer 2 is formed on the surface of the metal shell 1 . In this embodiment, the chromium nitride layer 2 is formed on the surface of the metal shell 1 by a reactive magnetron sputtering coating method. With pure chromium as the target material, nitrogen gas and argon gas with a ratio of about 2.3:1 are passed into the high vacuum plating chamber, for example, the flow rate of argon gas is 25 sccm, and the flow rate of nitrogen gas is 58 sccm. Under the action of electromagnetic field, nitrogen and argon gas are plasmaized to form plasma and accelerated to hit the pure chromium target material, the material on the surface of the pure chromium target material will be splashed out, and the nitrogen atoms will combine with it to form a chromium nitride film layer 2 on the surface of the metal shell 1 . Before the chromium nitride film layer 2 is plated, the surface of the metal shell 1 can be roughened or polished in advance, so as to improve the adhesion of the chromium nitride layer 2 .

Next, a milky white film layer 3 is formed on the surface of the chromium nitride layer 2 . In this embodiment, the milky white film layer 3 is also formed by reactive magnetron sputtering coating method. With pure chromium and pure aluminum as target materials, oxygen and argon gas with a ratio of about 3:2 are introduced into the high vacuum plating chamber, for example, the flow rate of oxygen is 300 sccm, and the flow rate of argon gas is 200 sccm. Under the action of electromagnetic field, oxygen and argon are plasmaized to form plasma to bombard pure chromium and pure aluminum targets respectively. Among them, the power ratio of the bombardment of the aluminum target and the chromium target is about 12:1. For example, the power of the aluminum target is 30 kW, and the power of the chromium target is 2.5 kW. Reactive magnetron sputtering coating The bias voltage of the process is between 180 and 220 volts, the temperature is between 180 and 220 degrees Celsius, and the time is between 58 and 62 minutes. Preferably, the metal casing 1 also revolves at a speed of 5 revolutions per minute (rpm), and at the same time rotates at a speed between 3.3 and 2.7 rpm, and the revolution direction is opposite to the rotation direction. The ratio of aluminum to chromium in the milky white film layer 3 is adjustable. When the content of aluminum is much lower than that of chromium, the milky white film layer 3 tends to present a metallic texture; when the content of aluminum is much higher than that of chromium, the milky white film layer 3 tends to present a ceramic texture. Therefore, by changing the ratio of aluminum to chromium, the milky white film layer 3 can gradually change from a metallic texture to a ceramic texture, or from a ceramic texture to a metallic texture.

According to the above steps, the required milky white film layer 3 can be formed on the chromium nitride layer 2 by co-sputtering, and the chromaticity area presented by the milky white film layer 3 is displayed on the International Commission on Illumination (Commission internationale de l'éclairag, CIE) LAB color The L coordinate of the system is between 86.15 and 86.25, the a coordinate is between 0.425 and 0.435, and the b coordinate is between 0.715 and 0.725. In addition, compared with the milky white film layer 3, the mutual bonding between the chromium nitride layer 2 and the metal shell 1 is better, and the mutual bonding force between the milky white film layer 3 and the chromium nitride layer 2 is stronger Therefore, the film layer plated by the plating method of the milky white film layer of the present invention has good wear resistance.

It can be understood that those skilled in the art can also make other changes within the spirit of the present invention for the design of the present invention, as long as they do not deviate from the technical effects of the present invention. These changes made according to the spirit of the present invention should be included in the scope of the present invention.

Claims (5)

1. method that on metal shell, forms the oyster white rete comprises:

Step 1 a: metal shell is provided;

Step 2: utilizing reaction formula magnetron sputtering membrane process, is target with pure chromium, is reactant gases with nitrogen, forms a chromium nitride film layer in this metal shell surface; And

Step 3: utilize reaction formula magnetron sputtering membrane process; With pure chromium and fine aluminium is target sputter altogether, is reactant gases with oxygen, the oyster white rete that formation one is made up of chromic oxide and aluminum oxide on this chromium nitride film layer; This aluminium target is about 12: 1 with the power ratio that this chromium target is bombarded; The bias voltage of this reaction formula magnetron sputtering membrane process is between 180 to 220 volts, and temperature is between 180 to 220 degree Celsius, and the time was between 58 to 62 minutes.

2. the plating method of oyster white rete as claimed in claim 1 is characterized in that, in the step 2, the nitrogen that in said reaction formula magnetron sputtering membrane process, in high vacuum is coated with the cabin, feeds and the ratio of argon gas are about 2.3: 1.

3. the plating method of oyster white rete as claimed in claim 2 is characterized in that, in the step 2, this argon flow amount is 25sccm, and this nitrogen flow is 58sccm.

4. the plating method of oyster white rete as claimed in claim 1 is characterized in that, the power that this pure chromium target is bombarded is 2.5 kilowatts, and the power that this fine aluminium target is bombarded is 30 kilowatts.

5. the plating method of oyster white rete as claimed in claim 1; It is characterized in that; In the step 3; The revolution rotating speed of this metal shell is 5 Revolution Per Minutes in said reaction formula magnetron sputtering membrane process, and the rotation rotating speed is between 3.3 to 2.7 Revolution Per Minutes, and this sense of rotation and this revolution are in the opposite direction.

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