Surface coating method for piston

Abstract

The surface coating method for the piston comprises the following steps: cleaning and drying the piston; placing the piston and the metal target in a vacuum chamber, introducing argon, and controlling the air pressure to be at a first value so as to form a metal layer on the surface of the piston through sputtering; and hydrocarbon type gas is introduced into the vacuum chamber, the air pressure is controlled to be at a second value, and the second value is smaller than the first value, so that a diamond-like carbon layer is deposited on the metal layer. The method is simple and easy to implement and low in cost, the surface hardness of the piston can be improved, the treated piston surface is smooth and compact, a film body is not prone to stripping, and the service life of the piston is prolonged.

Description

Technical Field

[0001] The invention relates to the field of film coating, and in particular to a surface coating method for a piston. Background Art

[0002] Pistons are basic parts in mechanical manufacturing. During the movement, these parts will cause certain wear on the contact surface, which will affect the transmission effect and shorten the service life of the parts. A common improvement method is to coat the piston surface with a layer of metal film such as pick, titanium, etc. to increase the hardness of the piston, reduce wear and reduce friction. However, this method of coating is inseparable from the high-temperature heating process. High temperature can easily damage the piston and make the surface rough. It also causes the metal film to peel off and fall off. In addition, the manufacturing cost of this treatment is high.

[0003] Therefore, it is necessary to provide a piston surface coating method to overcome the above defects. Summary of the invention

[0004] The purpose of the present invention is to provide an improved piston surface coating method, which is simple and easy to implement, has low cost, can improve the surface hardness of the piston, and the surface of the piston after treatment is smooth and dense, the film is not easy to peel off, and the service life of the piston is increased.

[0005] To achieve the above object, the surface coating method of a piston of the present invention comprises the following steps:

[0006] Clean and dry the piston;

[0007] Placing the piston and the metal target in a vacuum chamber, introducing argon gas, and controlling the gas pressure to be at a first value to sputter and form a metal layer on the surface of the piston; and

[0008] A hydrocarbon gas is introduced into the vacuum chamber, and the gas pressure is controlled to be at a second value, which is smaller than the first value, so as to deposit a diamond-like carbon layer on the metal layer.

[0009] Compared with the prior art, the surface coating method of the present invention first forms a metal layer on the surface of the piston by sputtering in a vacuum chamber in an argon environment, and then deposits a diamond-like carbon layer on the metal layer. By means of the close connection between the diamond-like carbon layer and the metal layer, and the close connection between the metal layer and the piston surface, a dense and firm diamond-like carbon layer is formed on the surface of the piston. The diamond-like carbon layer has high hardness, is smooth and dense, and is not easy to wear, thereby increasing the service life of the piston; moreover, the metal layer serves as a transition layer between the diamond-like carbon protective layer and the piston surface, making the diamond-like carbon protective layer more firm and not easy to peel off and fall off. Furthermore, the method of the present invention is mainly carried out in a vacuum chamber, and only the working parameters such as the gas and air pressure in the vacuum chamber need to be controlled. It is very simple, easy to operate, and low in cost.

[0010] Preferably, forming the metal layer further comprises: controlling the workpiece bias voltage to 100-150V, adjusting the magnetron power supply of the metal target, the sputtering power to 500-700W, and the sputtering time to 60-90 minutes.

[0011] Preferably, the first value is 5.0-10.0Pa.

[0012] Preferably, the metal target is a Cr target, a Ti target or a Zr target.

[0013] Preferably, the thickness of the metal layer is 8-13 μm.

[0014] Preferably, depositing the diamond-like carbon layer further comprises: using ion beam deposition, the working voltage applied to the ion beam is greater than 1500V, and the working current is 100-200mA.

[0015] Preferably, depositing the diamond-like carbon layer further comprises: applying a pulse bias voltage greater than 500V to the workpiece, and the deposition time is 50-100 minutes.

[0016] Preferably, the second value is 0.05-0.5Pa.

[0017] Preferably, the thickness of the diamond-like carbon layer is 15 μm. DETAILED DESCRIPTION

[0018] The surface coating method of the piston of the present invention is further described below in conjunction with the embodiments, but the present invention is not limited thereby. The method of the present invention aims to provide a surface coating method of the piston, which is simple and easy to implement, low in cost, can improve the surface hardness of the piston, and the surface of the piston after treatment is smooth and dense, the film body is not easy to peel off, and the service life of the piston is improved.

[0019] In one embodiment of the surface coating method of the piston of the present invention, the following steps are included:

[0020] Clean and dry the piston;

[0021] Placing the piston and the metal target in a vacuum chamber, introducing argon gas, and controlling the gas pressure to be at a first value to sputter and form a metal layer on the surface of the piston; and

[0022] A hydrocarbon gas is introduced into the vacuum chamber, and the gas pressure is controlled to be at a second value, which is smaller than the first value, so as to deposit a diamond-like carbon layer on the metal layer.

[0023] The surface coating method of the present invention first forms a metal layer on the surface of the piston by sputtering in a vacuum chamber in an argon environment, and then deposits a diamond-like carbon layer on the metal layer. By virtue of the close connection between the diamond-like carbon layer and the metal layer, and the close connection between the metal layer and the piston surface, a dense and firm diamond-like carbon layer is formed on the surface of the piston. The diamond-like carbon layer has high hardness, is smooth and dense, and is not easy to wear, thereby increasing the service life of the piston; moreover, the metal layer serves as a transition layer between the diamond-like carbon protective layer and the piston surface, making the diamond-like carbon protective layer more firm and not easy to peel off and fall off. Furthermore, the method of the present invention is mainly carried out in a vacuum chamber, and only the working parameters such as the gas and air pressure in the vacuum chamber need to be controlled. It is very simple, easy to operate, and low in cost.

[0024] Specifically, the formation of the metal layer and the diamond-like carbon layer of the present invention is carried out in a vacuum chamber, and the formation of the film is achieved by controlling the gas, vacuum degree and working conditions.

[0025] Specifically, before the piston is placed in the vacuum chamber, it is first cleaned and dried to facilitate better coating. For example, it can be cleaned with a conventional cleaning agent and then placed in an oven for low-temperature drying.

[0026] Next, the piston and the metal target are placed in a vacuum chamber, argon gas is introduced, and the gas pressure is controlled to be a first value, preferably 5.0Pa-10.0Pa. The workpiece bias is controlled to be 100V-150V, and the high-power magnetron power supply of the metal target is adjusted, the sputtering power is 500-700W, and the sputtering time is 60-90 minutes to obtain a metal layer. Preferably, the metal target is a Cr target, a Ti target or a Zr target, or a metal target mixed with one or more of the above metals. Optionally, the thickness of the metal layer is 8-13μm. Thus, a metal layer is formed. The metal layer serves as a transition layer between the subsequent diamond-like carbon protective layer and the piston surface, making the diamond-like carbon protective layer more firm and not easy to peel off and fall off.

[0027] Then, ion beam deposition is used to form a diamond-like carbon layer. Specifically, a hydrocarbon gas, such as CH4, is introduced into the vacuum chamber to maintain a vacuum degree of 0.05-0.5 Pa, close to a vacuum state, that is, the second value of the gas pressure is less than the first value when the metal layer is formed, and the vacuum degree is particularly conducive to the deposition of the diamond-like carbon layer. Specifically, the ion beam power supply is turned on to start deposition, the working voltage applied to the ion beam is greater than 1500V, and the working current is 100-200mA. Specifically, a pulse bias voltage greater than 500V is applied to the workpiece, the deposition time is 50-100 minutes, and the thickness is preferably 15μm. Thus, a diamond-like carbon layer is formed.

[0028] Through the above method, firstly, sputtering is performed in a vacuum chamber in an argon environment to form a metal layer on the surface of the piston, and then a diamond-like carbon layer is deposited on the metal layer. With the help of the close connection between the diamond-like carbon layer and the metal layer, and the close connection between the metal layer and the piston surface, a dense and firm diamond-like carbon layer is formed on the surface of the piston. The diamond-like carbon layer has high hardness, is smooth and dense, and is not easy to wear, thereby increasing the service life of the piston; moreover, the metal layer serves as a transition layer between the diamond-like carbon protective layer and the piston surface, making the diamond-like carbon protective layer more firm and not easy to peel off and fall off. Furthermore, the method of the present invention is mainly carried out in a vacuum chamber, and only the working parameters such as the gas and air pressure in the vacuum chamber need to be controlled. It is very simple, easy to operate, and low in cost, and is suitable for popularization and use in industry.

[0029] The above disclosure is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A method for coating a piston surface, characterized in that: The following steps are involved: Clean and dry the piston; Placing a piston and a metal target in a vacuum chamber, introducing argon gas, and controlling the gas pressure to be at a first value to sputter and form a metal layer on the surface of the piston; as well as A hydrocarbon gas is introduced into the vacuum chamber, and the gas pressure is controlled to be at a second value, which is smaller than the first value, so as to deposit a diamond-like carbon layer on the metal layer.

2. The method for coating the surface of a piston according to claim 1, characterized in that: The forming of the metal layer also includes: controlling the workpiece bias voltage to 100-150V, adjusting the magnetron power supply of the metal target, the sputtering power to 500-700W, and the sputtering time to 60-90 minutes.

3. The surface coating method of a piston according to claim 1, characterized in that: The first value is 5.0-10.0Pa.

4. The surface coating method of a piston according to claim 1, characterized in that: The metal target is a Cr target, a Ti target or a Zr target.

5. The surface coating method of a piston as claimed in claim 1, characterized in that: The thickness of the metal layer is 8-13 μm.

6. The method for coating the surface of a piston according to claim 1, characterized in that: Depositing the diamond-like carbon layer also includes: using ion beam deposition, with the working voltage applied to the ion beam being greater than 1500V and the working current being 100-200mA.

7. The surface coating method of a piston as claimed in claim 6, characterized in that: Depositing the diamond-like carbon layer also includes: applying a pulse bias voltage greater than 500V to the workpiece, and the deposition time is 50-100 minutes.

8. The method for coating the surface of a piston according to claim 1, characterized in that: The second value is 0.05-0.5Pa.

9. The surface coating method of a piston as claimed in claim 1, characterized in that: The thickness of the diamond-like carbon layer is 15 μm.