Preparation method of dlc protective film on aluminum alloy surface

Abstract

The invention discloses a preparation method for an aluminum alloy surface DLC (Diamond-like carbon) protection film. The film consists of a transition layer and an H-contained DLC layer, wherein thetransition layer is a Sic and Si-DLC mixed transition layer or a Sic and Si-DLC double-layer transition layer deposited on 7075 aluminum alloy, wherein the DLC layer is the H-contained DLC layer whichis directly generated, and the film is prepared by a CVD (Chemical Vapor Deposition) method. Firstly, the 7075 aluminum alloy is preprocessed, then, a hollow cathode electron gun and a lower focusingcoil are assisted as the ionization source of TMS (tetramethylsilane) gas and / or acetylene, negative bias is added to a matrix for deposition, and finally, nitrogen and acetylene gas which serves asa carbon source are used for disposition to generate H-contained DLC. The aluminum alloy surface DLC protection film disclosed by the invention has the advantages of good tribological property, smooth surface, high film base binding force, high hardness, simple technology and low cost.

Description

technical field [0001] The invention relates to an aluminum alloy surface protective film and a preparation process thereof, in particular to a preparation process using SiC and DLC as an additional protective film, and belongs to the technical field of aluminum alloy surface treatment and surface modification. Background technique [0002] Aluminum alloy has low density, excellent electrical and thermal conductivity, high strength, good plasticity and formability, and easy processing. It is widely used in aerospace, military industry, automobile, shipbuilding, construction and other fields. However, aluminum alloys have low hardness, poor wear resistance, and poor corrosion resistance, which greatly restrict the application prospects of aluminum alloys. Therefore, it is very important to treat the surface of aluminum alloys to provide effective protection and improve the surface properties of aluminum alloys. Commonly used aluminum alloy surface treatment methods include a...

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Problems solved by technology

The oxide film obtained by anodic oxidation treatment is relatively thick, so the corrosion resistance is better, but due to the poor adhesion of the film, high cost and unsatisfactory impact resistance of the film, it is rarely used in industrial production; the laser cladding method is easy Brittle phases and cracks are formed on the interface. In practical applications, problems such as dimensional accuracy of the film, tolerance to the complex shape of the substrate, and surface roughness are difficult to solve; the disadvantage of the rare earth conversion coating method is that the long-term immersion process of rare earth salt The time is long and the temperature required for processing is also high

However, in the process of modifying the DLC film on the surface of the aluminum alloy, people found that there are many difficulties. The thermal expansion coefficient of the aluminum alloy is large and the hardness is low, the matrix is ​​easy to soften, the mechanical properties are degraded, and the surface is easy to oxidize to form a dense oxide film. Limits the modification of the aluminum alloy surface by the DLC film, and the excellent mechanical properties of the film

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