Composite coating with anti-corrosion lubricating property of surface of magnesium alloy, preparation method thereof

Abstract

The invention discloses a composite coating with anti-corrosion lubricating property of the surface of magnesium alloy, which takes an MgO porous membrane as a transition layer, and the MgO porous membrane is positioned on the surface of a magnesium alloy substrate and is used for leading magnesium atoms of the surface layer of the magnesium alloy substrate to be formed in situ by adopting a micro-arc oxidation technology, and comprises (Si, N)-DLC or (Ti, N)-DLC multi-element nano-composite coating arranged on the surface of the transition layer. Compared with the prior art, the composite coating greatly improves the corrosion resistance and the wear resistance of the surface of the magnesium alloy substrate, has the nano-indentation hardness of 21-30GPa and the frictional factor with a steel ball of less than 0.15 or even less than 0.1, and is good in corrosion resistance, so that the composite coating with the anti-corrosion lubricating property has a good application prospect.

Description

technical field [0001] The invention belongs to the technical field of material surface coating, and in particular relates to a multi-component nano-composite coating on the surface of a magnesium alloy substrate with corrosion resistance and lubricating properties and a preparation method thereof. Background technique [0002] As a green and environmentally friendly high-performance lightweight alloy material, magnesium alloy has many advantages such as low density, high specific strength and specific stiffness, good dimensional stability, good electromagnetic shielding, and good shock absorption and processing performance. Under the current dual pressure of energy and environment, it has become a research and development hotspot of high-performance light alloy materials at home and abroad. my country is rich in magnesium resources, and a large number of automobile, hardware, sanitary ware, information products and other production and manufacturing enterprises have formed ...

AI Technical Summary

Problems solved by technology

[0003] At present, there are still two key problems in the research field of magnesium alloy materials: one is that due to the low electrode potential and high chemical activity of magnesium, severe corrosion will occur in humid air, sulfur-containing atmosphere, marine atmosphere and human environment. However, the loose oxide film formed by magnesium itself is difficult to provide effective protection for the substrate, resulting in poor corrosion resistance; secondly, magnesium alloy is soft in texture and low in hardness, and as a structural material, it is easy to cause component scrap due to wear and tear

However, there are still great difficulties in preparing DLC ​​thin films directly on the surface of magnesium alloys.

On the one hand, there is an inevitable accumulation of high residual compressive stress in the film, which not only leads to poor adhesion of the film base, easy peeling and failure of the film, but also greatly restricts the growth of thick films, which greatly limits its application.

On the other hand, it is more difficult to prepare a high-hardness DLC film on the surface of magnesium alloy, a material with high chemical activity and soft texture.

[0006] In traditional methods, transition layers such as Cr and CrN, and Me-DLC films with nanocomposite structures formed by doping metals in DLC films are also used to improve the surface properties of magnesium alloys, but there is a gap between the transition layers and the magnesium alloy matrix. Significant potential difference will easily lead to poor corrosion resistance, and Me-DLC film has no obvious improvement in corrosion resistance due to microscopic defects such as pinholes.

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