Magnesium alloy micro-arc oxidation black ceramic membrane and preparation method thereof

Abstract

The invention discloses a magnesium alloy micro-arc oxidation blackness ceramic membrane and a preparation method thereof. The preparation method comprises the steps: a magnesium alloy is polished through SiC abrasive paper, then subjected to deoiling washing, blow-dried through an electric air blower, and placed into a drier for standby application; and the magnesium alloy serves as an anode, a stainless steel sheet serves as a cathode, the pretreated magnesium alloy is soaked in an electrolyte, the magnesium alloy is subjected to micro-arc oxidation in a bipolar pulse constant current mode,then taken out to be washed through deionized water and dried, and then the black ceramic membrane is obtained. Under the condition that electric parameters are not changed, a membrane forming promoter, namely carbohydrazide is added into the electrolyte, the arcing voltage is lowered, the membrane layer quality is improved, thus the membrane layer corrosion resisting property is good, the black ceramic membrane has the small blackness value, even color and firmer membrane-based combination, and the advantages that the prepared membrane layer quality is high, the preparation efficiency is high, and unit energy consumption is low are achieved.

Description

technical field [0001] The invention belongs to the field of magnesium alloy surface treatment, in particular to a smooth micro-arc oxidation black ceramic film of magnesium alloy and a preparation method thereof. Background technique [0002] Magnesium alloy is the lightest metal structure material. It has the advantages of light specific gravity, high specific strength, good vibration damping, strong electromagnetic shielding, and easy recycling. It is considered to be the most potential development and application in the 21st century. "Material. In recent years, with the rapid popularization of 3C electronic products, their shells have also undergone upgrading, and the original engineering plastics with poor texture have gradually developed into metal materials. Among the common metal materials, magnesium alloy has the advantages of low density, high specific strength and high rigidity, which can provide sufficient protection while meeting the requirements of light weigh...

AI Technical Summary

Problems solved by technology

However, there are many technical disadvantages in anodic oxidation coloring: (1) The oxide film formed by anodic oxidation is relatively brittle, has poor bonding performance with the substrate, and is easy to fall off under stress conditions; under many conditions, it must be processed with resin or coating. Sealing makes the process more cumbersome; (2) The anodic oxidation electrolyte is often acidic, which is very harmful to the environment; (3) The anodic oxidation coloring is a two-step coloring, that is, the anodic oxidation film is first formed, and then placed in other electrolytes electrolytic coloring

[0005] At present, the research on the micro-arc oxidation coloring of magnesium alloys is mainly concentrated in China, and there are mainly the following deficiencies: (1) The solution contains highly toxic substances; for example, the micro-arc oxidation coloring is carried out on the surface of magnesium alloys by adding potassium bicatalyst (Yuan Xufang Preparation of dark ceramic film by micro-arc oxidation of rare earth magnesium alloy[D].2008 Changchun University of Science and Technology Master's Degree Thesis)

However, the required pretreatment process includes degreasing, surface activation, surface adjustment and other processes, which increases the operation links and makes the process complicated, which is not conducive to the actual industrial production application

Images