Mg2Si coating technology on magnesium alloys to improve corrosion and wear resistance

Magnesium silicide (Mg2Si) bulky materials are useful to improve the surface function of light metals such as magnesium or aluminum alloys, due to its superior corrosion resistance to the conventional stainless steel, and its high mechanical properties. In this study, Mg2Si thin film coated on AZ31 magnesium alloys by using a high frequency sputtering method, was examined. A neutral salt spray test to evaluate the corrosion resistance indicated that AZ31 substrate with Mg2Si coating was hardly damaged after 240 h. On the other hand, the non-treated one was corroded in only I h. Concerning wear resistance under the oil lubricant test, a friction coefficient of the AZ31 alloy with Mg2Si film is remarkably stable in employing S35C steel as a counter specimen. No sticking between both specimens was detected. In the combination of AZ31 alloy disc and S35C pin specimens, seizure and sticking phenomena occurred and the it value suddenly increased. Accordingly, Mg2Si coating technology is a suitable surface modification process to improve corrosion and wear resistance of magnesium alloys.