Abstract
Coating technology by using magnesium silicide intermetallics (Mg2Si) was developed to improve the surface properties of magnesium alloys. This is because they have superior corrosion resistance to the conventional stainless steel and high Young's modulus and hardness. In this study, Mg-Si thin film deposited on AZ31 magnesium alloys by using a high frequency sputtering method was examined when employing the sintered Mg2Si bulky materials as sputtering targets. The change in the sputtering Ar gas pressure enables the structure control of Mg-Si thin film; crystal structures at lower pressure and amorphous one over 4 Pa. Some results of SST to evaluate the corrosion resistance indicated that AZ31 substrate with Mg-Si coating showed no damage after 240 h. On the other hand, that with no coating was corroded within only 1 h, and showed remarkably damaged surfaces. Pin on disk type wear test under oil lubricant indicated that a friction coefficient, μ was low and stable in using AZ31 alloy disk specimen coated by Mg-Si film. The disk specimen with no coating showed severely damaged surface including seizure or sticking phenomena with S35C pin specimens. In particular, the amorphous Mg-Si film showed superior anti-seizure properties to the crystalline one because of higher hardness and Young's modulus.
