1. Field of the Invention
The present invention generally relates to a surface treatment and, more particularly, to a surface treatment of a magnesium alloy.
2. Description of the Related Art
Magnesium is a light-weight metal with properties (such as density and coefficient of elasticity) similar to periosteum, and also, magnesium is a bio-degradable material with great mechanical properties. Thus, a magnesium alloy containing magnesium and other metals poses potential to use as a biomaterial to replace other biomaterials, such as titanium alloy or stainless steel.
However, the magnesium alloy shows poor corrosion resistance and degrades rapidly in vivo, releasing excess magnesium ions (Mg2+) and hydrogen ions (H+) within a short time. Although magnesium ions are usable in human bodies, the accumulated, excess hydrogen ions will reduce pH values of body fluids, causing the insufficient oxygen supply to tissues, thereby leading to abnormality of human bodies.
In light of this, it is necessary to provide a surface treatment of the magnesium alloy, solving the difficulty in rapidly degradation in vivo.