Surface characterization and corrosion behavior of calcium phosphate (Ca-P) base composite layer on Mg and its alloys using plasma electrolytic oxidation (PEO): A review

Magnesium has been known as an appropriate biological material on account of its good biocompatibility and biodegradability properties in addition to advantageous mechanical properties. Mg and its alloys are of poor corrosion resistance. Its high corrosion rate leads to its quick decomposition in the corrosive ambiance and as a result weakening its mechanical properties and before it is repaired, it will vanish. The corrosion and degradation rate must be controlled in the body to advance the usage of Mg and its alloys as implants. Different techniques have been utilized to boost biological properties. Plasma electrolytic oxidation (PEO) can provide porous and biocompatible coatings for implants among various techniques. Biodegradable implants are generally supposed to show enough corrosion resistance and mechanical integrity in the body environment. Much research has been carried out in order to produce PEO coatings containing calcium phosphate compounds. Calcium phosphates are really similar to bone mineral composition and present great biocompatibility. The present study deals with the usage of calcium phosphates as biocompatible coatings applied on Mg and its alloys to study the properties and control the corrosion rate.