Preparation and in vitro degradation characterization of Si-containing coating on AZ31B alloy

Surface modification can be an effective way to control the biodegradation behaviour of magnesium alloys. In the present study, Si-containing coating was prepared on the surface of AZ31B alloy to decrease the degradation of the alloy by a chemical deposition method. The degradation behaviour of Si-containing coating in simulated body fluid was discussed. The results showed that the coating was mainly composed of Mg2SiO4, MgO and SiO2. The formation mechanism of the Si-containing coating on AZ31B alloy was proposed. The bonding strength of the coating with the substrate was higher than 24MPa. The degradation of the coated alloy in simulated body fluid decreased compared to that of the uncoated alloy. Apatite was formed on the surface of Si-containing coated AZ31B alloy after immersion in Hank's solution. The degradation mechanism of the Si-containing coated AZ31B alloy in Hank's solution is proposed. It is concluded that Si-containing coating results in decreased degradation of AZ31B alloy, making it more suitable for clinical application.