Effect of microstructure and texture of AZ31 magnesium alloy substrate on nucleation and growth of biomimetic calcium phosphate coating

Abstract

Magnesium has a special place in biomedical applications due to its biocompatibility and biodegradability properties. The high corrosion rate of magnesium in the body environment requires the use of a biocompatible coating such as calcium phosphate. In this paper, the effect of microstructure and crystalline texture of AZ31 magnesium alloy substrate on the morphology of calcium phosphate coating and the corrosion behavior of the material was investigated. The results imply that apatite crystals can form and grow on the surfaces of the biomimetic coating after soaking in simulated body fluid (SBF). The corrosion behavior of the material was investigated using an electrochemical polarization test in SBF solution for 3 days. The results showed that changes in the microstructure and crystalline texture of the substrate changed the coating morphology so that the growth of calcium phosphate changed from a rod-shaped with a diameter of 100–150 nm to a blade-shaped with a thickness of 20–50 nm. An increase in the corrosion resistance of the coated specimens with the corrosion rate of 0.65 mm/year was obtained compared to the uncoated specimen with the corrosion rate of 2.62 mm/year.

Keywords

• Magnesium alloys
• Hot rolling
• Biomimetic calcium phosphate coating
• Microstructure
• Simulated body fluid