Rapid coating of \AZ31\ magnesium alloy with calcium deficient hydroxyapatite using microwave energy

By Yufu Ren and Huan Zhou and Maryam Nabiyouni and Sarit B. Bhaduri
Published in Materials Science and Engineering: C NULL 2015

Abstract

Due to their unique biodegradability, magnesium alloys have been recognized as suitable metallic implant materials for degradable bone implants and bioresorbable cardiovascular stents. However, the extremely high degradation rate of magnesium alloys in physiological environment has restricted its practical application. This paper reports the use of a novel microwave assisted coating technology to improve the in vitro corrosion resistance and biocompatibility of Mg alloy AZ31. Results indicate that a dense calcium deficient hydroxyapatite (CDHA) layer was uniformly coated on a \AZ31\ substrate in less than 10 min. Weight loss measurement and \SEM\ were used to evaluate corrosion behaviors in vitro of coated samples and of non-coated samples. It was seen that \CDHA\ coatings remarkably reduced the mass loss of \AZ31\ alloy after 7 days of immersion in SBF. In addition, the prompt precipitation of bone-like apatite layer on the sample surface during immersion demonstrated a good bioactivity of the \CDHA\ coatings. Proliferation of osteoblast cells was promoted in 5 days of incubation, which indicated that the \CDHA\ coatings could improve the cytocompatibility of the \AZ31\ alloy. All the results suggest that the \CDHA\ coatings, serving as a protective layer, can enhance the corrosion resistance and biological response of magnesium alloys. Furthermore, this microwave assisted coating technology could be a promising method for rapid surface modification of biomedical materials.

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