Incorporation of Al<sub>2</sub>O<sub>3</sub> and ZrO<sub>2</sub> ceramics to AZ31 magnesium alloys composite coating using micro-arc oxidation method.

Askarnia, R; Sobhani, M; Zare, M; Aghamohammadi, H; Staji, H · J Mech Behav Biomed Mater · 2023

basic_science · Level V

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Abstract

In this research, a composite coating with Al<sub>2</sub>O<sub>3</sub> and ZrO<sub>2</sub> particles have been applied on AZ31 magnesium alloy by micro-arc oxidation (MAO) technique. The alkaline electrolyte included a constant based composition and different composition of the Al<sub>2</sub>O<sub>3</sub> and ZrO<sub>2</sub> additives. Microstructure observations reveal that the surface pores of composite coating reduced during addition of ZrO<sub>2</sub> and Al<sub>2</sub>O<sub>3</sub> ceramic particles. The hardness of coating increased from about 380 for non-added to 620 MPa for Al<sub>2</sub>O<sub>3</sub>+ZrO<sub>2</sub> added coating and wear rate reduced about 8 times. Wettability of the coating increased by incorporation of Al<sub>2</sub>O<sub>3</sub> and/or ZrO<sub>2</sub> particles while, Al<sub>2</sub>O<sub>3</sub> is more effective than ZrO<sub>2</sub>. Addition of the ceramic particles enhanced the hydrophilicity properties of surface in wettability test and a contact angle of 43° was obtained for coating including Al<sub>2</sub>O<sub>3</sub>+ZrO<sub>2</sub>. The antibacterial properties of MAO coatings showed that S. aureus bacterium is more sensitive to the zirconia and alumina particle than S. typhimurium bacterium after 24 h of incubation.

Medical subject headings