Incorporation of Al2O3 and ZrO2 ceramics to AZ31 magnesium alloys composite coating using micro-arc oxidation method

In this research, a composite coating with Al2O3 and ZrO2 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 Al2O3 and ZrO2 additives. Microstructure observations reveal that the surface pores of composite coating reduced during addition of ZrO2 and Al2O3 ceramic particles. The hardness of coating increased from about 380 for non-added to 620 MPa for Al2O3+ZrO2 added coating and wear rate reduced about 8 times. Wettability of the coating increased by incorporation of Al2O3 and/or ZrO2 particles while, Al2O3 is more effective than ZrO2. Addition of the ceramic particles enhanced the hydrophilicity properties of surface in wettability test and a contact angle of 43 degrees was obtained for coating including Al2O3+ZrO2. 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.

Automated summary

A composite coating with Al2O3 and ZrO2 particles was prepared on AZ31 magnesium alloy using micro-arc oxidation (MAO) technique. The addition of ZrO2 and Al2O3 ceramic particles reduced the surface pores of the composite coating. The hardness of the coating increased from about 380 to 620 MPa with the addition of Al2O3+ZrO2 particles and the wear rate decreased about 8 times. The wettability of the coating was improved by incorporating Al2O3 and/or ZrO2 particles, with Al2O3 being more effective than ZrO2. The antibacterial properties of the MAO coatings showed that Staphylococcus aureus bacteria were more sensitive to zirconia and alumina particles than Salmonella typhimurium bacteria after 24 hours of incubation.