The effect of annealing on the properties of electroless MgB2 film on deposited AZ91 magnesium alloy

Due to its high specific strength and castability, AZ91 Mg alloy is the most produced magnesium alloy in the industry. However, AZ91 alloy is required to coat the surface due to limited wear and corrosion resistance. Many coating processes are applied to improve the properties of these alloys. Electroless coating method is preferred due to its advantages such as the coating of materials having multiple and different geometrical structures at the same time and not to be needed electrical apparatus. In this study, MgB2 coating was deposited on the surface activated AZ91 substrate material by electroless plating method at 95°C bath temperature and for 60 min. Then the produced MgB2 coatings were annealed at 300°C and 60 min. Before and after deposition, the structural properties, the hardness pecularities, friction properties and wettability of MgB2 coatings were investigated XRD, SEM, Vickers microhardness indenter, pin-on-disc tribotester and contact angle meter, respectively. As a result of these analyzes, it was observed that the coatings were dense and nodular. The highest hardness was obtained from the annealed coatings at a value of 500 HV0.01 while the MgB2-coated and the annealed films after deposition exhibited (101) orientation. It was also found that the MgB2 coatings had a superhydrophilic surface. Keywords: AZ91, MgB2, Electroless Deposition, Annealing, Wettability