Study on Preparation of Aluminum Ash Coating Based on Plasma Spray

Ultimate aluminum ash (UAA) was used as the key raw material to prepare ultimate spray powder (USP) via water hydrolysis and ball milling, after which the coating was prepared by atmospheric plasma spray. The flowability of the USP was evaluated by the angle of repose; the process parameters of the coating were determined by orthogonal experiment, and the microstructure and properties of the coating were characterized. The results show that the ultimate spray powder after granulation has an angle of repose less than 40°, which meets the requirements of plasma spray. When the spray current is 600 A, the spray voltage is 55 V, the powder flow rate is 22 g/min, and the main air flow is 33 lspm, the prepared ultimate coating has the best comprehensive performance. The microhardness of the coating is 512 HV, which is about 1.5 times the hardness of the substrate; the abrasion rate is 18.53 × 10−3 g/min; the porosity is 0.17% and the average adhesive strength is 8.78 Mpa, which confirms the feasibility of using aluminum ash as a spray powder to prepare a coating.