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Ta/W/Sn multilayer coatings were made on LY12 aluminium substrate by plasma spray. Effect of various parameters on the melting degree and deposition efficiency of feedstock has been investigated.The surface and the interfaces morphology of the multilayer coatings were observed using scanning electron microscopy. The weight gain of the coatings was weighed using precision mechanical balance.The tensile strength of the multilayer was determinated by mechnical testing machine. The chemical composition of these coatings was seperately obtained using auger energy spectrum and chemical analysis.The result shows that Ta/W/Sn multilayer coatings with fine structure and uniform thickness could be prepared by plasma spray processes.The degree of the powders melting is much affected by spray power and spray rate,and does not vary much with spray distance within the specific range.