Effect of Molybdenum Disilicide on Microstructure and Properties of Nickel-Aluminum Coating

MoSi2 was added to nickel-aluminum powders to prepare nickel-aluminum coatings by using plasma spraying,the effect of MoSi2 on microstructure,microhardness and friction and wear property of nickel-aluminum coatings was studied,and the wear mechanism of the coating was analyzed.The results show that the nickel-aluminum coating mainly composed of Ni3Al,NiAl,MoSi2 and Mo5Si3 phases after adding MoSi2,the number and size of porosity and the microcracks in the coating and the microhardness of coating increased with the increase of the content of MoSi2.The wear resistance of the coating with 20wt% MoSi2 was the best.The wear mechanism of pure nickel-aluminum coating was ploughing caused by abrasive particles,the wear mechanism of the coating with 20wt% MoSi2 was mainly pressing and a small number brittle fracture,and the wear mechanism of the coating with 50wt% MoSi2 was brittle fracture.