Fabrication of Cu-MoS2 Composite Coating by Cold Spraying and Evaluation of Its Property

Molybdenum disulfide (MoS₂) is widely used for structural components in order to improve friction property. However, it is difficult to fabricate MoS₂ coatings by conventional thermal spray processes due to thermal decomposition of MoS₂ feedstock powder during spraying. In this study, copper (Cu) / MoS₂ composite coatings were fabricated by cold spray method. In order to fabricate the composite coatings, composite powders were fabricated by agglomeration method and mechanical milling (MM) with changing MoS₂ concentration and milling time. It was possible to fabricate Cu/MoS₂ composite powders both agglomeration and MM methods. However it was difficult to fabricate the coatings by cold spray with using agglomeration powders with weak bonding of each particle. Cu/MoS₂ composite coatings were successfully fabricated with using MM powders. It became clear that increase the concentration of MoS₂ in the coating decrease the friction coefficient. However, higher amount of MoS₂ decreased deposition efficiency of particles during spraying and increased abrasion loss. The ideal concentration ratio of MoS₂ particle is lower than 5wt.% upon fabrication of Cu/MoS₂ coatings by cold spray. It was possible to enhance the hardness and wear resistance of the coatings by increase the milling time of feedstock powders. Therefore, Cu/MoS₂ composite coating with good friction property can be fabricated with controlling feedstock powder.