Electrodeposition and tribological properties of Ni-SrSO4 composite coatings

Ni-SrSO4 composite coatings were electrodeposited on superalloy Inconel 718 from a Watts electrolyte containing a SrSO4 suspension. Ni-SrSO4 coatings were investigated by scanning electron microscope, microhardness tester, and friction and wear tester in sliding against a bearing steel ball under unlubricated condition. The incorporation of SrSO4 into Ni matrix increases the microhardness of electrodeposited coatings. Ni-SrSO4 composite coating exhibits a distinctly low friction coefficient and a small wear rate as contrasted with pure Ni coating and the substrate. The effect of SrSO4 particles on microstructure and tribological properties of Ni-SrSO4 composite coatings is discussed.