Microstructure and properties of Ni20Cr-MoS2 composite coating by subsonic flame spraying

In this study, a Ni20Cr-MoS2 composite coating was fabricated using subsonic flame-spraying technology, and the effects of adding MoS2 on the microstructure, mechanical properties, and tribological properties of the coating were studied. The microstructure analysis of the coatings revealed that the Ni20Cr and Ni20Cr-MoS2 coatings prepared by subsonic flame spraying had fewer microscopic defects and significant particle flattening. After the addition of MoS2, the porosity of the coating decreased, whereas its microhardness increased. The cohesive strength of the coating was measured using the scratch method, and it was found to be enhanced after the addition of MoS2. Moreover, in the dry friction state, compared with the Ni20Cr coating, the Ni20Cr-MoS2 coating performs better. At a load of 20 N, the friction and wear performances of the Ni20Cr-MoS2 coating were the best, and the friction coefficient decreased by 11.63 %. Based on this, the relationships between the cohesive strength and tribological properties and between the wear mechanism and scratch mechanism of the coating are discussed.