Dry sliding wear behaviour of suspension HVOF thermal sprayed Al2O3-MoS2 and Al2O3-BN nanotube coatings

In our present work, alumina/BNNTs and alumina/MoS2 coatings were deposited onto stainless steel substrates by solution precursor high velocity oxy-fuel thermal spraying. The phase evolution, microstructure and tribological properties of the two kinds of coatings were studied. Investigation of the phased content showed that Al2O3, BN and MoS2 survived in the coatings after being sprayed with SHVOF technology. Cross-section images of the coatings showed that the interface between the coating and the substrate was well bonded, and there were no obvious particle inclusions and defects at the interface. The top morphology of the coatings exhibited certain degree of particle deformation, which was conducive to the formation of a more compact coating with less porous and better bonding strength with the substrate. Dry sliding tests showed that alumina/BNNTs and alumina/MoS2coating improved the tribological properties of the samples and they were suitable for low load friction conditions (5 and 10 N). A crack evolution model was proposed to analyze the failure of coatings. This work could provide a reference for the application of the two coatings in the field of friction and wear.