Corrosion and wear resistance of TiN/TiO2 composite ceramic coatings deposited by supersonic arc spraying

TiN/TiO2 composite ceramics coatings have been deposited on the surface of Q345B structural steel using supersonic dual-filament arc spraying. The structural, mechanical, wear resistance and corrosion resistance properties of TiN/TiO2 composite ceramics coatings were systematically analyzed using various characterization techniques. The physical and chemical compositions, surface morphology, Young's modulus and hardness of the coatings were analyzed using XRD, XPS, SEM, EDS and nanoindentation. The corrosion resistance properties of the coatings were evaluated using potentiodynamic polarization tests in a 3.5 wt% NaCl solution. The wear condition and specific wear rate of linear reciprocating friction of the coatings and Q345B against GCr15 steel balls at different normal loads of 5 N and 10 N and in a 3.5 wt% NaCl corrosive solution environment were investigated using a Rtec-multifunctional friction machine. The wear surface and wear mechanism were also analyzed. The results show that the coating thickness is approximately 300 μm, the internal structure is uniform and dense, and the overall porosity is low, exhibiting a certain laminar structure. The coating exhibits extremely high hardness and high Young's modulus of 26.3 GPa and 264.3 GPa, respectively, with a 10.2-fold increase in hardness over the substrate. The corrosion current of the coatings decreased by three orders of magnitude compared to the substrate, with higher polarization resistance and charge transfer resistance. In wear tests under different conditions, the coatings exhibit perfect wear resistance characteristics, with a specific wear rate of only 5.19%–14.48% of the substrate specific wear rate.