Microstructure and friction-wear performances of laser-cladded nano-CeO2-reinforced NiCoCrAlY coatings at high temperature

摘要

Nano-CeO2-reinforced NiCoCrAlY coatings were fabricated on Ti6Al4V alloy using laser cladding. The morphologies, chemical compositions, and phases of obtained coatings were analyzed using a scanning electron microscope, energy-dispersive spectrometer, and X-ray diffraction, respectively, and the effects of nano-CeO(2)mass fraction on the coefficient of friction and the wear rate of NiCoCrAlY coating at 600 degrees C were investigated using a ball-on-disk wear test. The results show that the nano-CeO2-reinforced NiCoCrAlY coating is mainly composed of NiTi2, Ti3O, CoO, and beta-Ti phases, while the new phases of AlTi(3)and (Ni, Co)(2)Ti4O are formed after the wear test. The average coefficients of friction of NiCoCrAlY coatings with the nano-CeO(2)mass fractions of 0%, 2%, 4%, and 6% are 0.699, 0.655, 0.636, and 0.615, respectively, and the corresponding wear rates are 4.04 x 10(-7), 3.95 x 10(-7), 3.13 x 10(-7), and 2.35 x 10(-7)mm(3)N(-1)m(-1), respectively, which decrease with the increase of nano-CeO(2)mass fraction. The wear mechanism is primary adhesive wear and oxidation wear, accompanied by slight abrasive wear, and the addition of nano-CeO(2)is the main factor that is enhancing wear resistance.