Tribological Properties of Plasma Sprayed Al2O3–Cr2O3 Composite Coatings

Al₂O₃, Al₂O₃–Cr₂O₃ and Cr₂O₃ coatings were produced by atmospheric plasma spraying. The wear and friction properties of the coatings were evaluated under different degrees of severity by a block-on-ring arrangement. The morphologies and elemental distributions of the worn surfaces were characterized by means of electron probe microanalyzer and energy-dispersive spectrometer. It was found that the wear resistance of the Al₂O₃–Cr₂O₃ composite coating was superior to that of the pure Al₂O₃ and Cr₂O₃ coatings. The improvement in wear resistance of the Al₂O₃–Cr₂O₃ composite coatings should be attributed to their better thermal conductivities and comprehensive mechanical properties. Furthermore, the corresponding wear mechanisms were investigated.