Wear and corrosion resistance of laser cladding AISI 304 stainless steel/Al2O3 composite coatings

Laser cladding AISI 304 stainless steel coatings and 304/Al2O3 composite coatings were obtained by a CO2 laser using a way of presetting powder to improve the surface wear and corrosion resistance of 45 steel. The microstructure of the coatings was measured by a metallographic microscope, and phase composition was determined by X-ray diffraction. The wear and corrosion resistance of coatings and the substrate were evaluated on a HSR-2M high speed reciprocating friction tester and an IM-6 electrochemical workstation, respectively. The results show that the wear and corrosion resistance of the substrate can be improved by laser cladding the composite coating. Microhardness of the composite coating is about 600Hv, much higher than the substrate (210Hv) and the 304 coating (200Hv), thickness of the both coating is 900 μm; the composite coating possesses excellent wear resistance validated by the friction coefficient, worn-out appearance and wear loss; polarization curves indicate that the composite coating is easier to be corroded than laser cladding AISI 304 stainless steel coating, but much harder than the substrate.