Microhardness and wear resistance of Al2O3-TiB2-TiC ceramic coatings on carbon steel fabricated by laser cladding

Al₂O₃-TiB₂-TiC ceramic coatings with high microhardness and wear resistance were fabricated on the surfaces of carbon steel substrates by laser cladding using different coating formulations. The microstructures of these ceramic coatings with the different coating formulations were investigated using X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometer. The wear resistance and wear mechanism were analyzed using Vickers microhardness and sliding wear tests. The results showed that when the amount of independent Al₂O₃ was increased to 30%, the ceramic coatings had a favorable surface formation quality and strong metallurgical bond with the steel matrix. The cladding layer was uniformly and densely organized. The black massive Al₂O₃, white granular TiB₂, and TiC distributed on the Fe substrate significantly increased the microhardness and wear resistance. The laser cladding ceramic coating had many hard strengthening phases, and thus resisted the extrusion of rigid particles in frictional contact parts. Therefore, the wear process ended with a “cutting-off” loss mechanism.