Effect of Cr content on microstructure and properties of Ni-Ti-xCr coatings by laser cladding

The alloy coatings were manufactured by laser cladding on Q235 mild steel. Coatings with different Cr content consisted of different phases but contains common phases Cr, Cr2Ti and NiTi. With different Cr content, the microstructure of coating with 15% Cr (15-Coating) was different from that of coating with 30% Cr (30-Coating) and coating with 45% Cr (45-Coating), while that of 30-Coaintng and 45-Coating was similar. The hardness of coatings were significantly increased in comparison with that of substrate, and the maximum micro-hardness of coatings was more than 4 times as high as substrate. The wear resistance of coatings were improved dramatically compared with the substrate. With increase of Cr content, the hardness and wear resistance of coatings were both reduced.