Ti-Al composite coating prepared by laser cladding on steel surface

In order to improve the microhardness and corrosion resistance of Q235 steel, Ti-Al intermetallic compound composite coating were prepared on Q235 steel surface by using laser cladding with the addition of mechanical milled Ti, Al powder. The microstructure of Ti-Al composite coating was analyzed using DTA, XRD and SEM, while the microhardness and corrosion resistance of the cladding layers were measured. The results showed that Ti-Al mixed powders can be refined by milling. Metallurgical bonding was formed between the base metal and the cladded coating which were composed of Al₃Fe, Al₃Ti, Fe, AlN and FeO. The microhardness of the cladded layer was high and corrosion resistance was excellent. When the laser power was 1 000 W and scanning speed was 600 mm/min, the highest microhardness of the coating reached at 949.5 HV, and the corrosion resistance impedance could be 600 kΩ,.