FABRICATION OF IN SITUFe-Ti-B COMPOSITE COATING BY LASER CLADDING

Abstract

Laser cladding was applied to deposit in situ Fe - Ti - B composite coatings on mild carbon steel with precursor of ferrotitanium, ferroboron and pure Fe alloy powders. The composite coatings were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron probe microanalysis (EPMA). Wear resistance of the laser-cladded Fe - Ti - B coatings was evaluated under dry sliding condition at room temperature using block-on-ring wear tester. Results indicate that in situ reinforcements of TiB 2 and Fe 2 B can be synthesized in the Fe - Ti - B coatings. The amount of TiB 2 increases with the increase of content of ferrotitanium and ferroboron in the precursor. Reinforcements are formed through the liquid-precipitation route following the solidification path of the Fe - Ti - B system. Hardness and wear properties of the coatings improved significantly in comparison to the as-received substrate due to the presence of hard reinforcements.