Preparation and Laser Ablation Test of Vacuum Plasma Sprayed Boron Carbide Coatings

Boron carbide coatings were deposited onto stainless steel via vacuum plasma spraying (VPS), and then their phase composition, microstructure, deposition efficiency, bonding strength and laser irradiation resistance were examined. Results obtained show that there is no distinct B2O3 in the VPS B4C coating, indicating that the oxidation of B4C can be avoided during VPS process. The denser B4C coating can be obtained by using the finer original powder. Deposition efficiencies and bonding strengths of coatings are higher in the cases of higher spray power and higher H2 flow due to the better melting condition of powders during spray process. Under appropriate spray parameters, the deposition efficiency and bonding strength of VPS B4C coating can be high to 72% and 49MPa respectively. Laser ablation test shows that the laser irradiation resistance is improved significantly for stainless steel after being deposited by B4C coating.