Experimental design of plasma-sprayed Alumina-Titania coatings using Taguchi method

ABSTRACT Atmospheric Plasma sprayed Alumina-Titania (Al2O3-3wt % TiO2) coatings were deposited onto commercial SS304 substrates. A Taguchi L9 design of experiment protocol was used to optimize the coating process parameters. The effect of three factors: spray distance, the arc current, and scan times on the coating responses was studied. The responses of the plasma sprayed coatings were evaluated in terms of porosity, adhesion Strength, and micro-hardness. The results indicated that porosity levels ranged from 8.8% to 4.8%. Less porosity occurred at higher arc currents and intermediate spray distances. While, adhesion strengths ranged from 9.65 to 11.40 MPa, peaking at higher arc currents and optimal spray distances. In addition, microhardness values ranged from 657.30 HV to 770.20 HV. The relationship between the independent variables and the product responses is fitted using the regression analysis technique. Higher arc current, lower scanning times, and a medium spray distance leading to optimum attributes of low porosity, high adhesion Strength, and high micro-hardness.