Statistical analysis of wear and friction behavior on plasma sprayed Nano Al₂O₃ - TiO₂ - AISI 1020 steel coatings using definitive screening design

The primary objective of the present investigation is to study the tribological characteristics of AISI 1020 steel coated with varied weight percentages at Nano levels of Al₂O₃ (2, 3 and 4 wt%) and a fixed 2 wt% of TiO₂. Al₂O₃ and TiO₂ powders were sprayed using a plasma spray technique over the surface of mild steel. The input factors are weight% of Al₂O₃, time, load, sliding velocity and sliding distance relative to the responses such as wear loss and coefficient of friction. Experimentation was conducted across 13 trials utilizing Definitive Screening Design (DSD). Scanning electron microscopy with energy dispersive spectroscopy, atomic force microscopy, x-ray diffraction was employed to examine the worn-out morphology of the coated surface. Irrespective of other input factors, coated specimen with 4 wt% of Al₂O₃ and 2 wt% of TiO₂ exhibited the minimum wear loss and specimen with 2 wt% of Al₂O₃ and TiO₂ showed lower coefficient of friction. The optimization graph of statistical analysis revealed 2.95 mg of wear loss and 0.028 of coefficient of friction as the optimal responses corresponding to the input factors Al₂O₃ of ~ 4 wt%, time of ~ 45 min, load of 20 N, sliding velocity of ~ 1 m/s and ~ 692 m sliding distance, respectively. The consistency prevails between predicted and actual responses.