Thermal and Dry Sliding Wear Behavior of Plasma Sprayed Red Mud-Fly Ash Coatings on Mild Steel

The present work focuses to understand the limitations towards high temperature applications of plasma sprayed coatings like pure red mud, composited with varying weight % (10, 20 and 50) of fly ash on mild steel. Spraying is done at different operating power namely 9, 12 and 15 kW. Coating characteristics like morphology, thickness and phase formations are studied. The sustainability of these coatings towards high temperature at air environment up to 1000 °C is evaluated by finding their adhesion strength. DSC and TGA techniques are implemented to observe the coating behavior to heat. The coatings show remarkable resistance towards high temperature by virtue of adhesion strength compensation. It is feasible to use these coatings <800 °C, otherwise dislodging of coating from metal. Finally sliding wear performances are seen using a pin on disc tribometer at track diameter of 100 mm, sliding speed of 100 rpm (0.523 m/s) and normal load of 10 N with 3 minute incremental time interval up to 51 minute. Sliding time is seen to be remarkable variable for wear rate. Reinforcement of fly ash leads to form stronger bond strength with mild steel. Wear experiments are designed by Taguchi optimization technique to conclude the optimum variable impacting it.