An Experimental Investigation into the Amalgamated Al<sub>2</sub>O<sub>3</sub>-40% TiO<sub>2</sub> Atmospheric Plasma Spray Coating Process on EN24 Substrate and Parameter Optimization Using TLBO

Abstract

Surface coating is a critical procedure in the case of maintenance engineering. Ceramic coating of the wear areas is of the best practice which substantially enhances the Mean Time between Failure (MTBF). EN24 is a commercial grade alloy which is used for various industrial applications like sleeves, nuts, bolts, shafts, etc. EN24 is having comparatively low corrosion resistance, and ceramic coating of the wear and corroding areas of such parts is a best followed practice which highly improves the frequent failures. The coating quality mainly depends on the coating thickness, surface roughness and coating hardness which finally decides the operability. This paper describes an experimental investigation to effectively optimize the Atmospheric Plasma Spray process input parameters of Al2O3-40% TiO2 coatings to get the best quality of coating on EN24 alloy steel substrate. The experiments are conducted with an Orthogonal Array (OA) design of experiments (DoE). In the current experiment, critical input parameters are considered and some of the vital output parameters are monitored accordingly and separate mathematical models are generated using regression analysis. The Analytic Hierarchy Process (AHP) method is used to generate weights for the individual objective functions and based on that, a combined objective function is made. An advanced optimization method, Teaching-Learning-Based Optimization algorithm (TLBO), is practically utilized to the combined objective function to optimize the values of input parameters to get the best output parameters. Confirmation tests are also conducted and their output results are compared with predicted values obtained through mathematical models. The dominating effects of Al2O3-40% TiO2 spray parameters on output parameters: surface rough

Effects of 316SS addition on the properties of the coatings based on Al2O3 applied by plasma spraying

“…The injected powder will undergo heat treatment that affects the morphology of the deposit, its features, and performances. The more significant parameters are the hydrogen in the gas plasma mixture, 11,12 the power of the torch, 13,14 the roughness and the temperature of the substrate, 15,16 the size of the powders, 13 the projection distance, 4,13,16 and the penetration of particles in the plasma jet. The lack of control over these parameters in each step of the process leads to structural defects such as porosity, poorly melted particles, microcracking, reduced adhesion, and in some cases detachment of the substrate.…”

“…Therefore, ceramic coatings and especially those with Al 2 O 3 matrix are increasingly used in these applications that require high hardness, good tribological properties, and excellent corrosion resistance. 1,2 Ceramic mixed formulations such as Al 2 O 3 -TiO 2 coating are extensively used 3,4 for their wear and corrosion resistance 5 as well as high bond strength. 6,7 Different techniques could be employed in ceramic coating development, for example electro-deposition, micro-arc oxidation, laser cladding, and thermal spraying.…”