An Experimental and Numerical Algorithm for near Net Shape Forming of Thin Walled Ceramic Structures by Plasma Spraying

Near Net Shape (NNS) forming by plasma spraying is a novel manufacturing technique to develop free standing part of ceramics and those materials which are difficult to manufacture by conventional techniques. A few studies found in the literature have reported successful fabrication of near net shaped free-standing parts such as rocket nozzles and propulsion components. But these studies seem to be empirical in nature as none has reported manufacturing protocol based on thermal analysis and heat transfer between substrate, coating, and surrounding, which is extremely critical for NNS forming.  In this effort, we have attempted to develop a numerical and experimental algorithm to improve predictability in near net shape forming by plasma spraying. In order to do this thermal analysis of the substrate is carried out to estimate temperature profile and relative thermal stresses induced during spraying and after spraying for different substrate material and geometry for Al₂O₃ coating.  It is anticipated that this algorithm can be applied to predict the removability of the ceramic component for a given combination of coating and substrate material.