Abstract
Ceramic oxide coatings were made with a unique microstructure using solution plasma spray (“SPS”), a novel variant on the conventional powder plasma spray techniques. In the SPS process, a precursor solution is fed into an air plasma torch using a liquid injector, and a nanocrystalline ceramic coating is formed directly on various substrates without post heat treatment. It was found that the microstructure of the SPS coating depended on control of process parameters for liquid feed and plasma spray to a large extent. This study deals with the formation of SPS deposited yttria stabilized zirconia coatings with a well-controlled microstructure addressing porosity, cracking and adhesion. The SPS-deposited YSZ coatings have demonstrated unique microstructural characteristics including adjustable porosity, vertical microcracks and the absence of splat boundaries. Such zirconia-base coatings show great potential for the applications of high-density electrolyte layers in solid oxide fuel cells (“SOFC”s) and high porosity/low conductivity thermal barrier coatings for industrial and gas turbines.
