Denser Ceramic Coatings Obtained by the Optimization of the Suspension Plasma Spraying Technique

Abstract

The innovative suspension plasma spraying (SPS) technique, in which the carrier gas used to inject particles (10…100 µm) into the plasma jet is replaced by a liquid feedstock, is currently under development procuring denser ceramic coatings due to the use of submicron particles. The suspension properties, as well as the most relevant injection parameters - injection angle and liquid velocity - are adjusted to improve the coating quality at acceptable deposition rates. In addition, the plasma jet instabilities are studied and correlated to the coating properties. In the present work, a feasibility study is conducted addressing the key factors influencing the coating morphological properties such as the porosity, cracks, molten-fraction and amount of over-spray. The experimental setup is adapted to different DC plasma torch architectures (Sulzer-Metco F4 and Triplex) operating under atmospheric conditions with the aim of correlating the plasma jet qualities to the properties of the feedstock under consideration. The metallographic probes and fractured surfaces of the resulting yttria stabilized zirconia (YSZ, 5 wt. % Y2O3) coatings are analyzed by means of light microscopy and scanning electron microscopy (SEM).

Methane Reforming Deposit by Suspension Plasma Spraying

“…The anode is made by a non conventional method, the suspension plasma spraying (SPS). Thermal spaying is a non usual technique to produce SOFC but we could found in the scientific literature some laboratories working on [3,4]. Anode fabrication by SPS is presented in the first paragraph of this article.…”