Tribological performances of YSZ composite coatings manufactured by suspension plasma spraying

Nanostructured coatings are more and more considered in scientific literature because of their benefit contributions in improving coating properties such as toughness, wear resistance or thermal properties. In conventional plasma spraying, agglomeration of nanometer-sized particles into micrometer-sized feedstock can be injected using a carrier gas to obtain a bimodal structure. Or, since now ten years, a liquid carrier (Suspension Plasma Spray process, SPS) is employed to drive nanometer or sub-micrometer sized particles into the plasma jet with a limited agglomeration of the particles. With SPS, the reduced microstructural size of coatings improves their tribological properties, especially for ceramic coatings. This study aims at studying yttria stabilized zirconia (YSZ) coatings manufactured by suspension plasma spraying. The primary objective of this work is to improve tribological performances of YSZ coatings, which is found to be better when a higher plasma enthalpy is used to elaborate them. The second objective is to incorporate reinforcements within the YSZ matrix to improve further performances. In that way SiC has been included in the YSZ matrix resulting in a higher wear resistance. (C) 2012 Elsevier B.V. All rights reserved.