APPLICATION OF HVOF TECHNIQUES FOR SPRAYING OF CERAMIC COATINGS

摘要

HVOF sprayed ceramic coatings can be considered as potential candidates for applications, where good chemical and corrosion resistance of ceramics is needed. Due to the less porous structure of the HVOF sprayed coating as compared to the plasma sprayed one, the protection capability of the coating is increased. However, because of the relatively low temperature of the HVOF flame, the spray process must be carefully optimized in order to produce coating with a sufficient melting state and good lamella adhesion. In this paper the process mapping tool is presented in order to optimize the HVOF spray process for ceramics. Effect of coating microstructure on the coating properties of various ceramic coatings such as alumina, chromia and zirconia is described. Abrasive wear rate, hardness and elastic properties are determined in order to reveal the effect of the spray system and nanostructured spray powders on the coating performance. Correlation of the coating microstructure with the coating performance is discussed. It is shown that HVOF spraying of ceramics can be an effective method to produce dense, well-adhered ceramic coatings with good environmental protection capability.