Synthesis process parameter control and performance of nano ceramic coatings for diesel engine applications

Abstract

Ceramics are non-metallic inorganic solids which are used in various forms (bulk and newlinecoatings) and environments (low and high temperature) to provide protection from newlinethermal, wear or chemical attack. Due to their high melting point, compressive newlinestrength, oxidation and corrosion resistant properties, ceramics are strong, hard, newlinebrittle and harsh environment resistant. Ceramic coatings are generally applied on newlinemetal components to either enhance their life or augment the performance of the devices they are mounted on. Furthermore, coatings being thin (few small units to hundreds of microns); they do not demand significant alteration in component design. Among the many types of coatings used in engineering applications, Thermal Barrier Coatings (TBC) and wear resistant coatings (WRC) are used to protect metallic components from thermal and mechanical damages respectively. 6 to 8%Yttria stabilized zirconia (6-8% Y2O3-ZrO2), generally designated as 8YSZ has been newlineextensively used as TBC and alpha alumina (and#945;-Al2O3) find applications as WRC. 250 to 300µm thick micron grained TBC, with grain sizes typically up to 20 µm or even higher are well known to thermally insulate diesel engine combustion chamber to provide enhanced fuel efficiency characteristics. 8YSZ and and#945;-Al2O3 coatings also find use in power plants, textiles, automotive and aero-space industries etc. to provide benefits like improved product quality and energy efficiency, extended wear life, reduced maintenance cycles and costs etc. Among ceramic coatings, nanostructured coatings have received further interest because of their extraordinary properties including enhanced hardness, strength, ductility, and toughness when compared with coatings with micron grained newlinemicrostructure. Nanostructured zirconia is also expected to serve as advanced TBC in newlineengine applications, although information on its feasibility and the technology is mostly classified.