Thermal barrier coatings (TBCs) are ceramic coatings with a good thermal barrier effect at high temperatures, and have some important applications in the thermal protection of gas turbines, internal combustion engines, rocket engines and other high-temperature environments. Zirconia stabilized by rare-earth or alkaline earth oxides are used for nearly 60 a, and yttria stabilized zirconia (YSZ) is the mostly used material. Since last two decades, many materials are developed, i.e., nano-YSZ, rare earth zirconates, rare-earth aluminates, rare-earth tantanates, alkaline earth zirconates, etc.. New TBC materials have lower thermal conductivities, better sintering resistances and similar or larger thermal expansion coefficients, but much lower fracture toughness, more complicated compositions and therefore much shorter thermal cycling life rather than YSZ. In order to improve the durability of the TBC materials for high-temperature applications, the coating deposition process should be controlled effectively to keep a stoichiometric composition and the double-ceramic-layer (DCL) coatings could be applied.

thermal barrier coatings  /  rare earths  /  zirconia  /  zirconate  /  aluminate