Methods to Reduce Thermal Conductivity Further of Plasma Sprayed Thermal Barrier Coatings

This paper reviews the theory of thermal conduction of ceramic materials with the aim to reduce further the thermal conductivity of plasma sprayed thermal barrier coatings. Methods of reducing thermal conductivity of plasma sprayed thermal barrier coatings including seeking for alternative ceramic materials to 8YSZ, addition of some dopants, preparing nanostructured coating and double-ceramic-layer coating are advised. It is indicated that the combination of colouring plus nanostructured and double-ceramic-layer coating of new ceramic candidate materials of lower thermal conductivity should be an very important research direction in future.