Large degradation in thermal insulation and strain tolerance is a main headache for thermal barrier coatings (TBCs). The cause is the healing of interlamellar pores formed by multiple connections between the edges of a pore. Firstly, mechanism responsible for the multiple connections was revealed. The roughening of the pore surface occurs during thermal exposure, along with grain growth inside the splats. Consequently, local surface height increases, which causes multiple connections and healing of interlamellar pores. Critical widths of interlamellar pores to avoid multiple connections during thermal exposure is established by correlating the extent of surface roughening with the growth of individual grains. Secondly, sintering-resistant TBCs were obtained by tailoring the width of interlamellar pores to avoid multiple connections. Composite TBCs were prepared to form wide interlamellar pores in the coatings. The increases in thermal conductivity and elastic modulus can be prevented to a large extent.

thermal barrier coatings