Novel ceramic coatings reportedly break thermal performance barrier
The thermal barrier coatings could shield gas turbines and aircraft engines at 1,200-1,500oC, say researchers in China.
The tantalate high-entropy ceramic (HEC) coatings have been synthesised onto nickel-based alloy substrates using air plasma spraying (APS) at the Kunming University of Science and Technology in China.
The novel tantalate HEC coatings are found to work at up to 1,500oC.
The team says APS promotes the complete dissolution of Yb3+, Y3+, Ta5+, and Nb5+ cations into ZrO2 lattices, yielding single-phase fluorite ceramic coatings that are ~150μm thick with a bond coat of 120μm.
The team subjected the HEC coatings to thermal shock at 1,500°C for 614 cycles, thermal fatigue at 1,150°C for 12,830 cycles and isothermal annealing at 1,100°C for 384 hours. They claim their coatings maintain excellent structural integrity and a stable fluorite crystal structure in each case.
