Thermal diffusivity of RE₂Zr₂O₇ - Type ceramic powders intended for TBCs deposited by APS

Purpose: The aim of this paper is to provide overall characteristics of the Laser-Flash method and to determine the thermal diffusivity of powders intended for thermal spraying of thermal barrier coatings (TBC) of new type by air plasma spray (APS). Lanthanum, samarium, neodymium and gadolinium zirconates based powders with a pyrochlore structure and a general formula RE₂Zr₂O₇ were used as the research material. Design/methodology/approach: The scope of the study encompassed thermal diffusivity tests of zirconium powders with the laser-flash method using the Netzsch LFA 427 apparatus for direct measurement of diffusivity. The scope of measured temperature ranged from 25°C to 1000 °C (25, 250, 500, 750 and 1000°C). Every measurement point was repeated three times in order to obtain an average value. Findings: The studies conducted have enabled determining the value of thermal diffusivity of the material analyzed in the form of powder within a wide range of temperature. Research limitations/implications: The studies conducted suggest the necessity for verification of the obtained results for analogical coatings of the TBC type in order to determine the influence of the spraying process on the thermal diffusivity of the powders examined. Practical implications: The research results obtained provide a basis for further research on the base material and in particular, on the influence of porosity on thermal diffusivity. Originality/value: The original value presented in the paper is the information regarding the new type of ceramic materials intended for thermal spraying of TBCs.