Влияние термообработки на теплопроводность монокристаллов твердых растворов на основе ZrO-=SUB=-2-=/SUB=-, стабилизированных оксидами скандия и иттрия

Abstract

The effect of heat treatment at 1000° C for 400 hours on the thermal conductivity of crystals stabilized with scandium oxide, (ZrO2)1-x(Sc2O3)x (x = 0.08–0.10), and together with scandium and yttrium oxides, (ZrO2)1-x-y(Sc2O3)x(Y2O3)y (x = 0.003−0.20; y = 0.02−0.025). For crystals of zirconium dioxide stabilized with scandium oxide, the most noticeable changes in thermal conductivity concern 9ScSZ crystals, in which changes in the phase composition occur, and a noticeable amount of rhombohedral phase appears. For 8ScSZ crystals, these changes are less noticeable and are mainly caused by the ordering of oxygen vacancies and changes in the microstructure of the samples, while for 10ScSZ crystals they are practically absent. The 10ScSZ crystals have the minimum electrical conductivity, both before and after annealing, which is determined by the highest content of scandium oxide in the solid solution. Small changes in thermal conductivity concern crystals of partially stabilized zirconia codoped with scandium and yttrium oxides. For cubic crystals 8Sc2YSZ and 10Sc2YSZ, there are practically no changes in the value of thermal conductivity, the nature of the temperature dependence of thermal conductivity, and the phase composition of crystals. The introduction of yttrium oxide into solid solutions based on zirconium dioxide along with scandium oxide makes it possible to increase the stability of its phase composition and structurally dependent thermal and electrophysical characteristics.