Tailoring the initial characterization of fully stabilized HfO2 with Y2O3/Ta2O5

New ceramic materials for thermal barrier coating (TBC) are a key to more powerful and efficient next-generation gas turbines. Here, we investigate the effect of the two novel dopants, Ta2O5 and Y2O3, on the phase stability, thermophysical and mechanical properties of the HfO2-based ceramic systems (i.e., Ta2O5-HfO2; Y2O3-HfO2). For the Ta2O5-HfO2 system, we observe the formation of a new compound, Hf6Ta2O17. In the Y2O3-HfO2 system, stabilized HfO2 with up to 18 mol% YO1.5 (YSH) is generated, whereby monoclinic HfO2 transforms to cubic HfO2. The cubic YSH ceramics demonstrate enhanced phase stability, compared with Hf6Ta2O17 at temperatures up to 1300 degrees C. The mechanical properties, thermal expansion and fracture toughness of 18-24 mol% YSH (YO1.5 = 18-24 mol%) indicate that cubic YSH exhibits enhanced suitability for higher-temperature. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The research on the effects of novel dopants Ta2O5 and Y2O3 on ceramic systems has led to the discovery of new compounds Hf6Ta2O17 and stabilized HfO2 with 18 mol% YO1.5 (YSH). It has been found that cubic YSH ceramics exhibit enhanced phase stability and mechanical properties at high temperatures.