High‐temperature mechanical and thermal properties of Ca_1−xSr_xZrO₃solid solutions

Abstract

Perovskite oxides are promising thermal barrier coatings (TBCs) materials but their thermophysical properties still need to be further improved before commercial applications. In this work, mechanical/thermal properties of calcium‐strontium zirconate solid solutions (Ca1−xSrxZrO3) are investigated. Comparing to the end‐compounds CaZrO3 and SrZrO3, the solid solutions achieve the enhanced thermal expansion coefficient, decreased thermal conductivity as well as good high‐temperature mechanical properties. The experimental thermal conductivities of Ca1−xSrxZrO3 (x = 0.2, 0.4, 0.6, 0.8) are in the range of 1.76‐1.94 W·(m·K)−1 at 1073 K, being lower than that of the yttria‐stabilized zirconia (YSZ). At the same time, their thermal expansion coefficients (10.75 × 10−6‐11.23 × 10−6/K at 1473 K) are comparable to that of YSZ. Moreover, the Young's moduli of Ca0.8Sr0.2ZrO3, Ca0.6Sr0.4ZrO3, Ca0.4Sr0.6ZrO3, and Ca0.2Sr0.8ZrO3 at 1473 K are 70.7%, 69.4%, 68.8%, and 71.1% of the corresponding values at room temperature, respectively. The good high‐temperature mechanical and thermal properties ensure the potential applications of Ca1−xSrxZrO3 solid solutions as high‐temperature thermal insulation materials including TBCs.

Ferroelastic rare‐earth tantalates for multifunctional thermal/environmental barrier coatings: A perspective

“…Figure 5 and Table 1 show the comparisons of TECs and thermal conductivities of various dense ceramics. 4,7,9,13,19,21,43,46,47,54,[71][72][73][74][75][76][77][78][79][80][81] The TECs of RETaO 4 range from 5.1 × 10 −6 K −1 to 10.7 × 10 −6 K −1 at 1200 • C. It is obvious that the TECs of RETaO 4 are similar to those of the CMC and alloy substrates, which helps reduce the thermal stress between the ceramic T/EBCs and the substrates. RETaO 4 exhibit the lowest thermal conductivity of approximately 1.4 W⋅m −1 ⋅K −1 at 900 • C, indicating their excellent thermal insulation capacities.…”

“…Therefore, F I G U R E 5 Thermal conductivity and thermal expansion coefficients (TECs) of rare-earth tantalates (RETaO 4 , RE 3 TaO 7 , and RETa 3 O 9 ) dense bulks compared with other ceramic thermal/environmental barrier coatings (T/EBCs) materials. 4,7,9,13,19,21,43,46,47,54,[71][72][73][74][75][76][77][78][79][80][81] the interface between the BC and YTaO 4 coatings was well-defined and the bonding strength exceeded 30 MPa. During high-temperature conditions, T/EBCs may spall owing to the growth and thickening of the TGO.…”

“…Figure 5 and Table 1 show the comparisons of TECs and thermal conductivities of various dense ceramics 4,7,9,13,19,21,43,46,47,54,71–81 . The TECs of RETaO 4 range from 5.1 × 10 −6 K −1 to 10.7 × 10 −6 K −1 at 1200°C.…”

“…Thermal conductivity and thermal expansion coefficients (TECs) of rare‐earth tantalates (RETaO 4 , RE 3 TaO 7 , and RETa 3 O 9 ) dense bulks compared with other ceramic thermal/environmental barrier coatings (T/EBCs) materials 4,7,9,13,19,21,43,46,47,54,71–81 …”

Crystal structure dependence of the microstructure and microwave dielectric properties of (SrxCa1−x)(Zr0.95Ti0.05)O3 (0 ≤ x ≤ 1) perovskite ceramics

“…have been widely investigated in many fields such as matrix materials 16 and thermal barrier coating. 17 Due to the low dielectric loss, simple preparation process, and low raw material price of CaZrO 3 ( ε r = 30, Q × f = 26 400 GHz, and τ f = −27 ppm °C −1 ) and SrZrO 3 ( ε r = 30, Q × f = 13 600 GHz, and τ f = −60 ppm °C −1 ), 18 investigators began to explore their application in the microwave dielectric ceramics field. C. S. Prasanth et al 19 prepared CaZrO 3 nanoparticles using a combustion method and obtained samples with a high density and high microwave dielectric properties by sintering.…”