Effects of Nb⁵⁺ doping on thermal properties of Gd₂(Zr_1−xNb_x)₂O_7+x ceramics

ABSTRACT

Pyrochlore Gd₂(Zr_1−xNb_x)₂O_7+x (x = 0, 0.05, 0.1, 0.15) ceramic materials were synthesised using a high-temperature solid-state reaction method. The phase structure, thermal expansion coefficient and thermal conductivity of Gd₂(Zr_1−xNb_x)₂O_7+x were investigated in this work. The results show that with the introduction of Nb₂O₅, Gd₂(Zr_1−xNb_x)₂O_7+x ceramic materials present a cubic pyrochlore structure. Meanwhile, Gd₂(Zr_1−xNb_x)₂O_7+x ceramics have clear grain boundaries. The thermal expansion coefficient of Gd₂(Zr_1−xNb_x)₂O_7+x ceramic materials reduces from 11.4576 × 10⁻⁶ to 10.7919 × 10⁻⁶ K⁻¹ (larger than 10 × 10⁻⁶ K⁻¹), while its thermal conductivity gradually increases with the doping of Nb⁵⁺ ions. Considering their comprehensive properties, Gd₂(Zr_1−xNb_x)₂O_7+x compounds may be considered as promising thermal barrier coatings materials.

KEYWORDS:

• Gd₂Zr₂O₇
• Nb₂O₅ doping
• thermal properties
• pyrochlore

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [51762036].