Original Article

Study of the physical properties of Yb₂O₃-doped Gd₂Zr₂O₇ ceramics as a thermal barrier coating material

School of Materials Science and Engineering, North China University of Water Resources and Electric Power, 450000, PR China

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Received: 7 April 2025
Accepted: 25 October 2025

Abstract

Driven by the need for high-performance thermal barrier coatings (TBCs) in geothermal power generation, (Gd_xYb_1-x)₂Zr₂O₇ ceramics (x = 0.5, 0.7, 0.9, 1) were synthesized via the solid-state reaction method. Their crystal structure (XRD), microstructure (SEM), mechanical properties (hardness, fracture toughness, Young's modulus), and thermal properties (diffusivity, conductivity) were systematically characterized to investigate the impact of Yb³⁺ doping. Major findings include: (1) All compositions exhibit a stable fluorite structure from room temperature to 873 K. (2) Yb³⁺ doping significantly reduces thermal conductivity, with the x = 0.7 composition achieving the minimum value of 0.858 W · m⁻¹· K⁻¹ at 675 K (>30% lower than YSZ). (3) Doping enhances hardness and fracture toughness, peaking at 10.1 GPa and 2.23 MPa · m^1/2 for the x = 0.5 composition. (4) Young's modulus shows a non-monotonic trend with doping. This work demonstrates that Yb³⁺-doped Gd₂Zr₂O₇, particularly the x = 0.7 composition with ultralow thermal conductivity and sufficient mechanical strength, presents a promising candidate material for medium-high temperature (300–873 K) TBCs in geothermal applications, offering new avenues for durable coating design.