Mechanical and thermal properties of fine-grained quasi-eutectoid (La1xYbx)2Zr2O7 ceramics》.pdfVIP

Available online at ScienceDirect Journal of the European Ceramic Society 35 (2015) 3145–3154 Mechanical and thermal properties of fine-grained quasi-eutectoid (La1−x Yb ) Zr O ceramics x 2 2 7 Xiaorui Ren a , Chunlei Wan b,∗, Meng Zhao a , Jun Yang a , Wei Pan a,∗∗ a State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science Engineering, Tsinghua University, Beijing 100084, PR China b Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603, Japan Received 29 November 2014; received in revised form 13 April 2015; accepted 20 April 2015 Available online 4 May 2015 Abstract A2B2 O -type rare earth zirconates have been intensively investigated as potential thermal barrier coating (TBC) materials due to their low thermal 7 conductivities and high stability at high temperature. In this work, mixing La3+ and Yb3+ with a large difference in atomic radii at A site formed a quasi-eutectoid mixture of La Zr O -rich pyrochlore phase and Yb Zr O -rich fluorite phase. The competition between these two phases in 2 2 7 2 2 7 grain growth effectively reduces the grain size down to 0.8–1 m, giving rise to improved mechanical properties comparing with the single-phase materials, including a higher hardness, a higher fracture toughness and a lower elastic modulus. Furthermore, a significantly low thermal conductivity was found, as the