Low thermal conductivity Y₂Ti₂O₇ as a candidate material for thermal/environmental barrier coatings

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• 作者：Son Thanh Nguyen^a ; ^{thanhson@etigo.nagaokaut.ac.jp" class="auth_mail" title="E-mail the corresponding author} ; Tadachika Nakayama^a ; ^{nky15@vos.nagaokaut.ac.jp" class="auth_mail" title="E-mail the corresponding author} ; Hisayuki Suematsu^a ; Tsuneo Suzuki^a ; Masatoshi Takeda^b ; Koichi Niihara^a
• 关键词：B. Composites ; C. Mechanical properties ; D. TiO2 ; D. Y2O3 ; Thermal/environmental barrier coatings
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：42
• 期：9
• 页码：11314-11323
• 全文大小：3793 K

文摘

Ceramic matrix composites of yttrium titanate (Y₂Ti₂O₇) with nickel (Ni) or silicon carbide (SiC) were synthesized to investigate their potential as candidate materials for thermal/environmental barrier coatings. The composites were sintered by hot-pressing at 25 MPa. The mechanical properties of the composites including bulk density, Vickers hardness, and fracture toughness were evaluated. The measurements indicated that the incorporation of Ni or SiC has a positive effect in terms of enhancing the fracture toughness of the composites. Microstructural observations revealed that Y₂Ti₂O₇/Ni is an inter/intra nanocomposite, while Y₂Ti₂O₇/SiC has characteristics of a network microstructure composite. In addition, X-ray diffraction and energy dispersive X-ray spectroscopy analyses confirmed Y₂Ti₂O₇ was chemically stable against Ni, but reacted with SiC to form silicates during the sintering process. The mechanisms for these reactions are also proposed.