Effect of Yb2SiO5 addition on the physical and mechanical properties of sintered mullite ceramic as an environmental barrier coating material

• Published in: Ceramics international Vol. 42; no. 14; pp. 15203 - 15208
• Main Authors: Feng, Fan-Jie, Jang, Byung-Koog, Park, Ji Yeon, Lee, Kee Sung
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2016
• Subjects: Environmental barrier coatings; Mechanical properties; Mullite; Silicate; Environmental barrier coatings; Mechanical properties; Mullite; Silicate
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2016.06.149

In this study, ytterbium monosilicate (Yb2SiO5)-added sintered mullite ceramics are prepared as candidate materials for environmental barrier coatings (EBCs). The effect of adding Yb2SiO5 on the physical and mechanical properties of the sintered mullite ceramics is investigated. The Yb2O3–SiO2–Al2O3 ternary phase diagram indicates that adding Yb2SiO5 to the mullite goes beyond simply mixing; instead, liquid sintering occurs. Therefore, when we add Yb2SiO5 to the mullite, the sintered body possesses a denser microstructure and faster densification rate than does pure mullite. The density rapidly increases with the addition of 6wt% Yb2SiO5 in the mullite, and almost full densifications are achieved with the addition of 12wt% and 18wt% Yb2SiO5. In this study, mullite ceramic that contains 12wt% Yb2SiO5 exhibits the smallest plastic deformation and the highest elastic modulus among ceramics containing 6, 12, and 18wt% Yb2SiO5, according to Hertzian indentation results. The results suggest that 12wt% Yb2SiO5-doped mullite may be expected to act as a potential EBC material based on its excellent elastic properties, dense microstructure, and appropriate coefficient of thermal expansion.