Sintering, thermal expansion, and thermal transport properties of A4Ta2O9 (A= Ca, Mg) tantalates. Issue 16 (15th August 2022)

• Record Type: Journal Article
• Authors: Luo, Keren; Chen, Lin; Li, Baihui; Lv, Liang; Wang, Yuncheng; Ji, Xiaolan; Yun, Haitao; Feng, Jing
• Is Part Of: Ceramics international. Volume 48:Issue 16(2022)
• Page Start: 23397
• Page End: 23403
• Publication Date: 2022-08-15
• Subjects: TBCs -- Tantalates -- Ceramics sintering -- Phase stability -- Thermal conductivity; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2022.04.331
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Searching for new oxides with low thermal conductivity and high thermal expansion coefficients (TECs) as thermal barrier coatings (TBCs) is vital for the development of highly efficient gas turbines and aeroengines. We report the densification sintering, high TECs, and low thermal conductivity of A 4 Ta2 O9 ( A = Ca, Mg) tantalates. The best sintering temperature of dense A 4 Ta2 O9 ceramics was determined via an optical contact angle tester, and samples with a relative density of 99.8% were synthesized via spark plasma sintering (SPS). The hardness (9–10 GPa), Young's modulus (172.7–211.8 GPa) and fracture toughness (1.5–1.6 MPa m 1/2 ) of the A 4 Ta2 O9 ceramics are primarily affected by the bonding strength. Furthermore, we studied the thermal transport properties of A 4 Ta2 O9 . The low thermal conductivity (1.78–1.93 W m −1 K −1 at 900 °C), extraordinary phase stability, and high TECs (11.4–11.8 × 10 −6 K −1 at 1200 °C) of A 4 Ta2 O9 ceramics make them candidate TBCs with high operating temperatures.