ISSN 0862-5468 (Print), ISSN 1804-5847 (online) 

Ceramics-Silikáty 66, (4) 471 - 479 (2022)

Zhang Hongquan 1, Peng Zhiyong 1, Wen Jin 1, Chen Pengjie 2, Lin Fengsheng 1
1 School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, PR China
2 Jieyang Hengcheng Ceramic Technology Co. Ltd., Jieyang 522021, PR China

Keywords: Al₂TiO₅ solid solution, Low thermal expansion, Thermal shock resistance, CaO additive

Aluminium titanate (Al₂TiO₅) based ceramic materials were successfully processed through the addition of porcelain clay and different amounts of CaO to the stoichiometric alumina - titania mixtures that contain commonly used MgO and Fe₂O₃ additives at 1350-1400 ̊C for 1 h. The effect of the addition of CaO and sintering temperatures on the formation of the Al₂TiO₅ ceramics and thermal-mechanical performances were investigated. The results revealed that CaO promoted the formation of a long columnar Al₂TiO₅ solid solution and anorthite as well as gahnite phases. Due to the mismatch of the thermal expansion coefficient between the Al₂TiO₅ solid solution crystals and the anorthite and gahnite phases, a compressive residual stress developed on the surface of the Al₂TiO₅ solid solution particulates, effectively improving the mechanical properties and inhibiting the thermal decomposition of the Al₂TiO₅ solid solution and the microcrack propagation. The average thermal expansion coefficient (20-800 ̊C) of the sample with 3 wt% CaO sintered at 1400 ̊C for 60 min was 0.80×10-6 ̊C-1, and the flexural strength of the sample with 5 wt% CaO sintered at 1380 ̊C was as high as 58.59 MPa, with a 12.43 % increase in the strength after the thermal shock test.

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doi: 10.13168/cs.2022.0043
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