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Ultra-large zirconia toughened alumina (ZTA, mass ratio of Al2O3 and ZrO2 is 78:22) ceramics with eccentric circle shape were successfully sintered by microwave sintering with a multi-mode cavity at 2.45 GHz. The dimension of ZTA ceramics (green body) is 165 mm (outer diameter) × 25 mm (thickness). The optimized sintering temperature of microwave sintering is about 1500 ℃ for 30 min, and the total sintering time is about 4 h which is much shorter than that of conventional sintering. An auxiliary-heating insulation device was designed based on the principle of local caloric compensation to guarantee the intact sintered samples. With the increasing of sintering temperature, more and more microwave energy is absorbed within the entire sample, volumetric densification performs, and phases shift from m-ZrO2 phase to t-ZrO2 phase and cause Al2O3 grain growth.


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Preparation of large size ZTA ceramics with eccentric circle shape by microwave sintering

Show Author's information Yongqiang CHENa,bBingbing FANb,c( )Gang SHAObRui ZHANGa,b( )
Zhengzhou University of Aeronautics, Henan 450015, China
School of Materials Science and Engineering, Zhengzhou University, Henan 450001, China
Sinosteel Luoyang Institute of Refractories Research Co., Ltd., Henan 471039, China

Abstract

Ultra-large zirconia toughened alumina (ZTA, mass ratio of Al2O3 and ZrO2 is 78:22) ceramics with eccentric circle shape were successfully sintered by microwave sintering with a multi-mode cavity at 2.45 GHz. The dimension of ZTA ceramics (green body) is 165 mm (outer diameter) × 25 mm (thickness). The optimized sintering temperature of microwave sintering is about 1500 ℃ for 30 min, and the total sintering time is about 4 h which is much shorter than that of conventional sintering. An auxiliary-heating insulation device was designed based on the principle of local caloric compensation to guarantee the intact sintered samples. With the increasing of sintering temperature, more and more microwave energy is absorbed within the entire sample, volumetric densification performs, and phases shift from m-ZrO2 phase to t-ZrO2 phase and cause Al2O3 grain growth.

Keywords:

large size ZTA ceramics, eccentric circle shape, microwave sintering, local caloric compensation
Received: 22 April 2016 Revised: 01 August 2016 Accepted: 08 August 2016 Published: 23 December 2016 Issue date: December 2016
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Publication history

Received: 22 April 2016
Revised: 01 August 2016
Accepted: 08 August 2016
Published: 23 December 2016
Issue date: December 2016

Copyright

© The author(s) 2016

Acknowledgements

This work was sponsored by the National Natural Science Foundation of China (NSFC, No. 51172113).

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