Ceramics-Silikáty 62, (1) 1 - 7 (2018) |
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EFFECTS OF NANO-ZrO₂ ADDITIVE ON THE PHASE TRANSFORMATION AND DENSIFICATION OF ZrO₂-MgAl₂O₄ CERAMICS PREPARED BY SINGLE-STAGE SRS PROCESS
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Zhang Yaran 1, Ma Beiyue 1, Su Chang 1, Yu Jingkun 1, Li Guangqiang 2, Zhu Qiang 3
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1 School of Metallurgy, Northeastern University, Shenyang 110819, PR China
2 The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, PR China
3 Electron Microscope Unit, Mark Wainwright Analytical Centre, The University of New South Wales, Sydney, NSW 2032, Australia
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Keywords: MgAl₂O₄, Nano-ZrO₂, Reaction sintering, Phase transformation, Densification
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A series of ZrO₂-MgAl₂O₄ ceramics with additions of 0, 2.5wt%, 5.0wt% and 7.5wt% nano-ZrO₂ were successfully fabricated at 1580 °C for 4 h from powders of commercial Al₂O₃ and calcined MgO by single-stage solid state reaction sintering (SRS) method. Effects of nano-ZrO₂ additive on the phase compositions, microstructures and bulk density of the ceramics were investigated. Nano-ZrO₂ additive was found to remarkably promote the sintering densification and improve the microstructure of the ceramics. Uniform, dense and fine microstructures are obtained, and the mean grain size of MgAl₂O₄ particles is about 2 μm. The as-prepared ceramics mainly consist of MgAl₂O₄ and c-ZrO₂ (cubic-Ca0.15Zr0.85O1.85), due to the reaction between Al₂O₃ and MgO as well as the nano-ZrO₂ additive and CaO stabilizer. The formation process of the ceramics mainly includes the synthesis of MgAl₂O₄ and the conversion process of m-ZrO₂ to c-ZrO₂ under the stabilizing action of CaO. |
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doi: 10.13168/cs.2017.0038
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