The influence of in-situ formation of hibonite on the properties of zirconia toughened alumina (ZTA) composites

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• 作者：Zhwan Dilshad Ibrahim Sktani ; Ahmad Zahirani Ahmad Azhar ; Mani Maran Ratnam ; Zainal Arifin Ahmad
• 关键词：ZTA ; Hibonite (CaAl12O19) ; In-situ formation ; Fracture toughness
• 刊名：Ceramics International
• 出版年：May, 2014
• 年：2014
• 卷：40
• 期：4
• 页码：6211-6217
• 全文大小：1579 K

文摘

This paper reports an investigation on the impact of in-situ formation of CaAl₁₂O₁₉ (hibonite) on the microstructure and mechanical properties of zirconia-toughened-alumina (ZTA). Various amounts of CaCO₃ (0-13 wt%) were added to ZTA to form CaAl₁₂O₁₉. Samples were sintered at 800 掳C for 4 h to obtain CaO from decomposition of CaCO₃, and then at 1600 掳C for 4 h to produce elongated CaAl₁₂O₁₉ grains. Analyses of samples were done using XRD and FESEM. The higher the amount of CaCO₃ added, the higher the amounts of CaAl₁₂O₁₉ and pores observed. The toughness value increased with the increase of CaAl₁₂O₁₉ for a critical range, and subsequently decreased; the reverse trend was observed for the hardness and density results. The sample with 0.5 wt% CaCO₃ addition produced the highest toughness (6.3 MPa m^1/2), reasonable hardness (1568.6 HV), density (4.11 g/cm³), and porosity (1.29%) values.