Preparation of Mullite- and Zircon-Based Ceramics Using Kaolinite and Zirconium Oxide: A Sintering Study
作者:Abla Mecif、Julien Soro、Abdelhamid Harabi、Jean Pierre Bonnet
DOI:10.1111/j.1551-2916.2009.03595.x
日期:2010.2
The interactions between zirconia (ZrO2) powder and three Algerian hydrated kaolinitic clays were studied at high temperatures. The analysis by X‐ray diffraction of the prepared products allowed to follow the different phase developments during heat treatment and to identify the parameters controlling the zirconia conversion into zircon (ZrSiO4). It was found that ZrSiO4 formation, occurring at temperatures above 1150°C, is enhanced by the presence, in the clays, of fusing impurities such as K, Fe, Ca, and Mn, and by a decrease in zirconia particle size. A reactional mechanism, involving zirconia, a flux, and cristobalite is proposed. Moreover, the effect of zirconia additions on sintering was studied. It was also found that the increase in the porosity ratio of the final products for zirconia levels above 20 wt% was governed by a decrease in the flux amount, due to its lower clay content. Finally, it was shown that ceramics obtained by sintering at 1400°C for 2 h of a mixture of 38 wt% of fine zirconia powder and 62 wt% of the more reactive clay were mainly constituted of zircon and mullite.
以下是翻译后的中文内容:
**锆氧化物 (ZrO₂) 粉末与三种阿尔及利亚水合高岭土粘土在高温下的相互作用研究**
本研究在高溫條件下探討了锆氧化物 (ZrO₂) 粉末与三种阿尔及利亚水合高岭土粘土之间的相互作用。通过X射线衍射分析制备的产物,可以跟踪热处理过程中不同相的发展,并识别控制锆氧化物转化为锆(ZrSiO₄)的参数。研究发现,当温度高于1150°C时,ZrSiO₄的形成得到增强,主要原因是在粘土中存在熔融杂质(如K、Fe、Ca和Mn),以及锆氧化物颗粒尺寸的减小。提出了一种涉及锆氧化物、助熔剂和鳞石英的反应机制。此外,还研究了锆氧化物添加对烧结的影响。结果表明,当锆氧化物含量超过20 wt%时,最终产物的孔隙率增加,主要是由于粘土含量降低导致助熔剂减少。最后,研究表明,将由38 wt%细锆氧化物粉末和62 wt%更活性的粘土组成的混合物在1400°C下烧结2小时得到的陶瓷,主要由锆和莫来石组成。