Reaction Sintering Behaviour of Alumina-Zircon System

• Published in: Transactions of the Indian Ceramic Society 2001, Vol.60 (3), p.130-136
• Main Authors: Tiwari, Lakshman, Mishra, Sanak, Kumar, Devendra, Sinha, R. K.
• Format: Article
• Language: English
• ISSN: 0371-750X; 2165-5456
• DOI: 10.1080/0371750X.2001.10799986

Alumina and zircon are mixed in a proportion which gives mullite and zirconia phases after sintering. The formation of mullite and zirconia by reaction sintering is monitored by X-ray diffraction. The phases are identified from the X-ray diffraction patterns and the reaction behaviour is represented graphicalty, where the ratio of I p /ΣI p (I p is the relative intensity of the strongest peak) for each phase is plotted as a function of temperature. As the reaction proceeds, the amounts of alumina and zircon decrease, whereas the amounts of mullite and zirconia increase. It is observed that the reaction starts at some temperature between 1400 o and 1450 o C and is complete within 2-4 h between 1500 o and 1550 o C. The Isothermal sintering behaviour is studied by noting the variation of density, linear shrinkage and apparent porosity. At 1350 o C, there is no reaction between alumina and zircon. At 1450 o C the reaction is very slow while at 1550 o C it is complete within 4 h. At 1650 o C, complete reaction occurs by the time the sample is just heated up to the temperature. The effect of CaO is also investigated.