| Reaction Sintering Behaviour of Alumina-Zircon System |
| Lakshman Tiwari, Sanak Mishra*, Devendra Kumar** and R. K. Sinha |
| Abstract |
| 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 graphically, where the ratio
of lp/Ilp (lp is the relative intensity of the strongest peak) fer
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° and 1450°C and is complete within 2-4 h between 1500°
and 1550°C. The isothermal sintering behaviour is studied by
noting the variation of density, linear shrinkage and apparent
porosity. At 1350°C, there is no reaction between alumina and
zircon. At 1450°C the reaction is very slow while at 1550°C it is
complete within 4 h. At 1650°C, complete reaction occurs by the
time the sample is just heated up to the temperature. The effect
of CaO is also investigated. |
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