Mullite decomposition kinetics and melt stabilization in the temperature range 1900-2000 degrees C

An investigation of the mullite decomposition mechanism and kinetics in the temperature range 1900-2000 degrees C was conducted. SEM-EDS and XRD analy sis showed that the decomposition of mullite in this temperature range was primarily caused by the presence of carbon from furnace components, A react ion mechanism, in which gas-phase SiO2 reacts with carbon to form SiO and C O, is proposed; both IR analysis and kinetic studies support the proposed m echanism. The decomposition was completely suppressed by the introduction o f a modified crucible assembly and the addition of excess SiO, to the react ion system. A mullite melt of stable composition was thus obtained, setting the groundwork for inviscid melt spinning mullite fiber making process dev elopment.