This paper deals with the chemical reactions and phase evolution during pressureless sintering of Si3N4 with Mg-exchanged zeolite as sintering additive. The XRD data show that the first MgO-rich liquid forms at as low as 1250 °C, which as a consequence results in a significant reduction of sintering temperature. At 1300 °C the β−Si3N4 phase had disappeared indicating its dissolution into the liquid phase. At 1500 °C the secondary phase had been completely converted into a glassy phase, however, no phase transformation from α−Si3N4 to β−Si3N4 had taken place. Thus the composition of this material consists of α−Si3N4 embedded in magnesium silicon oxynitride glassy phase.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200
