The reactions were investigated with emphasis on the mass loss during pressureless sintering of Si3N4 ceramics without powder bad. A Si3N4 powder compacts with LiYO2 additive were heat-treated at different temperatures under the pressure of N2 of 0.1 MPa.. The mass loss increased with increasing temperature as well as with increasing additive content. It is expected that the major mass loss should be caused by volatilisation of lithia due to its high vapour pressure. However, the results of the chemical analysis of the samples are in contradiction with this assumption.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200
