In the present study on AlN-based ceramic materials, an attempt was made to show the morphological influence of the precursors on the phase relationships during sintering as well as the microstructural development of the material. An investigation has been done of the phase transformations during pressureless sintering of wear-resistant ceramics based on the AlN-Al2O3-Y2O3 system in the AlN-rich field as well as a study of the effect of different precursors, such as Al2O3, AlCl3 and Al(NO3)3, on the sequence of phase transitions in the low temperature field (800-1400°C). The peculiarities of phase transitions in dynamic and isothermal schedules have also been discussed.