DETERMINATION OF THE FUSION PARAMETERS OF ALUMINUM NITRIDE

Handbook data is used to calculate the temperature and pressure region s for the existence of condensed aluminum nitride in thermodynamic equ ilibrium with the surrounding gas. The first use of the method of melt ing and subsequently cooling a substance is used to obtain polycrystal line aluminum nitride. The brightness melting point of AlN is measured at the wave length 0.633 mum with nitrogen pressures from 10 to 50 MP a. The resulting temperature is 2950 +/- 50 K. The melting point is ob tained by analyzing the heating and cooling curves of ceramic specimen s of aluminum nitride with the use of laser radiation. The occurrence of melting is confirmed by subsequent x-ray analysis of the compositio n and structure of the specimens. Based on literature data on spectral emissivity, the true melting point of aluminum nitride is evaluated a s 3025 +/- 65 K.