The equilibria in the AlN-Al 2 O 3 -Y 2 O 3 system - thermodynamics and neutron diffraction

The importance of aluminum nitride (AlN) stems from its application in microelectronics as a substrate material. Yttria (Y2O3) is the best additive for AlN sintering, and it has been shown that AlN densifies by a liquid-phase mechanism, where the surface oxide, Al2O3, reacts with the oxide additive, Y2O3, to form a Y–Al–O–N liquid that promotes particle rearrangement and densification. Construction of the phase relations in this multicomponent system is becoming essential for further development of AlN. The ternary phase diagram of AlN–Al2O3–Y2O3 was thermodynamically modeled and verified experimentally using in situ high-temperature neutron diffractometry. The ternary phase diagram of AlN–Al2O3–Y2O3 has been constructed for the first time in this work.