Physicochemical Investigation of the Reaction of Components of the Si — Al — O — N — Ti System in the Si3N4 — Al2O3 — AlN — SiO2 — TiN — TiO2 Region. Part 2. Subsystems Si3N4 — AlN, TiN — AlN, Al2O3 — AlN

Abstract

The reaction of components of the Si — Al — O — N — Ti system in its elements Si 3N4 — AlN, TiN — AlN, and Al 2O 3 — AlN was investigated by differential thermal and x-ray diffraction analysis. It was established that upon hot pressing mixtures of Si3N 4 and AlN (up to ∼1950°C) free silicon is formed by the decomposition of Si 3N4, which reacts with oxygen present as an impurity to form SiO. When TiN reacts with AlN a phase with the spinel structure (Al23O 27N 5), which can form only in the presence of excess oxygen, appears in addition to the initial components. Spinel is also produced by the reaction of Al 2O3 with AlN. In this case a eutectic between Al 23O27N5 and Al2O3 is observed.