Thermal Conductivity of β‐Si ₃ N ₄ : II, Effect of Lattice Oxygen

Abstract

Dense β‐Si 3 N 4 with various Y 2 O 3 /SiO 2 additive ratios were fabricated by hot pressing and subsequent annealing. The thermal conductivity of the sintered bodies increased as the Y 2 O 3 /SiO 2 ratio increased. The oxygen contents in the β‐Si 3 N 4 crystal lattice of these samples were determined using hot‐gas extraction and electron spin resonance techniques. A good correlation between the lattice oxygen content and the thermal resistivity was observed. The relationship between the microstructure, grain‐boundary phase, lattice oxygen content, and thermal conductivity of β‐Si 3 N 4 that was sintered at various Y 2 O 3 /SiO 2 additive ratios has been clarified.