Thermal Conductivity of β‐Si3N4: II, Effect of Lattice Oxygen

Abstract

Dense β‐Si3N4 with various Y2O3/SiO2 additive ratios were fabricated by hot pressing and subsequent annealing. The thermal conductivity of the sintered bodies increased as the Y2O3/SiO2 ratio increased. The oxygen contents in the β‐Si3N4 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‐Si3N4 that was sintered at various Y2O3/SiO2 additive ratios has been clarified.