Oxygen content of α-silicon nitride powder depending on the synthesis method

Abstract

Wet classification was carried out on α-silicon nitride powders prepared by different methods, and the amount of dissolved oxygen and surface oxygen was measured using carrier gas hot extraction method. As a result, the amount of surface oxygen varied systematically depending on the class. The thickness of the oxide layer estimated from the amount of surface oxygen was 0.2–0.5 nm, which was the same as the values reported by X-ray photoelectron spectroscopy and Auger electron spectroscopy. On the other hand, the amount of dissolved oxygen was almost constant regardless of the specific surface area. The powder prepared by direct nitridation method showed a lower amount of dissolved oxygen than the powders prepared by combustion synthesis method.