Combustion synthesis of Si₂N₂O powder for photovoltaic silicon casting application

Single-phase silicon oxynitride (Si₂N₂O) was prepared in a N₂ atmosphere by combustion synthesis with Si and SiO₂ as the reactants. The effects of process parameters, including N₂ pressure, Si₂N₂O diluent and NH₄Cl content, on the combustion temperature, as well as phase composition and microstructure of products were investigated. The high-temperature wetting behavior of Si melt on the as-prepared Si₂N₂O coating was then tested by the sessile drop method. It was found that Si melt shows poor wettability to Si₂N₂O coating at 1500 °C with the steady contact angle of 120°, indicating that the combustion-synthesized Si₂N₂O powders could be used as a potential novel releasing agent material for photovoltaic silicon casting application.