Physicochemical and structural investigations of Si3N4 and AlN powder mixture product using plasma treatment

The paper presents research results of the β-SiAlON production from aluminum, silicon and urea nitrides using high-enthalpy thermal plasma flow. Physicochemical properties of β-SiAlON are studied by using the X-ray phase analysis, scanning electron microscopy, and differential  thermal  analysis.  It  is  shown  that  at  the  spicified  plasma  jet  parameters, a thermochemical reaction occurs with the formation of β-Si5AlON7. Three zones of the structure formation caused by the temperature gradient in the bulk material as a result of the plasma exposure, are identified and studied. The first zone is directly irradiated by the plasma. The second is the transition zone, which locates between the first and third zones. The third is the thermal heating zone provided by the heat transfer from the irradiated zone.