Mechanical-activation-assisted combustion synthesis of α-SiAlON in air

With the assistance of mechanical activation, yttrium-stabilized α-SiAlON was prepared by combustion synthesis in air, instead of high-pressure N2 atmosphere for the first time. The reaction activity of metallic particles was remarkably enhanced by mechanical activation, which conduced the reduction of grain size, increased the total surface area and formation of fresh surface. The formation of α-SiAlON by combustion synthesis in air was explained by a kinetically induced reaction mechanism, in which both initial formation of α-SiAlON and following avoidance of oxidation were fulfilled by the retardation of O2 infiltration owing to the short reaction period and fast cooling rate.