The effect of aluminum additive on structure evolution of silicon oxycarbide derived from polysiloxane

Abstract

Silicon oxycarbide (SiOC) and aluminum-containing silicon oxycarbide (SiAlOC) glasses were obtained through pyrolysis in argon atmosphere at 1000 °C of a polymethyl(phenyl)siloxane resin and aluminum tri-sec-butoxide-derived siloxane networks. These glasses were further annealed at 1200, 1300, and 1400 °C in vacuum atmosphere to investigate their high-temperature behavior. The two types of glasses were characterized by X-ray diffraction, 29SiMASNMR, 27AlMASNMR, and chemical element analysis. The aluminum incorporated into structure plays a major role on the thermal stability of SiOC by hindering carbothermal reductions. It can be found that introducing aluminum into structure should be an effective way to enhance the thermal stability of SiOC glasses.