INVESTIGATION INTO CHAIN SELF-IGNITION DURING DICHLOROSILANE OXIDATION BY MEANS OF HIGH-SPEED FRAMING SCHLIEREN PHOTOGRAPHY

Evolution of self-ignition and induced ignition of dichlorosilane-oxyg en mixtures over the pressure range from 4 to 500 Torr at initial temp eratures from 300 to 400 K is studied by means of framing schlieren ph otography. It is shown that self-ignition is of non-thermal nature, an d the reaction begins on the reactor surface with generation of adsorb ed chain carriers which subsequently escape into the volume with a vel ocity of similar to 50 m/s (20%SiH2O2+80%O-2, T=373 K, p(1)=6 Torr). I gnition ends with formation of inhomogeneities - clouds of SiO2 aeroso l - in the volume. SF6 additions to the combustible mixture inhibit se lf-ignition and cause the concentration of SiO2 aerosol to decrease dr amatically SF6 molecules presumably partake in a competing reaction of chain termination involving also charged species.