LOW-ENERGY LASER IGNITION OF MAGNESIUM TEFLON-VITON COMPOSITIONS

Ignition of unconfined pellets of magnesium-Teflon-Viton compositions by unfocused low-energy non-Q-switched Nd/glass laser pulses of wavele ngth 1060 nm has been investigated using high-speed framing photograph y. Ignition has been found to initiate at localized sites which are pr obably centred on the magnesium particles in the compositions. Ignitio n was obtained for an estimated absorbed energy of 9.1 +/- 0.7 mJ when a 3 mm diameter area of the test sample was irradiated with the laser beam and the time delay between the start of the laser pulse and init iation of ignition was 20 mus. By comparing the delay time to ignition with the time measurements at relatively low temperatures, it is conc luded that the mechanism of ignition by laser irradiation is thermal i n origin.