EXPERIMENTAL IGNITION TIME DETERMINATION FOR A PARTICLE FORMED DURING METAL DISINTEGRATION IN OXYGEN

In order to estimate the order of magnitude of the ignition time for metallic particles with a clean (not covered with an oxide film) surf ace, and which are produced when a metal is disintegrated in a gaseous oxygen atmosphere, for a particular case measurements were taken of the time interval from the particle formation instant to the appearance of noticeable radiation in the visible spectrum. In the present work this time interval is considered to be the characteristic particle ignition time. The investigated particles were formed by the perforation of a stainless steel (12Kh18N9T) foil target by a cylindrical pellet made from the same material. The pellet impacting velocity was about 640 m/sec. The experiments were performed in oxygen at room temperature and at atmospheric pressure. This was the minimum pressure, at which an ignition of the investigated particles could be observed. The measurements showed that under the conditions, at which the experiments were carried out, the ignition time of stainless steel particles with a clean surface was less than about 1-mu-sec.