Pulsed laser heating of soot: morphological changes

Pulsed laser heating of carbon soot is used here to achieve heating in exce ss of 10(11) K s(-1), cooling rates on the order of 10(9) s(-1) and total i ntegrated times at elevated temperature of ca 1 milliseconds. To resolve de tailed morphological changes induced in the soot by pulsed high intensity l aser light, high resolution transmission electron microscopy and selected a rea electron diffraction are used to examine the laser-heated soot. Partial graphitization, formation of hollow particles and the average number of gr aphitic planes formed within soot primary particles upon high intensity pul sed laser heating are explained via a thermal annealing mechanism. This mec hanism is discussed in the context of the initial physical structure of the soot. (C) 1999 Elsevier Science Ltd. All rights reserved.