Study of microstructure of chrysotile asbestos by high-resolution electron microscopy

Abstract

Several samples of chrysotile asbestos from different localities, including a synthetic sample, were electron-microscopically observed by the lattice imaging method along two directions parallel and perpendicular to the fibre axis. The results are as follows: (a) The lattice fringes of 4.5 Å corresponding to 020 were often tilted to the edge of the fibrils with an angular distribution ranging up to about 10° with a peak value at a few degrees, depending on the sample. (b) Most of the fibrils examined were hollow cylinders and their circumferential lattice layers form spiral or multi-spiral layers. The perfectly concentric cylindrical layers were also found with a frequency depending on the sample. (c) Unusual growth patterns which cannot be explained by Jagodzinski and Kunze's model were observed. (d) The lattice images of the cortical fibrils (cone-in-cone shape) were observed in the synthetic sample. (e) Most fibrils greater than about 350 Å in diameter showed traces of discontinuous growth in two or three steps, depending on the growth conditions, and this gave rise to various distributions of the fibril diameters.