Document wqMMGpw4zmx14YdJvdjvkeReQ

* with * `s (A27) JIRO KAK1NOKI AND TERUAK1 MINAGAWA 659 Since the structure is the complex APD structure of the t>[< GAfJ | (A?)), we should have war"w!i! (A33) 'hi', meaning that the following relation holds in general: {0,}-2{0;). (A36) As a result, we have &><j> * w<V, + - utir, j and hence I *w>+w,T>-+ tuj-JI) , (A.34) (A35) Refcreacts FuJtWAXA, K. (1957). J. Phys. Soe. Japan, 12, 7. Kakinoki, J. (1962). J. Phys. Soe. Japan, 17, Supplement B-ll, 267. Kakikioki. J.. Kodeaa, E. & Aikaso, T. (1969). Acta Crysi. A 25, 3B5. lion A28) and A29) V30) freh ) 20. ie in . we s31) by,: ncy. the the'. 32) ( Ada Cryst. (1971). A27,659 Study of Microstructure of Chrysotile Asbestos by High Resolution Electron Microscopy j ' Bv Kf.iii Yada I Research Institute for Scientific Measurements, Tohoku University, Sendai, Japan 1 i {Received 3 February 1971 and tn revised form 20 July 1971) '. (Dedicated to Professor Tadatosl Hibi in honour o, his 61 si birthday) 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 A 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. (6) 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 wers observed. (J) The lattice images of the conical Abrils (cone-in-cone shape) were observed in the synthetic sample, (e) Most fibrils greater than about 350 A 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. Introduction one source (Quebec, Canada,) and, moreover, the ob servation of the detailed structure at the inter- and From studies using the methods of X-ray diffraction, intra-fibril sites was hindered by the damage due to electron microscopy and electron diffraction, it has irradiation by the electron beam required for high been pointed out that there are morphological and magnification electron microscopy. Therefore, in order structural variations in chrysotile asbestos (Whittaker, to obtain a comprehensive understanding of the micro- 1951; Jagodzinski & Kunze, 1954; Whittaker, 1955, structures and growth mechanism of chrysotile, it 1956d,b,c, 1957; Whittaker & Zussman; 1956). In seemed desirable to study samples from different loca earlier X-ray studies, however, tingle crystals were not lities by the use of a improved technique by which the available, while in subsequent studies made on single radiation damage was minimized. crystals (individual fibrils), by means of electron mi- croscopy combined with selected area electron diffrac:7. tion, the instrumental resolution was not high enough The specimens and experimental technique to resolve the fine structures (Hoiijo Sc Mihama, 1954; Table 1 shows a list of the samples examined. Most of ; Zussman, Brindley & Comer, 1957; Bates & Comer,' these samples are chrysotile ores, except the last one : 1?57). which is powder Mg-chrysotile synthesized under con Recently, it has become possible to observe lattice trolled conditions (Noli, Kircher & Sybertz, 1958, .. planes in the individual fibrils of chrysotile (Fernandcz- 1960), . .yMorin, 1966; Yada, 1967), and it'has been found, for A small-quantity ..of chrysolite,was torn off with ,.v ['.^example,rthat the circumferentially^ ob-'>'$.tweezers, and as-in-tfc;lpii^/pi. work (Yada, 1967) ' ! '^'served in the cross-section oT a: fibril Show a spiral of `'observations were madeTrom^wo directions, parallel ' multi-spiral structure. The previous work by the pres and perpendicular to the fibre axis, employing the sec ent author, however, was done for a sample from only tioning technique by ultramicrotomy as well as the , '."X n --rtr - - SCF-FA-6510 5000 0569 -------------- t&l 9!-f# PRODUCED BY FORD