Evaluation of Anisotropy and Preferred Orientation of Carbon and Graphite Materials Yoshihiro Hishiyama Fig.1 Diffraction condition in Fourier space.

Evaluation of Anisotropy and Preferred Orientation of Carbon and Graphite Materials Yoshihiro Hishiyama Fig.1 Diffraction condition in Fourier space. Corresponding Author, E-mail: yhishiya@eng.musashi-tech.ac.jp Musashi Institute of Technology: 1-28-1 Tamazutsumi, Setagaya-ku, Tokyo 158-8557, Japan

Fig.2 Distributions of the reciprocal lattice points on the 002 sphere with the radius 2:0d., in the Fourier space, (a) pressed sample, (b) extruded sample. The z axis is that of symmetry, the axis of pressing for (a) and that of extrusion for (b). Fig.4 Ideal orientation functions, for (a) pressed sample and (b) extruded sample. Fig.3 Specimens for measurements of orientation function by X-ray diffraction technique, for (a) pressed sample and (b) extruded sample. Three types in axial orientation are also shown in (c).

Fig. 5 Example of sample holder. Fig. 6 (a) Scheme of orientation function measurement. (b) Scheme of 002 diffraction intensity measurement with offset angle a for determination of orientation function. Sample reference plane is the plane includes the sample rotation axis and perpen dicular to the axis of pressing. The lattice planes parallel to the reference plane diffract incident X-rays. When the - sample rotates by angle ƒæ, the reference plane also rotates angle by ƒæ and the counter rotates by angle 2ƒÆ. ƒ corresponds to the angle for orientation function I(ƒÆ).

Fig. 7 Geometry for orientation function measurement in Fourier space. (a) An X-ray beam incidents parallel to the sample surface, i.e. parallel to the 002 planes of the crystallites. (b) With sample rotation, the reciprocal lattice rotates and the reciprocal vector G002 intersects the Ewald sphere when the diffraction condition is satisfied and the diffracted beam with k' are radiated. (c) For the sample with planer orientation, G002 distributes on the 002 sphere. With fixing the position of the counter and rotating the sample, the 002 sphere rotates and the counter records the distribution of G002 on the 002 sphere as the intensity of the diffracted beam.

Fig. 8 Orientation functions for high temperature-treated samples of pyrolytic graphites.

Fig. 10 Peak intensity recordings of 002 diffraction plotted as a function of sample rotation angle for the HOGF and boron-doped HOGF samples3). Fig. 9 X-ray diffraction patterns for HOGF and Boron-doped HOGFs measured in reflection and transmission modes*, (a) HOGF, (b) Boron-doped HOGF with 0.4 at. % boron and (c) Boron-doped HOGF with 2.2 at. % boron. *; Y. Hishiyama, unpublished data. Fig. 11 004 diffraction patterns for HOGF and boron-doped HOGF's3).

Fig. 12 Sample mount for pencil lead as a sample A. Fig. 13 002 diffraction patterns as functions of sample rotation angles for pencil leads. (A) for lead with 0.2mm dia., and (B) for that with 0.3mm dia.2). Fig. 14 Normalized orientation functions measured for pencil lead samples, (a) for that with 0.2mm dia., and (b) for that with 0.3mm dia.2).

Fig. A1 Definition of solid angle. Fig. A2 Surface element ds on a sphere of radius r. 2) Y. Hishiyama, H. Tomita, Y. Sasaki and M. Nakamura, TANSO 1994 [No.164] 222-229 [in Japanese]. 3) Y. Hishiyama, H. Irumano, Y. Kaburagi and Y. Soneda, Phys. Rev. 64 (2001) 245406. 5) Y. Hishiyama, M. Nakamura, Y. Nagata and M. Inagaki, Carbon 32 (1994) 645-650. 6) Y. Kaburagi, A. Yoshida and Y. Hishiyama, J. Mater. Res. 11 (1996) 769-778. 7) Y. Kaburagi, A. Yoshida, H. Kitahata and Y. Hishiyama, TANSO 1996 [No.171] 24-29 [in Japanese].