日時 ： ２００９年５月８日（金）※16：30～
場所 ： 愛媛大学総合研究棟Ⅰ 4F 共通会議室（理学部構内）
要 旨
Direct conversion of graphite to diamond under static high-pressure and temperature has recently been investigated in detail (e.g. Irifune et al., 2003) and two different pathways are suggested for the phase transition process on the basis of the microtextural analysis. One is a diffusion process, which involves nucleation and subsequent crystal growth of cubic diamond via diffusion of carbon atoms, and the other is a martensitic process where the transition proceeds by the rearrangement of atoms with maintaining the original structural framework of graphite. These two pathways result in the formation of different types of microtextures; in the former granular texture composed of euhedral crystals with random orientation is formed , whereas in the latter lamella structure made up of layered crystals stacked in the 111 direction. Sumiya and Irifune (2005) reported that such graphite-diamond transition pathways may be controlled by the local stress state of graphite compressed to high pressures. In this study, to experimentally investigate the influence of local stress state in graphite under pressures on the graphite-diamond transition mechanism, a series of laser heated-diamond anvil cell (LHDAC) experiments were conducted and the micro-structure of the recovered products were examined.
問い合わせ先：土屋 卓久 TEL （089）927-8198
E-mail takut@sci.ehime-u.ac.jp
