Yu W.-L.,Metastable Materials Science and Technology |
Zhu X.-F.,Metastable Materials Science and Technology |
Liang B.-Y.,Metastable Materials Science and Technology |
Li Y.,Metastable Materials Science and Technology |
And 3 more authors.
Jingangshi yu Moliao Moju Gongcheng/Diamond and Abrasives Engineering | Year: 2012
The defects in a large diamond crystal synthesized by HPHT temperature gradient method with rapid descent of temperature were studied using white synchrotron radiation topography. Dislocations which originated from the surfaces of the seed and extended along the directions of ± and ± were observed within the crystal grown at the early stage. The crystal was then grown to the[001̄] direction at the middle growing stage and no dislocations were found generated at this stage. A lot of dislocation bundles were generated at the last growth stage of the crystal and each bundle was composed of many straight extended dislocations originated from the same point and extended radially within a sector about 30°. The origins of the dislocation bundles was distributed near the surface of the crystal. Most of the dislocation bundles were generated near the (1̄00) and those near the (100) were in the second place, and still there were some existing near the crystal face (010) and (01̄0). The growth directions of the dislocation bundles was mainly within the range from[1̄00] to[1̄01̄] and near the direction[001̄]. Also, few of the dislocation bundles were found directing to and[01̄0]. The generation of the dislocation bundles was associated with the rapid descent of the temperature in the last growth stage of the diamond crystal. Source