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The origin of synthetic polycrystalline skeletal diamonds
Author(s) -
Substyk M.
Publication year - 1988
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170231205
Subject(s) - graphite , nucleation , materials science , supersaturation , crystallite , crystallization , diamond , crystal growth , synthetic diamond , morphology (biology) , temperature gradient , crystallography , chemical engineering , composite material , metallurgy , thermodynamics , chemistry , geology , paleontology , physics , quantum mechanics , engineering
A reaction vessel for diamond production modified by using a graphite heater around a metal‐graphite sandwich set has changed the physical conditions (especially the thermal conditions) inside the set during the synthesis process. There has been built up a reduced radial temperature gradient, as compared to the gradient in a reaction vessel for repetition work. As an effect of the process polycrystals with very different shapes, morphology, and internal structure have been achieved, and they are named as skeletal polycrystals. Basing on the relation between crystal morphology and its growth conditions, in this paper a suggestion of this polycrystals' growth process is described. It is assumed that the principal driving force of polycrystals' growth process has been the supersaturation of the cobalt solution by graphite. As a result of diamond crystallization, the graphite content decreases and causes the change of growth mechanism from continuous growth through two‐dimensional nucleation to spiral growth. It is well noticed in the skeletal polycrystals' morphology.