Edge-defined, film-fed crystal growth
1972; Elsevier BV; Volume: 13-14; Linguagem: Inglês
10.1016/0022-0248(72)90067-x
ISSN1873-5002
AutoresB. Chalmers, H.E. LaBelle, A. I. Mlavsky,
Tópico(s)Solidification and crystal growth phenomena
ResumoCrystal formation from the melt by the edge-defined, film-fed growth process is discussed quantitative in relation to the range of conditions under which continuous growth is possible. It is showin that two distinct modes of growth can occur, in one of which the extraction of latent heat is by radiation into the growing crystal. This is relatively slow process, and because a planar interface is inherently stable in the thermal situation, it can produce crystals of high quality. Also, because of the thermal geometry, there is no upper limit to the cross section that can be grown in this way. The second mode is that in which heat extraction is largely by conduction into and through the liquid film. Crystals can be grown much faster by this process; the interface is inherently unstable, with the result that imperfections arise from cellular or dendritic growth. In the fast mode, the cross section for continuous growth is limited because the position of the interface is stabilized by edge effects, which become inoperative at large cross sections. The quantitative results of these analyses are in close accord with the results of experiments and with observations made in routine production of sapphire crystals.
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