STUDY OF ALUMINA CRYSTAL STRUCTURES (AUTOMATION OF THE VERNEUIL PROCESS).
Final rept., 1 May 62-31 Oct 65,
MICHIGAN UNIV ANN ARBOR INST OF SCIENCE AND TECHNOLOGY
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A careful analysis of the basic mechanisms of the Verneuil process led to a methodical study of the many parameters associated with it. Among these, the powder feed rate, boule retraction rate, and flame characteristics were found to be most important. A photoelectric cell was used to sense the plane of crystallization and control its position by means of a servosystem with two outputs, one controlling the retraction rate and the other the powder feed rate. A completely automated Verneuil apparatus, incorporating this and other control systems, was designed and constructed to study crystal growth under well defined, rigidly controlled and dependably reproducible conditions. Author