화학공학소재연구정보센터
Journal of Crystal Growth, Vol.310, No.7-9, 2141-2147, 2008
Advanced technologies of shaped sapphire fabrication
The properties of sapphire make it an ideal material for high-tech applications. Industry needs a broad range of forms and sizes of sapphire crystals as well as their appropriate quality. The Stepanov (EFG) technique and its variations allow producing directly from the melt sapphire crystals in the form close to the final shape of an article and also presents itself as the best choice to grow the largest area sapphire windows. From the point of view of equipment complexity, crystallization unit design and automated process control sub-methods of EFG can be divided into three categories: the conventional EFG for pulling of ribbons, rods and tubes; modified EFG (local dynamic shaping (LDS) technique) for producing sapphire crystals in the form of complex hollow bodies with a revolution axis; and growth of an extra-large sapphire window. All mentioned types of crystals have been fabricated in the Crystal Growth Laboratory of EZAN RAS. In this paper we would like to represent basic aspects of crystallization, process-automated control and quality data for each type of shaped sapphire crystals. The following technologies are considered: growth of sapphire ribbons rods and tubes; large-scale sapphire domes and cones growth from the melt by the LDS technique (the dome base diameter is 115mm); and growth of 300-mm-wide sapphire window. (C) 2007 Elsevier B.V. All rights reserved.