Mass transport of tungsten and molybdenum during production of leucosapphire by horizontal directional crystallization

This paper investigates the mass-transport mechanism of tungsten and molybdenum in the heating unit of an apparatus of the SGVK-Sapphire type, intended for producing leucosapphire by the HDC method. Logarithms of the constants for reactions are presented. However high compared to tungsten oxides, the volatility of molybdenum oxides is determined by the considerable range of mass transport. A possible reason for the co-deposition of amorphous deposit of Mo and Al2O3 surface from dissociation in the system is examined