Special Features Of Stabilization Of The Growth Process In Plasma-arc Growth Of Single Crystals Of Refractory Compounds From SHS Products

Problems of the stability of the growth process in growing single crystals of refractory compounds (carbides and bondes of transition metals) by the method of plasma-arc remelting are considered. The main reasons behind the loss of stability of the spatial configuration of the melt (a shift of the anode lock-on of the arc from the center of the molten pool, disturbance of the symmetry of the plasma jet, superheating of the melt) are considered. The effect of cyclic perturbations in the crystallization system that appear upon replenishment on the fluctuation of the energy characteristics of the arc, the temperature of the melt, and the displacements of the crystallization surface is described. It is established that the crystallization rate and the process of coarsening of the crystallites in the formation of a columnar structure in the ingot depend on the frequency of feeding new portions and on their mass.