Non-catalytic nucleation coating for undercooled Cu_50 Ni_50 melt

摘要

A ono-catalytic nucleation coating (B-F_3) was prepared by the high temperature curing process of the sol-gel glass film based on the viscous flow mechanism of the coating. X-ray diffraction technology was adopted to study the crystallization behavior of the coating as a function of treating temperature. It was evident that no crystallization phe- nomenon happened on the coating which kept stable after the heat treatment of 60 min at 1773 K. The purified melt of Cu_50Ni_50 was selected to evaluate the effectiveness of undercooling heredity of the coating in the undercooling experi- Ments. The maximum undercooling of the melt solidified in the coated mold could reach 136 K. Based on the solidified microstructural evolution at different undercoolings, a single crystal of the alloy Cu_50Ni_50 was achieved with no aid of the selection process of the crystal in the mold with the B-F_3 coating by means of undercooling technology.