Solidification of superalloy in a SiO2-ZrO2-B2O3 coating mould

The preparation of glass-lined coating mould from gels in the ternary syste m of SiO2-ZrO2-B2O3 has been investigated. The crystallization characteriza tion and high temperature structure stability of this coating mould are dem onstrated. We can find that the crystallization of t-ZrO2 as well as the te tragonal to monoclinic phase transformation are, respectively, retarded and impeded owing to the encasement Of SiO2 matrix. While the inhibitive effec t of B2O3 on crystallization of the SiO2-ZrO2-B2O3 coating mould is explain ed. Finally, DD3 single crystal superalloy melt can realize highly undercoo led rapid solidification by adopting this coating mould, which further evin ces that SiO2-ZrO2-B2O3 coating mould has an ideal nucleation inhibition fo r superalloy. (C) 2001 Elsevier Science B.V. All rights reserved.