The aim of this paper is to study the reaction between TiNi alloy and a new kind of Boron nitride based shell mold used for investment casting titanium alloys

and the formation mechanisms of the reaction layer between Ti-Ni alloy and BN based shell mold is also discussed. The results show that the reaction is slight and the thickness of the reacting layer is only about several micrometers. The new kind of Boron nitride base shell mold will substitute for the traditional investment mould of the casting titanium alloys such as Y2O3 or ZrO2 based shell mold at a lower casting temperature.