초크랄스키법을 이용한 Terfenol-D 성장시 희토류 원소의 손실과 거시편석 거동

Giant magnetostrictive material Terfenol-D was grown by Czochralski method in various melt temperature under purified argon at 1.2 atm and the macrosegregation of RE along growth direction was investigated. It can be expected that concentration of RE elements follow the Burton-Prim-Slicter relation in Czochralaki system. However, the aspects of macrosegregation were changed with melt temperature: At lower melting temperature, RE elements concentration increased slong growth direction, while at higher, it decreased. This was due to the change of melt composition during growth caused by loss of RE. Therefore, we discussed the reaction of RE with crucible and evaporation through free surface, which are the main reasons of RE loss. In addition, the macrosegregation was discussed considering the loss of RE with melt temperature.