Growth of NaBi(WO₄)₂ Dendrite and Mechanism

The solid--liquid interface motion of NaBi(WO₄)₂ (NBWO) melt crystal growth is observed in an in situ system, in which the whole processes of interface transition from flat interface and cellular to dendrite are visualized. The spacing of the dendrite under smaller temperature gradient turns out to be larger than that under larger temperature gradient, which is found to be sensitive to the temperature distribution. The mechanism of dendrite growth of NBWO is studied based on the model of the growth units of anion coordination polyhedra. The 001 face has two apex links, so it shows higher stability and has high growth rate and forms the arm of dendrite, whereas the 010 face has only one apex link, and thus shows relative slower growth rate and firstly forms the branches.