Microstructure control and its observation of rapid solidification Cu–La alloy for the development of fluoride-ion batteries

We report on the microstructure of Cu-La alloys, which is a candidate material for the electrode of fluoride-ion battery, prepared by the rapid solidification method. The Cu-La alloys near eutectic point (24.5at%La) were quenched at different cooling speed to obtain optimized lamellar microstructure. The cross-section of the Cu-24.5at%La alloy exhibited a lamellar microstructure, in which the Cu-rich and La-rich phases were well proportioned. A hexagonal Cu₅La phase with a space group P6/mmm was confirmed in the Cu-enriched areas, along with tetragonal Cu₄La particles with an I4̅m2 and hexagonal Cu₂La with the P6/mmm. Furthermore, different cooling rate during solidification were applied by changing the wheel rotation speed of the device. The higher the rotation speed, the faster the cooling rate, and the finer the microstructure. The width of each layer in the microstructure was approximately 100 nm.