Optimization of the FFC Cambridge process for NiTi production

The FFC Cambridge process is ideal for NiTi production, as it avoids the Ni segregation associated with pyrometallurgical routes to manufacture NiTi, and is able to produce a homogenous low-oxygen product. The process involves the direct electrodeoxidation of NiTiO3 (first stable oxide to form upon mixing and sintering of NiO and TiO2) to NiTi in a molten CaCl2 salt bath. This work builds on previous literature that has elucidated the reduction pathway by investigating the effect of reduction temperature and current collector material on the microstructure of the final reduction product. It was found that the use of a Ni current collector caused Ni-enrichment at the surface of the product, stabilizing the high temperature B2 cubic form to room temperature. Ni-rich phases Ni4Ti3 and Ni3Ti were observed after 24h reductions. The former is favoured at higher reduction temperatures, and the latter at lower temperatures. Mechanisms for formation are proposed.