The researchers, who are based in the University’s Center for Innovative Sintered Products, say the new process could open the door to injection-moulded niobium parts ranging from rocket nozzles, to wires, to human bone replacements, to orthodontic braces.
Gaurav Aggarwal, doctoral candidate in engineering science and mechanics, presented the team’s work in a paper, Development of Niobium Powder Injection Moulding, at the International Symposium on Tantalum and Niobium in
Aggarwal notes that other researchers have developed techniques for processing niobium via powder metallurgy and some have applied powder injection moulding to niobium-based alloys and superalloys. However, the
The team’s method for calculating the optimal metal powder/binder proportions also can be applied to other materials which, like niobium, have irregularly-shaped particles.
Aggarwal points out that pure niobium products are currently formed from powders and, therefore, there is no powder cost penalty as in ferrous materials, for example. Although it is biocompatible and benign in use, niobium is difficult to control at the high temperatures needed to process it because of its high reactivity.
The resulting part is placed in a solvent that dissolves out the binder and then is heated to drive off the solvent and any remaining binder. The part is then processed in a sintering furnace.
The researchers have validated their approach experimentally. The injection temperature and pressures were determined for optimal filling time based on simulation.