Solid-state synthesis of antimicrobial Ti-Nb-Cu/Ni alloys via combined SHS and hydride cycle technologies

In this paper a new method for synthesis of alloys in the Ti-Nb-Cu/Ni system is elaborated, based on Self-propagating High-temperature Synthesis (SHS) and Hydride Cycle (HC) techniques. The essence of this method is the producing the metal hydrides in SHS mode, followed by the formation of alloys in the HC mode. 13 compositions are studied: Ti 0.5 Nb 0.5 , (Ti 0.5 Nb 0.5 )( 1–x) Cu x , (Ti 0.5 Nb 0.5 )( 1–x) Ni x , (Ti 0.5 Nb 0.5 )( 1–x) (Cu 0.5 Ni 0.5 ) x , x = 2.5, 5, 7, 10 (at%). The alloys, containing 66–97.6 wt% of β-phase, are synthesized. The thermograms of HC processes, DTA curves, absence of melting traces on the synthesized alloys indicates a mechanism of solid-phase diffusion reaction of formation of all studied compositions. The antibacterial and antifungal activities of the synthesized alloys are tested by agar diffusion method. The results confirm that the higher the copper content, the higher the antimicrobial activity of the alloy. The synthesis of the antimicrobial alloys in HC from hydrides has significant advantages over the traditional methods: the alloying process is one-stage, waste-free, energy saving, proceeds quickly (1 h instead of dozens of hours) at low temperature (1000°С instead of 1800–2600°C), by solid state mechanism eliminating components melting, etc. Synthesized alloys of refractory metals interact with hydrogen in the SHS mode producing high hydrogen containing, brittle hydrides. Grinding and pressing these hydrides into the mold of an implant, followed by sintering/dehydrogenation at a relatively low temperature (near the decomposition temperature of the hydride) will produce a designed implant. The method makes it possible to use titanium sponge and production waste as raw materials.