Reactive synthesis of microporous titanium-aluminide membranes

Titanium-aluminide intermetallic alloys and compounds are traditionally investigated and used as structural materials in high temperature applications. Here we show a novel field where microporous titanium-aluminide membrane with about 20 μm thickness was prepared by a reactive synthesis of a commercial aluminum foil coated with a titanium layer. The porous membrane with the average pore size of about 1.2 μm formed after sintering initially at 550 °C for 4 h and finally at 1300 °C for 30 min, showing a single phase of γ-TiAl. The pore evolution during the synthesis procedure was investigated and analyzed through scanning electron microscopy. The pore formation mechanism is believed to be the Kirkendall effect according to a Ti/Al diffusion couple experiment.