Dealloying Behaviours of an Equiatomic TiCu Alloy

The crystalline Ti50Cu50 ribbon was prepared by annealing its amorphous counterpart at 773K, 84K higher than its crystallization temperature. An equiatomic TiCu intermetallic phase dominated in the matrix coexisting with trace Ti2Cu phase segregated on the grain boundary. A bi-continuous nanoporous copper from tenths of nanometers to hundredths of nanometers was obtained after dealloying the crystalline Ti50Cu50 ribbons in 0.03 and 0.13 kmol/m3 HF solutions. The TiCu phase stayed inert at the initial immersion and the Ti2Cu zone preferentially dissolved to form trenches. After a prolonged immersion in HF solutions, both TiCu and Ti2Cu phases were fully dealloyed. Final nanoporous Cu had a multiple-channel characteristic in different regions where various intermetallic phases distributed. Finer nanoporous Cu formed in the regions where the TiCu phase with a higher electrochemical stability dominated. [doi:10.2320/matertrans.M2013033]