Dealloying Behaviours of an Equiatomic TiCu Alloy

Abstract

The crystalline Ti₅₀Cu₅₀ ribbon was prepared by annealing its amorphous counterpart at 773 K, 84 K 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.