Production of free standing Cu–Al intermetallics by cathodic arc plasma treatment

In this study a new approach, based on modification of surfaces by energetic ion bombardment produced through cathodic arc plasma was utilized for the production of bulk Cu–Al compounds. Alloying was done in a cyclic manner by depositing aluminum under low bias voltages, and then by enhancing diffusion/mixing by applying a high bias voltage (bombarding). During the bombarding step, substrate temperatures in a range of 750–800 °C can be achieved depending on the duration in a time scale of seconds where copper foils with 25 μm thickness were used as substrates. For homogenization of the as-processed samples, a vacuum annealing heat treatment was applied at 700 °C for 24 h. Single phase α1-Cu solid solution, and γ1-Al4Cu9, δ-Al2Cu3, and ζ2-Al3Cu4 intermetallics were successfully produced. Structural and surface/cross sectional investigations of the samples were conducted with XRD, SEM and EDS measurements. The micro-hardness of the phases, was also determined.