Deposition of Al65Cu23Fe12 and Composite Quasicrystalline Pvd Thin Film Coatings

Abstract

AbstractThin film coatings of Al-based quasicrystals were deposited by magnetron sputtering. Sputtering targets of Al65Cu23Fe12 and Al65Cu23Fe12+5v/o Fe-Al were prepared with plasma arc spraying by forming thick (∼5mm) coatings onto Cu substrates. By incorporating a controlled fraction of porosity and micro-cracks within the plasma sprayed target, cracking or delamination of the target during magnetron sputtering could be avoided. Compositions of the as-deposited PVD films were close to the sputtering target composition when the bias voltage was kept around –40V; higher bias voltages (e.g., -100 to -200V) lead to coatings that were deficient in Al. As-deposited coatings prepared with the lower bias voltage could be subsequently annealed at 700°C for two hours to yield a nearly single-phase icosahedral structure. After annealing, composite coatings indicate the presence of an Fe-Al phase along with the icosahedral phase.