Physical vapor deposition route for production of Al–Cu–Fe–Cr and Al–Cu–Fe quasicrystalline and approximant coatings

A novel route for production of Al–Cu–Fe–Cr and Al–Cu–Fe quasicrystalline and approximant coatings by physical vapor deposition (PVD) methods is described. Powdered elemental stoichiometric mixtures were formed and vacuum pressed at 400 °C in a graphite die to produce ≈50% dense sputtering targets. X-ray diffraction analysis performed on the expended targets revealed elemental Al and Cu phases with significant quantities of intermetallic θ (Al2Cu) and/or λ (Al13Fe4) phases also present. These targets were used to sputter thick (10 μm) precursor coatings onto alumina substrates. Predominantly O1 approximant decagonal approximant coatings were produced by sputtering from the Al–Cu–Fe–Cr target and subsequent annealing in vacuum in flowing argon at 500 °C for 4 h. Icosohedral and rhombohedral approximant phases are produced by sputtering from the Al–Cu–Fe target and annealing in argon at 850 or 450 °C, respectively.