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.