Electrolytic Separation of Al3Ni Fibers from the Eutectic Alloy, Al-Al3Ni

摘要

An electrolytic procedure was developed to remove the trialuminum nickel fibers from the aluminum matrix in the eutectic alloy, Al-Al3Ni. The procedure consists of electrolyzing the aluminum matrix at potentials ranging from -0.8 to +0.5 volt (vs. S.C.E.) in a 1M potassium hydroxide electrolyte. Scanning electron photomicrographs showed that the separated Al3Ni fibers are intact. Anoidic polarization studies with aluminum-nickel alloys illustrated that the presence of nickel protects aluminum from oxidation. Studies with a special fabricated platinum electrode demonstrated that the Al3Ni fibers are not oxidized within the potential range of -0.8 to +0.5 volt (vs S.C.E.) in a 1M potassium hydroxide electrolyte. This decreased rate of oxidation of aluminum in the Al3Ni fibers is correlated with the low rate of diffusion of the aluminum in the Al3Ni orthorhombic crystals. The procedure dose not require the stringent conditions as in other methods of producing Al3Ni fibers from eutectic alloys. The method has the additional advantage of being applicable to a continuous process where the fibers can be removed and the electrolyte replenished. (Author)