Cobalt Oxalate Formation on Thin-Film Magnetic Recording Media

Needle-like crystalline nanostructures were formed on the surface of a lubricated experimental thin-film media during exposure to elevated temperature and humidity. Clusters of nodules were formed on unlubricated media during the same exposure. Both the needles and nodules were identified as cobalt oxalate by Micro-Raman spectroscopy. A chemical mechanism is proposed to explain how cobalt hydroxide corrosion product and atmospheric oxalic acid combine to form cobalt oxalate in the presence of moisture