dioxane and placed in a shaker for two hours than 45 g of polyester urethane sold commercially as estane 5703 in the form of a 10 solution dissolved in para dioxane was added to the mixture shaking of the chromium dioxide polymer and solvent was then carried out for one hour then 0 4 g of mondur mrs polymethylene polyphenyl isocyanate supplied by mobay company was added to the mixture as a cross linker the resulting ink was then knife coated on a 1 5 mil thick polyester substrate dried calendered and then cured for 48 hours at 60 u00b0 c the resulting tape was found to serve as an excellent magnetic recording media excellent recording media was also prepared from chromium dioxide prepared in accordance with the process set forth in example i uses for the materials produced in the foregoing examples are well known as detailed in example vii above the cr vi free ferromagnetic cro 2 compositions produced by the examples may be mixed with non magnetic organic film forming binders and utilized to prepare magnetic recording media the resulting media is free of cr vi contamination from the chromium dioxide and thus avoids this source of magnetic and physical deterioration typical but not limiting binders for use singularly or in.