Alloy powders for magnetic recording tape

A new process for making acicular Fe-Co alloy particles for high density recording tapes and for master tapes of magnetic contact printing is presented. The method consists of adsorption of Co(OH)2colloid on the surface of fine goethite particles, heat treatment at 700°C in air to diffuse Co++ into the particles, followed by reduction to the metallic alloy state. The alloy powders with 10 to 50 atm % of Co showed coercive force higher than 1000 Oe and saturation magnetization greater than 160 emu/g. The characteristics of new alloy powder tapes prepared by the adsorption method are measured and comparison with those of CrO2and γ-Fe2O3tapes are given.