ANTICORROSIVE TREATMENT OF MAGNETIC METAL POWDER FOR MAGNETIC RECORDING

摘要

PURPOSE:To contrive preventing the reduction of saturated magnetization by preventing the forming of an oxide film on the surface of metal powder by dipping the magnetic metal powder in an organic solvent which contains gallic acid ester. CONSTITUTION:If magnetic metal powder is dipped in an organic solvent which contains gallic acid ester, the gallic acid ester adheres to the surface of the magnetic metal powder, remains after the solvent is evaporated and covers the surface of the magnetic metal powder. This prevents the contact of the surface of the magnetic metal powder with oxygen and the oxidation of the magnetic metal powder is prevented by the earlier reaction with the oxygen of the gallic acid ester which is more active with the oxygen than the reaction of the magnetic metal powder. The quantity of the gallic acid ester is desirable to be 0.5-8wt% ratio of the magnetic metal powder.