| 摘要 |
<p>1511379 Producing ferromagnetic powder FUJI PHOTO FILM CO Ltd 22 July 1975 30697/75 Heading C7D A ferromagnetic material is produced by mixing an aqueous solution of at least one salt of a ferromagnetic metal and whose pH has been adjusted to #3 with a solution of a reducing agent, at p#8, containing at least one boron hydride compound or a derivative thereof. The salt preferably contains one of Fe, Co, FeCo, FeNi, and FeNiCo, with, if desired salts of rare earth metals e.g. La, Ce, Nd, Sm, or Ti, Zr, Cr, Mn, W, Mo, Re, Pt group, Cu, Ag, Zn, Al, Sn, Pb, Sb, As or P. Suitable salts are the sulphates, sulphides, chlorides, nitrates, formates, acetates, and formamates. The reducing agent may be borazane, borane, borohydride. NaBH4, KBH4, dimethylaminoborane or diethylaminoborane and may be dissolved in water or methanol. The aqueous solution may contain pH adjusting agents and polar organic solvents, examples of which are given. A magnetic field may be applied during the reaction, e.g. 500-3000 Oe, and ultrasonic vibration may be used the reaction taking place at or below 65‹C at 0À5-5À0 atmospheres. The ferromagnetic powder is collected and prepared for use in the manufacture of tapes. Preferred alloys are Fe-Co with Ti, Cr, Mn, Ni, Cu, Zn, Al, Pb or P, and Fe-Co-Ni with one of these elements.</p> |
