| 摘要 |
<p>763,809. Magnetic compositions. PHILIPS ELECTRICAL INDUSTRIES, Ltd. Jan. 27, 1955 [Jan. 27, 1954], No. 2494/55. Drawings to Specification. Class 38 (2). A magnetic core is made of a material with a substantially rectangular hysteresis loop and low coercivity and having the formula where x lies in the range 0.1-0.8, y is in the range 0-0.5 and x+y # 0.2, which material is made by heating a mixture of nickel, manganese and iron compounds in an atmosphere containing at least 20 per cent by volume of oxygen at 1400-1475‹ C. Nickel and manganese carbonates and ferric oxide are ground in alcohol preheated in air at 900‹ C., cooled and reground in alcohol, moulded and sintered in air or oxygen at 1450‹ C. Figures to indicate the rectangularity of the hysteresis loops of several substances having different values of x and y are given.</p> |
