| 摘要 |
759,248. Magnetic compositions. PHILIPS ELECTRICAL INDUSTRIES, Ltd. Dec. 22, 1954 [Dec. 22, 1953], No. 37111/54. Drawings to Specification. Class 38 (2). A magnetic core is made of a material with a substantially rectangular hysteresis and low value of coercivity, and having the formula Cu x Mn (1-x+y) Fe 2 O 4' where x lies in the range 0.05 and 0.02 and y < 0.7, which material is made by heating a mixture of copper, manganese and iron compounds in air or an atmosphere containing more oxygen than is found in air at 1350-1400‹ C. Manganese carbonate and copper and ferric oxides are ground in alcohol, preheated at 900‹ C., cooled and reground in alcohol, moulded and sintered at 1350‹ C. in oxygen. Figures are given to indicate the rectangularity of the hysteresis loops of several substances having different values of x and y. |
