| 摘要 |
981,942. Magnetic compositions. SIEMENS & HALSKE A.G. July 20, 1962 [July 24, 1961], No. 27964/62. Heading H1H. A process of producing sintered ferrite cores of low operating temperature sensitivity having square hysteresis loops and magnetic switching times of less than 10Ás consisting in magnetically-annealing a sintered ferrite of the kind which shows a constricted hysteresis loop upon cooling after sintering, at a constant temperature of between 10‹ and 100‹ C. below the Curie temperature in a longitudinal magnetic field of an applied strength of at least equal to that required to open the constricted hysteresis loop of the core from linearity and such that with the elapse of time as magnetic-annealing proceeds the the remanence rises towards a maximum, terminating the magnetic-annealing when the remanence is greater than 0.5 of the maximum, and cooling the core. The cores have a composition CO 0 . 02 Mn 0 . 06 Ni 0 . 29 Zn 0 . 43 Fe 2 . 2 O 4 . In performing the annealing cores are threaded on a conductive wire which provides the magnetic field in a muffle furnace. Specification 828,185 is referred to. |
