method for the manufacture of a ferrits, particularly suitable for impulsrelaiskerne

摘要

1,074,178. Magnetic compositions. TELEFONAKTIEBOLAGET L. M. ERICSSON. Nov. 29, 1965 [Dec. 16, 1964], No. 50658/65. Heading H1H. A sintered ferrite having high reesistivity coercivity and remanence has the formula 1+x where 0À01 # x # 0À04 and y # - and up to 10 50 atomic per cent of the Zn may be replaced by Cd and up to 5 atomic per cent of the Fe may be replaced by Mn. While being held at the sintering temperature the temperature of the material is raised rapidly by 100‹ C. and immediately reduced to its former value. The constituents may be pre-sintered at 1000‹ C., cooled and ground to 1Á, mixed with polyvinyl alcohol in water and Zn stearate, moulded; sintered at 1100-1300‹ C. in air Œ O 2 , and cooled in two stages, e.g. to 750-1050‹ C. and held there for 12-18 hours, then cooled rapidly. The ferrite is used for pulse relay cores.