PATENT

3365.  SNOEK, J. L., WENT, J.J., AND HAAYMAN, P. W.  (Hartford National Bank & Trust Co.).  Magnetic Cores.  United States Patent 2,636,860, Apr. 28, 1953. Chem. Abs., vol. 47, 1953, p. 7138.

By mixed-crystal formation of ferrites with positive and negative magnetostriction it is possible to obtain a ferrite with a curie temperature > 50° and ratio of magnetization intensity at saturation to magnetostriction constant >2X10^10.  These materials are suitable for use in magnetic cores for low values of magnetic induction, as in radio, telegraphy, and telephony.  For example, mixtures of MnO₂, ZnO₂, and Fe₂O₃ in molecular ratios of 21-25:25:50-54 are ground for 3 hr. in a ball mill.  From the mixture, with H₂O as plasticization agent, a rod is formed and sintered in pure N₂ for 2 hr. at 1,300°, then cooled in N₂  to room temperature in 0.5 hr.  likewise mixtures of NiO, ZnO and Fe₂O₃ in molecular ratios 12.6-15: 29.4-35: 50-58 were formed into ferrite rods.  Magnetic properties were determined.

SOCIETÀ ANON. CARBURANTI ITALIANI SINTETICI See abs. 2706.