Magnetic materials of the high permeability ferrite type

Claim 1

A BODY OF FERROMAGNETIC CERAMIC MATERIAL OF HIGH PERMEABILITY WHICH IS THE REACTION PRODUCT OBTAINED BY HEATING FOR A PERIOD GREATER THAN TWO HOURS AT A SINTERING TEMPERATURE ABOVE 1170*C. IN AN ATMOSPHERIC ESSENTIALLY CONSTITUTED BY AN INERT GAS CONTAINING A SMALL AMOUNT OF OXYGEN, FOLLOWED BY SLOW COOLING IN AN INERT ATMOSPHERE, A MIXTURE OF FERRIC OXIDE, AN OXIDE OF MANGANESE AND ZINC OXIDE THE STARTING MIXTURE OF OXIDES AND THE HEAT TREATMENT YIELDING A FINAL MATERIAL CONTAINING BETWEEN 49.7 AND 50.6 MOL PERCENT OF FERRIC OXIDE, BETWEEN 0.3 AND 7.5 MOL PERCENT OF FERROUS OXIDE, BETWEEN 25 AND 30 MOL PERCENT OF MANGANOUS OXIDE AND THE REMAINDER ZINC OXIDE AND IN WHICH THERE IS ADDED TO THE STARTING MIXTURE OF OXIDES BETWEEN 0.05 AND 1.5%, BY WEIGHT OF THE MIXTURE, OF CARBON.