Process for making a permanent magnet material

Claim 1

A PROCESS OF MAKING A PERMANENT MAGNET MATERIAL, COMPRISING THE STEPS OF FORMING A PARTICULATE MIXTURE INCLUDING A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF THE OXIDES AND OXIDE FURNISHING COMPOUNDS OF FE, A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF THE OXIDES AND OXIDES FURNIDHING COMPOUNDS OF BA, SR AND PB, AND A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF THE OXIDES AND OXIDES FURNISHING COMPOUNDS OF SB, AS AND P;SINTERING SAID MIXTURE IN AIR SO AS TO EFFECT REACTION OF SAID SUBSTANCES AND FORM A FIRST PRODUCT OF THE FORMULA MO. (FE203)6 WHEREIN FET3 IONS IN SAID SB, AS AND P ARE REPLACED BY THE IONS OF AT LEAST ONE OF SAID SB, AS AND P TO SUCH AN EXTENT AS TO CAUSE A LOWERING OF THE TEMPERATURE COEFFICIENT OF THE REVERSIBLE TEMPERATURE CHANGE OF THE MAGNETIC SATURATION MOMENT FROM THAT OF MO.(FE2O3)6 WHEREIN MO REPLACEMENT OF THE FE3 IONS IS EFFECTED, SAID BA, SR AND PB; HEAT AS AND P HAVING A VALENCE IN EXCESS OF T3, AND SAID M OF SAID MO. (FE203)6 BEING AT LEAST ONE OF SAID BA, SR AND PB; HEAT TREATING SAID FIRST PRODUCT WITHIN A TEMPERATURE RANGE OF 1,200* TO 1,350*C SO AS TO CAUSE EVOLUTION OF PART OF THE OXYGEN OF SAID PRODUCT AND SO AS TO CONVERT SAID IONS OF SB, AS AND P TO THEIR TRIVALENT STATE THEREBY FORMING A SECOND PRODUCT; COMMINUTING SAID SECOND PRRODUCT TO SINGLE DOMAIN SIZE; AND TEMPERING THE COMMINUTED SECOND PRODUCT IN A NON-OXIDIZING ATOMPHERE WITHIN A TEMPERATURE RANGE OF 750* TO 1,200*C.