new garnet magnetic material

摘要

1310264 Garnets THOMSON-CSF 16 April 1970 [17 April 1969] 18302/70 Heading H1H Ferromagnetic gadolinium - substituted yttrium-iron garnets incorporate tin and calcium oxides within the molecular structure of the compound. In one embodiment, compounds of formula where 0À5#x#0À85 and 0À1#y#0À5 are made by (1) mixing oxides or oxide-yielding compounds of 99À95% purity in proportions defined by Y 3-3x-y Gd 3x Ca y Fe 5-5 # -y Sn y O 12 where 0À02#0À05; (2) crushing the mixture in water in a steel vessel using steel balls for 48 hours, thus eliminating the deficiency 5# of iron; (3) drying and screening; (4) mixing with an organic binder, e.g. PVA; (5) rescreening; (6) pressing the resultant granulate at about 1 ton/cm.SP2/SP; (7) drying and (8) sintering at 1400-1500‹ C. in an oxidizing furnace for at least 2 hours. A variant process embodies the additional steps immediately before mixing with the organic binder, of (1) crushing in water in a steel vessel for 24 hours using steel balls; (2) drying and screening; (3) baking in an oxidizing atmosphere at 1100-1200‹ C. for ¢-2 hours.