| 摘要 |
A novel magnetic ceramic composition and a novel magnetic ceramic used in microwave devices and containing yttrium oxide, iron oxide, tin oxide, aluminium oxide and a calcium source (preferably the carbonate or oxide), are based on formula (I): Y3-xCax/2Snx/2Fe5-yAlyO12, where x = 0.1-1 and y = 0.1-1.5. Also claimed is a process for producing a magnetic ceramic for microwave devices involving: (a) mixing yttrium oxide, iron oxide, tin oxide, aluminium oxide and calcium carbonate or oxide to form a mixture based on the above formula (I); (b) drying and calcining at 1,100-1,200 deg C for 1-3 hrs. to form a calcined powder; (c) adding a binder and then moulding the powder; and (d) sintering at 1,300-1,500 deg C in air.
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