Low temperature sintering of iron deficient Z type hexagonal ferrites

Low temperature sintering of iron deficient hexagonal Co2Z type ferrites is attempted to prepare a chip inductor for ultra high frequency uses. It should be attained below the melting point of silver (960 °C) used as the electrode material of the chip inductor. The best result is obtained for the sample with the composition 2.15Co0.6Cu0.4O·3Ba0.79Sr0.16Bi0.05O·9.725Fe2O3 sintered at 925 °C containing 0.5 wt.% of lithium bismuth oxide as a sintering additive. Its density and permeability reaches 5.0 g/cm3 and 7, respectively. As a result, the impedance of the chip inductor also reaches 390 ohm at 2 GHz using this material.