A Study of Synthesis of NiCuZn-Ferrite Sintering in Low Temperature by Metal Nitrates and its Electromagnetic Property

The initial NiCuZn synthetic ferrite were acquired from thermally decomposing the metal nitrates $Fe(NO_3)_39H_2O, Zn(NO_3)_26H_2O, Ni(NO_3)_26H_2O, and Cu(NO_3)_23H_2O$ at $150^circ{C}$ for 24 hours, and then we calcined the synthetic powder at $500^circ{C}$, pulverized each of those for 3, 6, 9, 12, and 15 hours in a steel ball mill, sintered each at $700^circ{C}$ to $1,000^circ{C}$ for 1 hour, and thus studied their microstructures and electromagnetic properties. We could make the initial specimens chemically bonded in liquidity at a low-temperature $150^circ{C}$, by using the low melting points less than $200^circ{C}$ of the metal nitrates instead of the mechanical ball-mill pulverization, then narrow a distance between the particles into a molecular one, and thus lower the reaction point of sintering by at least $200^circ{C}$ to $300^circ{C}$. Their initial permeability was 50 to 400 and their maximum magnetic induction density and coercive force, 2,400 G and 0.3 Oe to 0.5 Oe respectively, which was similar to those of NiZnCu ferrite synthesized in the conventional process. In the graph of initial permeability by frequencies, a $180^circ{C}$ rotation of the magnetic domains which appears in a broad band of micro-wave before and after the resonance frequency, could be perceived.