Mgtio <sub> 3 </ Sub> / Nizncu Ferrite Composite Materials, Low-temperature Sintering Research And Applications

The materials of EMI filter, LTCC process and filter structure were studied systemically to meet the demands of R&D program of Shenzhen ZhenHuaFu electronic ferrite & ceramic company. And a filter model of EMI low pass filter with cutoff frequency at 50MHz was set up.First of all, NiZnCu/MgTiO3 composite was developed with chemical reactions. The composite keeps its components'crystals. Both permeability and relative permittivity are between the two components'. Different oxide with low melting point such as Bi2O3,V2O5,B2O3 and CuO were added for the purpose of reducing sintering temperature. Sintering temperature is lower to 920℃by adding 3wt% Bi2O3. The permeability and relative permittivity of composite meet the requirements of EMI filter under the mass rate 6:4 of NiZnCu and MgTiO3. And composite is more active, the ceramic is more compact when pre-sintered at 850℃.Second, on the process platform of Shenzhen ZhenHuaFu electronic ferrite & ceramic company, wet tape-cast experiment was done. According to the special elements of the composite and the solvent system of ferrite and ceramic, the solvent system of the composite was explored. 22μm uniform films were get at the viscosity of 58.44mm2/s. And the shrink rate was 14% in the vertical direction after sintered.At last, combining material characters, wet LTCC process parameters and device structure, an EMI filter model was set up by HFSS simulation software. Helical inductance model and VIC capacitance model are introduced into the model. The HFSS software simulated materials character curves, and carried on point by point simulation. Through simulating and revising the model repeatedly, a 4.5mm×3.2mm×0.8mm low pass filter with 9 metal patterns was set up.