| MnZn ferrite materials are extensively applied in telecommunications, cars, industry, military affairs and space navigation etc. With the trend of modern electronic applications towards optimum properties, high density and high reliability, LTCC technology is paid more attention to being an hotspot. Due to co-fired request of inside electrode, it is required to control sintering temperarture of LTCC technology less than 900℃. For one of important component, sintering temperarture of LTCC technology will be also controlled less than 900℃. Liquid phase method prepared nanopowders and added additives is used to lower sintering temperarture in this paper.Firstly, Soft magnetic MnZn ferrite nanoparticles were prepared by a novel sol-gel auto-combustion method using Mn(NO3)2,Fe(NO3)3·9H2O and Zn(NO3)2·6H2O as a starting materials dissolved in water and citric acid. The powder was charactered by X-ray diffraction analysis and transmission electron Microscope (TEM) method. The effects of process and powders structure were further studied, considering and analyzing raw materials, complexing agent, pH value, concentration, heat treatment.Secondly, Soft magnetic MnZn ferrite powders were washed repeatedly by alcohol, then groud, dried, made grains and pressed into wafer. At 850~950℃, Mn0.5Zn0.5Fe2O4+xBi2O3/CuO/(CuO·Bi2O3) (where x=0~8wt%) ferrites were prepared under low temperatures. The effects of on phase formation, densification process, and magnetic properties were further studied by scanning electron microscope (SEM) and vibrating samples magnetometer (VSM).The experimental results show that sintering temperature of pure MnZn-ferrite is only 930℃. An appropriate amount of Bi2O3 can lower the sintering temperature obviously to 850°C but sacrifice the magnetic property. An appropriate amount of CuO and CuO-Bi2O3 can also lower the sintering temperature below 900°C and improve the magnetic property which high values of the permeability and the saturation magnetization are 188 and 60.09 emu.g-1 respectively. Thus CuO-Bi2O3 is subsequently evaluated for its contribution to lower the sintering temperature and improve the magnetic property of MnZn-ferrites. |
