Investigation On Hydrothermal-solid Phase Method And Low Temperature Sintering Of ZnO-1.1TiO₂ Microwave Dielectric Ceramics

As the rapid development of microwave technology, high performance microwave dielectric ceramics, which can be sintered at low temperature, are required by the microminiaturization of components. In order to fulfill these requirements, design and manufacture of multi-chip microwave components using low temperature cofired ceramics technology has become a research hotspot now. LTCC by its excellent electronic, machinery, thermal properties, has become the electronic components intergrated,modular preferred way, in the global development of rapid,widely used for substrate,packaging,and microwave devices and other fields.ZnTiO3 ceramics behaves high dielectric constant, low dielectric loss and stable temperature coefficient of resonant frequency, if can improve the thermal stability ZnTiO3 and with the LTCC technology manufacture craft match, will be the ideal LTCC dielectric materials.In this thesis,ZnO-TiO2 composite oxide were prepared by hydrothermal method, and synthesizes ZnO-1.1TiO2 take this as raw material through conventional mixed-oxide method. It has been found experimentally that calcining the powder at different temperature after hydrothermal reaction at 180℃,8h and volumetric rate of 80%,the optimum synthesis temperature of zinc titanate was 800～850℃. Zinc titanium ceramic densification behavior mainly occurred in the 1020～1070℃.On this basis, doped separately with V2O5-Bi2O3(hereinafter designated as VB) , CuO-V2O5 ( hereinafter designated as CV ) and CuO-V2O5-Bi2O3 ( hereinafter designated as CVB), thermal, microstructural and microwave dielectric properties of the hexagonal phase ZnTiO3 prepared were characterized or measured by means of XRD,SEM. As a result, ZnO-1.1TiO2 ceramics doped with V2O5-Bi2O3, its temperature coefficient of resonant frequency curve through zero, The dielectric properties of samples with 0.5wt% VB addition were:εr≈25.3,Qf≈20860GHz,τf≈+2ppm/℃.CuO or V2O5 addition have not affect the phase composition of zinc titanate ceramics, the dielectric properties of samples sintered at 870℃with CV addition were:εr≈28,Qf≈20000GHz,τf≈+6ppm/℃. Ilmenite phase did inhibit the decomposition with the addition of CuO-V2O5-Bi2O3,showing a very good effect of lowering sintering temperature. With 2wt% CVB addition,the ceramics sintered at 830℃get a relative density value of 98.8%,and microwave dielectric properties:εr=30,Qf=33460GHz,τf=6ppm/℃.