机械球磨时间对液相烧结Ba_2Ti_3Nb_4O_(18)陶瓷材料结构和性能的影响(英文)

EFFECT OF MECHANICAL MILLING TIME ON STRUCTURES AND PROPERTIES OF Ba_2Ti_3Nb_4O_(18) CERAMICS BY THE LIQUID-PHASE SINTERING

Ba2Ti3Nb4O18是BaO-TiO2-Nb2O5体系中一种新型的介质材料,具有优良的微波介电性能。为满足低温共烧陶瓷技术(low temperature cofired ceramics,LTCC)对微波介质陶瓷材料的低温烧结要求,实现在900℃与银电极共烧,添加了质量分数为5%的ZnO-B2O3玻璃作助融剂,并研究了机械球磨时间对粉料粒径、陶瓷样品的烧结密度、显微结构和介电性能的影响。机械球磨6h的粉体粒径适中(约90nm),用该粉料制备的陶瓷样品可以在900℃致密烧结(大于理论密度的95%),且高频介电性能为(1MHz下测试):介电常数εr≈36,介电损耗tanδ≈2×10–4,电容温度系数αc≈–2.5×10–6/℃。同时微波介电性能良好:εr=33.3,品质因数和频率的乘积Qf=14274GHz。可与银电极共烧结作为LTCC介质瓷料。

Ba2Ti3Nb4O18 is a new type of dielectric composition in the BaO-TiO2-Nb2O5 system with good microwave dielectric properties. 5% （in mass） ZnO-B2O3 frit was added to lower the sintering temperature to meet the requirement of the low temperature co-fired ceramics （LTCC） technique to be co-fired with Ag electrodes. The effect of mechanical milling time on the particle size, sintering density, microstructure and dielectric properties of Ba2Ti3Nb4O18 ceramics was studied. The particle size of the starting materials mechanically milled for 6 h is moderate （about 90 nm） and ceramic bulks could be dense sintered at 900℃ with high frequency dielectric properties （measured at 1 MHz）： dielectric constant（εr）≈36, dielectric loss （tanδ）≈2× 10^-4 and temperature coefficient of capacitance （ac）≈-2.5× 10^4/℃. The microwave dielectric properties are as follows： εr=33.3 and Qf=14274GHz. The material could be sintered with Ag electrodes and is suitable for LTCC application.