纳米MgNb_2O_6微波介质陶瓷粉体制备及表征

Preparation and Characterization of Nano-crystalline MgNb_2O_6 Microwave Dielectric Powder

微波介质陶瓷是指应用于微波频段（0．3-3000GHz）电路中作为介质材料并完成一种或多种功能的陶瓷．它不仅可以作为微波电路中的绝缘基片材料．也是制造微波介质滤波器和谐振器的关键材料。无线通信技术在微波频段的迅速发展．对微波介质陶瓷提出了更高的要求。作为一种有效的介质谐振材料，它应该具有低微波损耗、高介电常数和小的频率温度系数．

Nano-crystalline MgNb2O6 was prepared using Mg（NO3）2·6H2O, Nb2O5, HF and citric acid as raw materials by auto-ignition route. The process involves the formation of a viscous gel by thermal dehydration of the citrate-nitrate solution at about 80 ℃ The auto-ignition （at about 200 ℃） of the gel resulted in a high reactivity powder containing intimate blending of MgNbF7 and NbF3. The crystalline phase of MgNb2O6 could be formed easily at 700 ℃, which is 400 ℃ lower than that of common solid-state reaction process. The nano-crystalline MgNb2O6 （-30 nm） powder with good dispersity could be obtained at 850 ℃.