| Microwave dielectric ceramics are applied in an electric circuit of microwave and conduct a kind of or various functions. It has good function of high dielectric constant and small temperature coefficient, etc. Be suitable for to manufacture various microwave machine pieces, such the resonator filter and oscillation of electronics resist, navigates, the live television of communication, radar, household-use satellite accepts machine and mobile, can satisfy the microwave electric circuit small scaled turn, gather turn, high dependable and low cost request. The system such as BaO-TiO2, BaO-Ln2O3-TiO2 is the main research direction in many different countries now focusing on. In the mean time, there are many other MWDC systems that have a lot of prospect in microwave telecom technology. As a newly developed system, PbnNb2O5+n has got more and more attention.The research of this aspect just starts soon. Owing to the craft characteristic of this series material don't be someone carried on to study completely. In this paper, two kinds of methods are used to prepare the PbnNb2O5+n(n=1.5, 2) powder. PbO and Nb2O5 were completely milled to synthesize presursor. Product was made after heat-treat with the aftertreatment. The finished product is cubic Pb1.5Nb2O6.5 powder and tripartite Pb2Nb2O7 powder through XRD and SEM mesure. The effect of craft factor such heat treatment temperature, heat treatment time, milling time etc. on the crystalline grain grow and shap was studied through serial experiments. The suitable prepare factors were given: with no additive, the milling time is 4h; sintering temparature is 800900℃; And sintering time is 4h. After adding additives A (NaCl :KCl=1:1) and B (Na2SO4 : K2SO4= 1:1), the sintering temparature was reduced to 600℃, the size and shap were both changed in the mean time. Reaction dynamics thermodynamics and the mechanism were also analysized in the paper. Hope to be helpful for preparing microwave dielectric ceramics devices.
|
PDF Full Text Request