Research On Fabrication And Properties Of Neodymium System Microwave Dielectric Ceramic

With the rapid development of modern communication and electronic technology, the development of microwave material with moderate permittivity, high Q·f value and near zero temperature coefficient of resonant frequency τf become the key to the preparation of electronic components in miniaturization and lightweight.Conventional solid-state preparation method was used for the synthesis of Ca0.61 Ndx Ti O3 and Ca0.61 Ndx Ti O3-Mg Ti O3, and its dielectric properties were investigated. In order to adjust the microwave dielectric properties of materials, Ca0.61Nd0.36 Ti O3-Mg Ti O3 dopping with Zn Al2O4, La3+ and Nb5+ were analysised. Microstructure and phase composition were characterized by scanning electron microscopy(SEM), Energy Disperse Spectroscopy(EDS) and X-ray diffraction(XRD). The dielectric properties such as permittivity, temperature coefficient of resonant frequency τf and Q·f value were explored by using network analyzer.The results show that τf of Ca0.61 Ndx Ti O3 reduce with the increasing Nd content, and the τf is the lowest with x=0.36. After compositing Ca0.61Nd0.36 Ti O3 and Mg Ti O3, the τf was further reduced from 104 ppm/℃ to 73 ppm/℃, and then the microwave ceramic with εr=45.3, τf=73ppm/℃, Q·f =35000 was prepared.For the Zn Al2O4, La3+ and Nb5+ composite or doped Ca0.61 Ndx Ti O3-Mg Ti O3 ceramics, the τf value was further reduced and the Q·f value was improved when the condition of the permittivity was higher than 40. When Nb5+ dopping content is 0.01 and Zn Al2O4 is 0.04, the ceramic was got with εr=41, τf=40ppm/℃, Q·f=38016Sintering process showing that the ceramics have the best dielectric performance with 250℃/h heating rate and 4 hours’ holding time.