Synthesis and characterization of CaTiO3-(Sm,Nd)AlO3 microwave ceramics via sol-gel method

0.65CaTiO(3)-0.35Sm(0.9)Nd(0.1)AlO(3) (CTSA) ceramic nanopowders were synthesized via sol-gel method using the ethylene diamine tetraacetic acid as a chelating agent. Thermal analysis, Fourier transform infrared spectroscopy and X-ray diffraction were used to character the decomposition of precursor and phase transformation process of derived oxide powders. Single phase and well-crystallized 0.65CaTiO(3)-0.35Sm(0.9)Nd(0.1)AlO(3) powders with particle size of 30-40 nm were obtained by calcination at 800 degrees C. Dense ceramic was successfully obtained from the ultrafine powders sintered at 1,325 degrees C, almost 100 degrees C lower than 1,415 degrees C required for conventional powders. Compared with those prepared by conventional solid-state method, the CTSA ceramics derived from sol to gel process sintered at a lower temperature showed better microwave dielectric properties of epsilon(r) similar to 39, Q x f over 50,000 GHz and small tau(f) similar to -7.1 ppm/K.