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

0.65CaTiO3–0.35Sm0.9Nd0.1AlO3 (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 0.65CaTiO3–0.35Sm0.9Nd0.1AlO3 powders with particle size of 30–40 nm were obtained by calcination at 800 °C. Dense ceramic was successfully obtained from the ultrafine powders sintered at 1,325 °C, almost 100 °C lower than 1,415 °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 er ~ 39, Q × f over 50,000 GHz and small τf ~ −7.1 ppm/K.