Improvement on the characteristic of Ba2Ti9O20 microwave dielectric materials prepared by modified co-precipitation method

Modified co-precipitation process (MCP), which combines the automatic pH value control system and supersonic spraying of co-precipitants, was used to synthesize nano-sized Ba2Ti9O20 precursors (48.8 nm). Kinetics for crystallization process is markedly enhanced when the O2 atmosphere was used to replace for air atmosphere in the calcinations and sintering processes. High-density Ba2Ti9O20 materials (>94% T.D.), possessing good microwave properties (K = 38.7 and Q × f = 30,502 GHz), can be obtained by sintering the sample at 1200 °C for 4 h in O2 atmosphere, which is lower than the sintering temperature needed when the materials were processed in air or N2 atmosphere (i.e., 1250 °C for 4 h).