The supersaturated solution of MgO· 3B2O3 18% MgSO4 H2O was prepared and then reacted under hydrothermal condition at 120℃ . The solid phases of the different time were identified by means of chemical analysis, ...The supersaturated solution of MgO· 3B2O3 18% MgSO4 H2O was prepared and then reacted under hydrothermal condition at 120℃ . The solid phases of the different time were identified by means of chemical analysis, XRD, FT IR, SEM. The results show that the solid phases are spherical and sheet szaibelyite, which is different from those of non hydrothermal condition. On these grounds we suggested the crystallization mechanism of szaibelyite under the hydrothermal condition and then discussed the effects of hydrothermal properties on the crystallization mechanism.展开更多
The effects of CuO and H3BO3 additions on the low-temperature sintering,microstructure,and microwave dielectric properties of Ba2Ti3Nb4O18 ceramics were investigated.The addition of less amount of CuO （ 〈1 wt%） con...The effects of CuO and H3BO3 additions on the low-temperature sintering,microstructure,and microwave dielectric properties of Ba2Ti3Nb4O18 ceramics were investigated.The addition of less amount of CuO （ 〈1 wt%） considerably facilitated the densification of Ba2Ti3Nb4O18 ceramics.Appropriate addition of H3BO3 （ 〈3.5 wt%） remarkably improved the microwave dielectric properties of ceramics.The addition of H3BO3 and CuO successfully reduced the sintering temperature of Ba2Ti3Nb4O18 ceramics from 1300 to 1050 ℃.Ba2Ti3Nb4O18 ceramics sintered at 1 050 ℃ for 4 h with the addition of 1.0 wt% CuO and 3.5 wt% H3BO3 exhibited good microwave dielectric properties：er=33.74,Q？f=13 812 GHz,and tf=-5.35 ppm/°C at about 5.0 GHz.展开更多
文摘The supersaturated solution of MgO· 3B2O3 18% MgSO4 H2O was prepared and then reacted under hydrothermal condition at 120℃ . The solid phases of the different time were identified by means of chemical analysis, XRD, FT IR, SEM. The results show that the solid phases are spherical and sheet szaibelyite, which is different from those of non hydrothermal condition. On these grounds we suggested the crystallization mechanism of szaibelyite under the hydrothermal condition and then discussed the effects of hydrothermal properties on the crystallization mechanism.
文摘The effects of CuO and H3BO3 additions on the low-temperature sintering,microstructure,and microwave dielectric properties of Ba2Ti3Nb4O18 ceramics were investigated.The addition of less amount of CuO （ 〈1 wt%） considerably facilitated the densification of Ba2Ti3Nb4O18 ceramics.Appropriate addition of H3BO3 （ 〈3.5 wt%） remarkably improved the microwave dielectric properties of ceramics.The addition of H3BO3 and CuO successfully reduced the sintering temperature of Ba2Ti3Nb4O18 ceramics from 1300 to 1050 ℃.Ba2Ti3Nb4O18 ceramics sintered at 1 050 ℃ for 4 h with the addition of 1.0 wt% CuO and 3.5 wt% H3BO3 exhibited good microwave dielectric properties：er=33.74,Q？f=13 812 GHz,and tf=-5.35 ppm/°C at about 5.0 GHz.
