Sr0.9Ba0.1Ti0.8Nb0.2O3 ceramics （x=0, 0.01, 0.02 and 0.05） are prepared by solid state reaction, whose thermoelectric properties are investigated from 323K to 1073K. By introducing A-site nonstoichiometry, the absol...Sr0.9Ba0.1Ti0.8Nb0.2O3 ceramics （x=0, 0.01, 0.02 and 0.05） are prepared by solid state reaction, whose thermoelectric properties are investigated from 323K to 1073K. By introducing A-site nonstoichiometry, the absolute Seebeck coefficient is enhanced, while the electrical resistivity is surprisingly reduced due to the significantly enhanced carrier mobility. These results are dramatic in thermoelectric materials, effectively enhancing the power factor. Moreover, the thermal conductivity is reduced, thus the thermoelectric performance of Sr0.9Ba0.1Ti0.8Nb0.2O3 ceramic is significantly enhanced by A-site nonstoiehiometry.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
基金Supported by the National Basic Research Program of China under Grant No 2013CB632506the National Natural Science Foundation of China under Grant Nos 51202132,51002087 and 11374186the Independent Innovation Foundation of Shandong University under Grant No IIFSDU 2012TS028
文摘Sr0.9Ba0.1Ti0.8Nb0.2O3 ceramics （x=0, 0.01, 0.02 and 0.05） are prepared by solid state reaction, whose thermoelectric properties are investigated from 323K to 1073K. By introducing A-site nonstoichiometry, the absolute Seebeck coefficient is enhanced, while the electrical resistivity is surprisingly reduced due to the significantly enhanced carrier mobility. These results are dramatic in thermoelectric materials, effectively enhancing the power factor. Moreover, the thermal conductivity is reduced, thus the thermoelectric performance of Sr0.9Ba0.1Ti0.8Nb0.2O3 ceramic is significantly enhanced by A-site nonstoiehiometry.
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.
