We firstly performed the reactive air wetting and brazing of Al_(2)O_(3) ceramics using Ag-(0.5-12)Nb_(2)O_(5) fillers,where Nb_(2)O_(5) can react with liquid Ag and O2 from air to generate AgNbO_(3).The contact angle...We firstly performed the reactive air wetting and brazing of Al_(2)O_(3) ceramics using Ag-(0.5-12)Nb_(2)O_(5) fillers,where Nb_(2)O_(5) can react with liquid Ag and O2 from air to generate AgNbO_(3).The contact angle of the Ag-Nb_(2)O_(5)/Al_(2)O_(3) system almost linearly decreases from~71.6°to 32.5°with the Nb_(2)O_(5) content increasing,and the joint shear strength reaches the maximum of~65.1 MPa while employing the Ag-4Nb_(2)O_(5) filler,which are mainly related to the formation and distribution of the AgNbO_(3) phase at the interface.Moreover,the interfacial bonding and electronic properties of related interfaces were investigated by first-principles calculations.The calculated works of adhesion(Wa)of Ag(111)/Ag-O-AgNbO_(3)(001)and AgNbO_(3)(001)/Al_(2)O_(3)(100)interfaces are higher than that of the Ag(111)/Al_(2)O_(3)(110)interface,indicating good reliability of the Ag/AgNbO_(3)/Al_(2)O_(3) structure.The relatively large interfacial charge transfer indicates the formation of Ag-Ag,Al-O,and Ag-O bonds in the Ag/AgNbO_(3)/Al_(2)O_(3) structure,which can contribute to the interfacial bonding.展开更多
Alumina specimens were joined together with thin aluminium interlayer at 750 and 900°C under different applied pressures and holding time in air. Flexural strength of the joints was then measured using a standard...Alumina specimens were joined together with thin aluminium interlayer at 750 and 900°C under different applied pressures and holding time in air. Flexural strength of the joints was then measured using a standard four-point bend test method. Characterization of the interface was carried out to correlate the increase in flexural strength with the applied pressure, holding temperature and time. The study showed that the strength of joint is affected by all three parameters, i.e., processing temperature, holding time as well as applied pressure.展开更多
基金supported by National Natural Science Foundation of China(Nos.52002153 and 51572112)Postdoctoral Science Foundation of China(No.2021M701470)+1 种基金Qing Lan Project[(2016)15]of jiangsu ProvinceInnovation/Entrepreneurship Program(No.JSSCTD202146)of Jiangsu Province.
文摘We firstly performed the reactive air wetting and brazing of Al_(2)O_(3) ceramics using Ag-(0.5-12)Nb_(2)O_(5) fillers,where Nb_(2)O_(5) can react with liquid Ag and O2 from air to generate AgNbO_(3).The contact angle of the Ag-Nb_(2)O_(5)/Al_(2)O_(3) system almost linearly decreases from~71.6°to 32.5°with the Nb_(2)O_(5) content increasing,and the joint shear strength reaches the maximum of~65.1 MPa while employing the Ag-4Nb_(2)O_(5) filler,which are mainly related to the formation and distribution of the AgNbO_(3) phase at the interface.Moreover,the interfacial bonding and electronic properties of related interfaces were investigated by first-principles calculations.The calculated works of adhesion(Wa)of Ag(111)/Ag-O-AgNbO_(3)(001)and AgNbO_(3)(001)/Al_(2)O_(3)(100)interfaces are higher than that of the Ag(111)/Al_(2)O_(3)(110)interface,indicating good reliability of the Ag/AgNbO_(3)/Al_(2)O_(3) structure.The relatively large interfacial charge transfer indicates the formation of Ag-Ag,Al-O,and Ag-O bonds in the Ag/AgNbO_(3)/Al_(2)O_(3) structure,which can contribute to the interfacial bonding.
文摘Alumina specimens were joined together with thin aluminium interlayer at 750 and 900°C under different applied pressures and holding time in air. Flexural strength of the joints was then measured using a standard four-point bend test method. Characterization of the interface was carried out to correlate the increase in flexural strength with the applied pressure, holding temperature and time. The study showed that the strength of joint is affected by all three parameters, i.e., processing temperature, holding time as well as applied pressure.
