The properties of the joints are dictated by the nature, distribution, and morphology of the phases formed at the interface. The mechanical properties of brazed joints are well documented in the literature, contrarily...The properties of the joints are dictated by the nature, distribution, and morphology of the phases formed at the interface. The mechanical properties of brazed joints are well documented in the literature, contrarily to their electrochemical behaviour. Thus, the main objective of this study was to understand the influence of the phases formed at the interface on the corrosion behaviour of commercially pure Ti brazed joints, produced by using TiCuNi, eutectic Ag Cu, and Ag filler foils. The electrochemical behaviour of the Ti joints was accessed by open circuit potential and potentiodynamic polarization tests in phosphate buffer saline solution electrolyte at body temperature. Results showed that Ag-based fillers induced susceptibility to micro-galvanic corrosion between the Ag-rich and Ti phases formed at the interface and commercially pure Ti base metal. However, no significant differences were observed between the joint system and the base material when brazing with TiCuNi filler.展开更多
In this work, gallium phosphide thin films were deposited on glass substrates by radio frequency （RF） magnetron sputtering technique under different depositions conditions. The X-ray diffraction analysis showed a di...In this work, gallium phosphide thin films were deposited on glass substrates by radio frequency （RF） magnetron sputtering technique under different depositions conditions. The X-ray diffraction analysis showed a diversity of states： from amorphous in the films deposited at 175 ~C to a nearly stoichiometric and polycrystalline films, exhibiting cubic phase with preferred orientation along （220）, in the films deposited at temperatures higher than 250 ~C. Scanning electron microscopy images revealed that all films were uniform with a smooth surface, while the energy-dispersive spectroscopy （EDS） analysis showed that there was a visible dependence on the Ga/P ratio in the deposition conditions and confirmed that a residual Ga metallic phase was presented in the surface of all the films. The Raman analysis showed the structural evolution of the GaP films was strongly dependent on the deposition conditions. The conductivity of the films was slightly dependent on the argon pressure and the rf power, but strongly dependent on the deposition temperature, mainly above 200 ~C. The optical transmission and absorption analyses of the GaP films revealed an indirect band gap of ~ 1.70 eV in the films deposited at temperatures less than 200 ~C, which transited to a band gap of 2.26 eV as the deposition temperature was close to 300 ~C.展开更多
基金supported by Portuguese FCT,under the reference project UIDB/04436/2020 and M-ERA-NET/0001/2015 project。
文摘The properties of the joints are dictated by the nature, distribution, and morphology of the phases formed at the interface. The mechanical properties of brazed joints are well documented in the literature, contrarily to their electrochemical behaviour. Thus, the main objective of this study was to understand the influence of the phases formed at the interface on the corrosion behaviour of commercially pure Ti brazed joints, produced by using TiCuNi, eutectic Ag Cu, and Ag filler foils. The electrochemical behaviour of the Ti joints was accessed by open circuit potential and potentiodynamic polarization tests in phosphate buffer saline solution electrolyte at body temperature. Results showed that Ag-based fillers induced susceptibility to micro-galvanic corrosion between the Ag-rich and Ti phases formed at the interface and commercially pure Ti base metal. However, no significant differences were observed between the joint system and the base material when brazing with TiCuNi filler.
基金supported by the ERDF (European Regional Development Fund) through the COMPETE Programme (operational programme for competitiveness)by the Portuguese National Strategic Reference Framework (NSRF) through the project CFC-5568
文摘In this work, gallium phosphide thin films were deposited on glass substrates by radio frequency （RF） magnetron sputtering technique under different depositions conditions. The X-ray diffraction analysis showed a diversity of states： from amorphous in the films deposited at 175 ~C to a nearly stoichiometric and polycrystalline films, exhibiting cubic phase with preferred orientation along （220）, in the films deposited at temperatures higher than 250 ~C. Scanning electron microscopy images revealed that all films were uniform with a smooth surface, while the energy-dispersive spectroscopy （EDS） analysis showed that there was a visible dependence on the Ga/P ratio in the deposition conditions and confirmed that a residual Ga metallic phase was presented in the surface of all the films. The Raman analysis showed the structural evolution of the GaP films was strongly dependent on the deposition conditions. The conductivity of the films was slightly dependent on the argon pressure and the rf power, but strongly dependent on the deposition temperature, mainly above 200 ~C. The optical transmission and absorption analyses of the GaP films revealed an indirect band gap of ~ 1.70 eV in the films deposited at temperatures less than 200 ~C, which transited to a band gap of 2.26 eV as the deposition temperature was close to 300 ~C.
