The magnesium alloys are considered to be the best structural materials,because of their advantageous weight to strength ratio.But,the limitation in their real field applications lies on the fact that magnesium alloys...The magnesium alloys are considered to be the best structural materials,because of their advantageous weight to strength ratio.But,the limitation in their real field applications lies on the fact that magnesium alloys are highly susceptible for corrosion.The corrosion behaviour of AZ31 alloy was investigated by electrochemical methods in sodium chloride and sodium sulphate of different concentrations at different temperatures.The corrosion rate was monitored by potentiodynamic polarization technique and electrochemical impedance spectroscopy method.The surface morphology and surface composition of the freshly polished surface of the alloy was compared with that of the corroded surface by recording their SEM images and EDS,respectively.The results showed that the corrosion rate of AZ31 alloy increased with the increase in the temperature of the medium and also with the increase in the salt concentration of the medium.The activation parameters for the corrosion process were calculated and interpreted.展开更多
The cavity ring-down(CRD) technique is adopted for simultaneously measuring s-and p-polarization reflectivity of highly reflective coatings without employing any polarization optics. As the s-and p-polarized light tra...The cavity ring-down(CRD) technique is adopted for simultaneously measuring s-and p-polarization reflectivity of highly reflective coatings without employing any polarization optics. As the s-and p-polarized light trapped in the ring-down cavity decay independently, with a randomly polarized light source the ring-down signal recorded by a photodetector presents a double-exponential waveform consisting of ring-down signals of both s-and p-polarized light. The s-and p-polarization reflectivity values of a test mirror are therefore simultaneously determined by fitting the recorded ring-down signal with a double-exponential function. The determined s-and p-polarization reflectivity of 30° and 45° angle of incidence mirrors are in good agreement with the reflectivity values measured with the conventional CRD technique employing a polarizer for polarization control.展开更多
文摘The magnesium alloys are considered to be the best structural materials,because of their advantageous weight to strength ratio.But,the limitation in their real field applications lies on the fact that magnesium alloys are highly susceptible for corrosion.The corrosion behaviour of AZ31 alloy was investigated by electrochemical methods in sodium chloride and sodium sulphate of different concentrations at different temperatures.The corrosion rate was monitored by potentiodynamic polarization technique and electrochemical impedance spectroscopy method.The surface morphology and surface composition of the freshly polished surface of the alloy was compared with that of the corroded surface by recording their SEM images and EDS,respectively.The results showed that the corrosion rate of AZ31 alloy increased with the increase in the temperature of the medium and also with the increase in the salt concentration of the medium.The activation parameters for the corrosion process were calculated and interpreted.
文摘The cavity ring-down(CRD) technique is adopted for simultaneously measuring s-and p-polarization reflectivity of highly reflective coatings without employing any polarization optics. As the s-and p-polarized light trapped in the ring-down cavity decay independently, with a randomly polarized light source the ring-down signal recorded by a photodetector presents a double-exponential waveform consisting of ring-down signals of both s-and p-polarized light. The s-and p-polarization reflectivity values of a test mirror are therefore simultaneously determined by fitting the recorded ring-down signal with a double-exponential function. The determined s-and p-polarization reflectivity of 30° and 45° angle of incidence mirrors are in good agreement with the reflectivity values measured with the conventional CRD technique employing a polarizer for polarization control.
