A technique is described for the dynamic measurement of selected thermophysical properties of electrically conducting solids in the temperature range from 1100 K to the melting point. Based on rapid resistive self-hea...A technique is described for the dynamic measurement of selected thermophysical properties of electrically conducting solids in the temperature range from 1100 K to the melting point. Based on rapid resistive self-heating of the specimen from room temperature to any desired high temperature in several seconds by the passage of an electical current pulse through it, this technique measures the pertinent quantities such as current, voltage, randiance temperature, with sub-millisecond time resolution. The pulse-heating technique is applied to strip specimens. The radiance temperature is measured by high-speed pyrometry, normal spectral emissivity of the strips is measured by integrating sphere reflectometry. The normal spectral emissivity results are used to compute the true temperature of the specimens. The heat capacity, electrical resistivity, total hemispherical emissivity are evaluated in the temperature range from 1100 K to the melting point.展开更多
Electrical conductance and temperature of electric copper busbar joints were measured under different torque moments. Experimental results show that laser surface melting can increase hardness and refine structure of ...Electrical conductance and temperature of electric copper busbar joints were measured under different torque moments. Experimental results show that laser surface melting can increase hardness and refine structure of the copper, and it does not deteriorate electric resistance. Meanwhile, the temperature of laser treated joints under electric current is slightly lower than that of original sample. Salt spray test shows that laser treated sample has better salt spray corrosion resistance than the original sample does. The electric resistance of both laser treated and original samples are increased with salt spray time. For the same salt spray time, the electric resistance of busbar joint is decreased with increasing torque moment.展开更多
基金This work was supported by the National Natural Science Foundation of China (No.50336010)the National Fund of Author of Most Excellent Doctoral Dissertation (No.199929)The authors gratefully acknowledge Dr.F.Righini,INRM,Italy,for the useful suggestions.
文摘A technique is described for the dynamic measurement of selected thermophysical properties of electrically conducting solids in the temperature range from 1100 K to the melting point. Based on rapid resistive self-heating of the specimen from room temperature to any desired high temperature in several seconds by the passage of an electical current pulse through it, this technique measures the pertinent quantities such as current, voltage, randiance temperature, with sub-millisecond time resolution. The pulse-heating technique is applied to strip specimens. The radiance temperature is measured by high-speed pyrometry, normal spectral emissivity of the strips is measured by integrating sphere reflectometry. The normal spectral emissivity results are used to compute the true temperature of the specimens. The heat capacity, electrical resistivity, total hemispherical emissivity are evaluated in the temperature range from 1100 K to the melting point.
文摘Electrical conductance and temperature of electric copper busbar joints were measured under different torque moments. Experimental results show that laser surface melting can increase hardness and refine structure of the copper, and it does not deteriorate electric resistance. Meanwhile, the temperature of laser treated joints under electric current is slightly lower than that of original sample. Salt spray test shows that laser treated sample has better salt spray corrosion resistance than the original sample does. The electric resistance of both laser treated and original samples are increased with salt spray time. For the same salt spray time, the electric resistance of busbar joint is decreased with increasing torque moment.
