本文用 Van der pauw 法在77～300k 的温度范围内测试了 CdTe∶Al 材料的霍尔电学特性。实验测得 Al 杂质施主能级为0.010eV,最大霍尔迁移率为1.8×10~3cm^2/V·s,实验结果表明高掺杂样品中存在明显的“离化杂质浓度效应”。文...本文用 Van der pauw 法在77～300k 的温度范围内测试了 CdTe∶Al 材料的霍尔电学特性。实验测得 Al 杂质施主能级为0.010eV,最大霍尔迁移率为1.8×10~3cm^2/V·s,实验结果表明高掺杂样品中存在明显的“离化杂质浓度效应”。文中还讨论了 CdTe∶Al 中的杂质补偿问题以及载流子的散射机理,并给出了霍尔系数、迁移率等有关参数与温度的关系。展开更多
The existence of inclusion influences the properties of aluminum alloy castings,from which the castings will face scrapping under severe condition.Great efforts on the inclusions in aluminum alloy were made and many i...The existence of inclusion influences the properties of aluminum alloy castings,from which the castings will face scrapping under severe condition.Great efforts on the inclusions in aluminum alloy were made and many inclusion assessment methods were put forward.However,most of the current methods are characterized by time consuming and expensive equipment cost,which limits the application in aluminum industry.Since the aluminum properties are sensitive to the inclusion,this paper tries to establish a new kind of inclusion assessment method.The inclusions were introduced to aluminum melts by adding aluminum scraps.The samples with different inclusion contents were prepared.The microstructure contained inclusions was observed.The inclusion was automatically identified with an image analyzer by setting different grey threshold value,and the inclusion content was obtained.The image analysis shows that inclusions wreck the continuity of the alloy matrix seriously,and the inclusion area percentage increases with the increasing of aluminum scraps.The high and low polarization measurements were conducted in 3.5 wt%NaCl aqueous solution at the temperature of 25℃.The electrochemical parameters of the testing materials,such as corrosion potential E k,corrosion current density I k and the linear polarization resistance R p,were obtained.The polarization measurement results show that the linear polarization resistances decrease,the corrosion potentials move towards more negative direction,and the corrosion current densities increase with the increasing of inclusion content.The theoretical analysis of the inclusion content and the corrosion current density was performed.The existence of inclusions makes the microstructure form corrosion microcells between the alloy matrix and inclusions.The impressed current can accelerate the current velocity or corrosion current density.The regression model of the inclusion contents vs.the corrosion current density was obtained.This model can be used to quantitatively analyze the inclusion content in aluminum alloys on the basis of inclusion sensitivity to the inclusion content.It is confirmed that the electrochemical method for inclusion assessment(EcMIA)is simple and reliable,which can provide a new solution for inclusion assessment in aluminum alloy.展开更多
文摘本文用 Van der pauw 法在77～300k 的温度范围内测试了 CdTe∶Al 材料的霍尔电学特性。实验测得 Al 杂质施主能级为0.010eV,最大霍尔迁移率为1.8×10~3cm^2/V·s,实验结果表明高掺杂样品中存在明显的“离化杂质浓度效应”。文中还讨论了 CdTe∶Al 中的杂质补偿问题以及载流子的散射机理,并给出了霍尔系数、迁移率等有关参数与温度的关系。
基金supported by National Natural Science Foundation of China(Grant No.50864002)Guangxi Provincial Natural Science Foundation of China(Grant No.0991001)Natural Science Foundation of Guangxi University of China(Grant No.X071081)
文摘The existence of inclusion influences the properties of aluminum alloy castings,from which the castings will face scrapping under severe condition.Great efforts on the inclusions in aluminum alloy were made and many inclusion assessment methods were put forward.However,most of the current methods are characterized by time consuming and expensive equipment cost,which limits the application in aluminum industry.Since the aluminum properties are sensitive to the inclusion,this paper tries to establish a new kind of inclusion assessment method.The inclusions were introduced to aluminum melts by adding aluminum scraps.The samples with different inclusion contents were prepared.The microstructure contained inclusions was observed.The inclusion was automatically identified with an image analyzer by setting different grey threshold value,and the inclusion content was obtained.The image analysis shows that inclusions wreck the continuity of the alloy matrix seriously,and the inclusion area percentage increases with the increasing of aluminum scraps.The high and low polarization measurements were conducted in 3.5 wt%NaCl aqueous solution at the temperature of 25℃.The electrochemical parameters of the testing materials,such as corrosion potential E k,corrosion current density I k and the linear polarization resistance R p,were obtained.The polarization measurement results show that the linear polarization resistances decrease,the corrosion potentials move towards more negative direction,and the corrosion current densities increase with the increasing of inclusion content.The theoretical analysis of the inclusion content and the corrosion current density was performed.The existence of inclusions makes the microstructure form corrosion microcells between the alloy matrix and inclusions.The impressed current can accelerate the current velocity or corrosion current density.The regression model of the inclusion contents vs.the corrosion current density was obtained.This model can be used to quantitatively analyze the inclusion content in aluminum alloys on the basis of inclusion sensitivity to the inclusion content.It is confirmed that the electrochemical method for inclusion assessment(EcMIA)is simple and reliable,which can provide a new solution for inclusion assessment in aluminum alloy.
