Spelling suggestions: "subject:"siliciumlegierung"" "subject:"siliziumlegierung""
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Selbstdiffusion in Silizium-Germanium-LegierungenStrohm, Andreas. Unknown Date (has links) (PDF)
Universiẗat, Diss., 2002--Stuttgart.
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Instationäre Erstarrung eutektischer Al-Si-LegierungenSous, Stephan. Unknown Date (has links) (PDF)
Techn. Hochsch., Diss., 2000--Aachen.
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Heterojunction solar cells (a-Si, c-Si) investigations on PECV deposited hydrogenated silicon alloys for use as high quality surface passivation and emitter, BSFMüller, Thomas January 2009 (has links)
Zugl.: Hagen, Univ., Diss., 2009
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Microscopic structural and electrochemical aspects of Al-Mg-Si corrosionEckermann, Fabian January 2008 (has links)
Zugl.: Zürich, Techn. Hochsch., Diss., 2008
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Strukturelle Charakterisierung und Optimierung der Beugungseigenschaften von Si1-xGex-Gradientenkristallen, die aus der Gasphase gezogen wurdenLiß, Klaus-Dieter. Unknown Date (has links) (PDF)
Techn. Hochsch., Diss., 1994--Aachen.
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Grain refinement in hypoeutectic Al-Si alloy driven by electric currentsZhang, Yunhu 26 February 2016 (has links) (PDF)
The present thesis investigates the grain refinement in solidifying Al-7wt%Si hypoeutectic alloy driven by electric currents. The grain size reduction in alloys generated by electric currents during the solidification has been intensively investigated. However, since various effects of electric currents have the potential to generate the finer equiaxed grains, it is still argued which effect plays the key role in the grain refinement process. In addition, the knowledge about the grain refinement mechanism under the application of electric currents remains fragmentary and inconsistent. Hence, the research objectives of the present thesis focus on the role of electric current effects and the grain refinement mechanism under the application of electric currents.
Chapter 1 presents an introduction with respect to the subject of grain refinement in alloys driven by electric current during the solidification process in particular, including the research objectives; the research motivation; a brief review about the research history; a short introduction on the electric currents effects and a review relevant to the research status of grain refinement mechanism.
Chapter 2 gives a description of research methods. This chapter shows the employed experiment materials, experimental setup, experimental procedure, the analysis methods of solidified samples, and numerical method, respectively.
Chapter 3 focuses on the role of electric current effects in the grain refinement process. A series of solidification experiments are performed under various values of effective electric currents for both, electric current pulse and direct current. The corresponding temperature measurements and flow measurements are carried out with the increase of effective electric current intensity. Meanwhile, numerical simulations are conducted to present the details of the flow structure and the distribution of electric current density and electromagnetic force. Finally, the role of electric current effects is discussed to find the key effect in the grain refinement driven by electric currents.
Chapter 4 investigates the grain refinement mechanism driven by electric currents. This chapter mainly focuses on the origin of finer equiaxed grain for grain refinement under the application of electric current on account of the importance of the origin for understanding the grain refinement mechanism. A series of solidification experiments are carried out in Al-7wt%Si alloy and in high purity aluminum. The main origin of equiaxed grain for grain refinement is concluded based on the experiment results.
Chapter 5 presents three further investigations based on the achieved knowledge in chapter 3 and 4 about the role of electric current effects and the grain refinement mechanism. According to the insight into the key electric current effect for the grain refinement shown in chapter 3, this chapter presents a potential approach to promote the grain refinement. In addition, the solute distribution under the influence of electric current is examined based on the knowledge about the electric current effects. Moreover, the grain refinement mechanism under application of travelling magnetic field is investigated by performing a series of solidification experiments to compare with the experiments about the grain refinement mechanism driven by electric currents shown in chapter 4.
Chapter 6 summarizes the main conclusions from the presented work.
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Grain refinement in hypoeutectic Al-Si alloy driven by electric currentsZhang, Yunhu 19 February 2016 (has links)
The present thesis investigates the grain refinement in solidifying Al-7wt%Si hypoeutectic alloy driven by electric currents. The grain size reduction in alloys generated by electric currents during the solidification has been intensively investigated. However, since various effects of electric currents have the potential to generate the finer equiaxed grains, it is still argued which effect plays the key role in the grain refinement process. In addition, the knowledge about the grain refinement mechanism under the application of electric currents remains fragmentary and inconsistent. Hence, the research objectives of the present thesis focus on the role of electric current effects and the grain refinement mechanism under the application of electric currents.
Chapter 1 presents an introduction with respect to the subject of grain refinement in alloys driven by electric current during the solidification process in particular, including the research objectives; the research motivation; a brief review about the research history; a short introduction on the electric currents effects and a review relevant to the research status of grain refinement mechanism.
Chapter 2 gives a description of research methods. This chapter shows the employed experiment materials, experimental setup, experimental procedure, the analysis methods of solidified samples, and numerical method, respectively.
Chapter 3 focuses on the role of electric current effects in the grain refinement process. A series of solidification experiments are performed under various values of effective electric currents for both, electric current pulse and direct current. The corresponding temperature measurements and flow measurements are carried out with the increase of effective electric current intensity. Meanwhile, numerical simulations are conducted to present the details of the flow structure and the distribution of electric current density and electromagnetic force. Finally, the role of electric current effects is discussed to find the key effect in the grain refinement driven by electric currents.
Chapter 4 investigates the grain refinement mechanism driven by electric currents. This chapter mainly focuses on the origin of finer equiaxed grain for grain refinement under the application of electric current on account of the importance of the origin for understanding the grain refinement mechanism. A series of solidification experiments are carried out in Al-7wt%Si alloy and in high purity aluminum. The main origin of equiaxed grain for grain refinement is concluded based on the experiment results.
Chapter 5 presents three further investigations based on the achieved knowledge in chapter 3 and 4 about the role of electric current effects and the grain refinement mechanism. According to the insight into the key electric current effect for the grain refinement shown in chapter 3, this chapter presents a potential approach to promote the grain refinement. In addition, the solute distribution under the influence of electric current is examined based on the knowledge about the electric current effects. Moreover, the grain refinement mechanism under application of travelling magnetic field is investigated by performing a series of solidification experiments to compare with the experiments about the grain refinement mechanism driven by electric currents shown in chapter 4.
Chapter 6 summarizes the main conclusions from the presented work.:Abstract VII
Contents IX
List of figures XI
List of tables XVII
1. Introduction 1
1.1 Research objectives 1
1.2 Research motivation 2
1.3 Research history 5
1.4 Electric currents effects 9
1.4.1 Some fundamentals 10
1.4.2 Role of electric currents effects in grain refinement 12
1.5 Grain refinement mechanism 13
1.5.1 Nucleation theory 13
1.5.2 Equiaxed grain formation without the application of external fields 18
1.5.3 Grain refinement mechanism under the application of electric currents 23
1.5.4 Grain refinement mechanism under the application of magnetic field 29
2. Research methods 31
2.1 Introduction 31
2.2 Experimental materials 31
2.2.1 Solidification 31
2.2.2 Similarity of GaInSn liquid metal and Al-Si melt 32
2.3 Experimental setup 33
2.3.1 Solidification 33
2.3.2 Flow measurements 35
2.3.3 External energy fields 36
2.4 Experimental procedure 38
2.4.1 Solidification 38
2.4.2 Flow measurements 39
2.5 Metallography 39
2.6 Numerical method 41
2.6.1 Numerical model 41
2.6.2 Numerical domain and boundary conditions 42
3. Role of electric currents effects in the grain refinement 45
3.1 Introduction 45
3.2 Experimental parameter 45
3.3 Results 46
3.3.1 Solidified structure 46
3.3.2 Forced melt flow 50
3.3.3 Temperature distribution 58
3.4 Discussion 61
3.5 Conclusions 67
4. Grain refinement mechanism driven by electric currents 69
4.1 Introduction 69
4.2 Experimental parameter 69
4.3 Results 73
4.3.1 Solidified structure of Al-Si alloy 73
4.3.2 Cooling curves of Al-Si alloy 77
4.3.3 Solidified structure of high purity aluminum 78
4.4 Discussion 80
4.5 Conclusions 83
5. Supplemental investigations 85
5.1 A potential approach to improve the grain refinement 85
5.1.1 Introduction 85
5.1.2 Experimental parameter 86
5.1.3 Results and discussion 87
5.2 Macrosegregation formation 90
5.2.1 Introduction 90
5.2.2 Experimental parameter 91
5.2.3 Results and discussion 92
5.3 Grain refinement driven by TMF 97
5.3.1 Introduction 97
5.3.2 Experimental parameter 97
5.3.3 Results and discussion 98
5.4 Conclusions 102
6. Summary 103
Bibliography 105
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All AlSi-wired solar cell: A way to avoid silver and copper in solar module fabricationMüller, Matthias 29 February 2024 (has links)
PV solar cells and modules have to show high-efficiency at very low cost. The idea of the project is to understand and test the feasibility of an all-aluminum-silicon (AlSi)-wired solar cell and solar module enabling an easy cell string for module assembly. The cell is thought to be build up in the best case by a silicon wafer cleaned and passivated by dielectric layer which will be laser opened in lines or dashes or dots for contacting. The AlSi wires are used to contact the opened areas during high temperature treatment forming contacts to silicon with local doping. The main advantage of the concept is a much cheaper cell and module fabrication as a silver- and diffusion-doping-free solar cell is build, cell contacting and module cell string connection could be one process step (i.e. no paste screen-printing and no additional stringing), thus no copper nor silver is used. Solar cell structures of interest have to withstand the eutectic temperature of silicon, thus industrial PERC and TOPCon could be possible candidates.
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