Data pertaining to induction brazing of contact materials in a 3 layered sandwich structure consisting of a silver-tin oxide (Ag-SnO(II)) layer, a silver (Ag) inter-layer and a thin layer of phosphorous free braze-A4-TUD

Contact materials for electrical switch gears are widely used for connecting and disconnecting electric circuits. These contacts are two component systems, where the contact tips are brazed to the carriers prior to installation. The contacts used in the present work is a 3 layered sandwich structure consisting of a silver-tin oxide layer, a silver inter-layer and a thin layer of the braze. The carrier itself is copper-plated steel. The brazing process is accomplished by a high frequency inductive heating process. By varying the brazing parameters, namely, temperature and time, their influence on joint formation is investigated. The brazing joint of the contact tips were characterized by microscopy and physical analytical techniques. The mechanical characteristics were determined with Vickers micro-hardness. To investigate the dependence of temperature and/or time on joint formation, during induction brazing using high frequency inductive heating, experiments were carried out by setting up a proprietary brazing setup. Temperature monitoring was carried out using a pyrometer and thermocouple, placed deductively around the brazing sample to ascertain temperature variations in the brazing sample. Temperature disparities due to measurements with the pyrometer and thermocouple were also ascertained. To enable correct temperature determination using the pyrometer, the emissivity was investigated and compared with the thermocouple. Proper brazing data collection was ensured by investigating all relevant brazing parameters, namely, brazing temperature, sample heat up time, sample holding time under the specified brazing temperature and the time spent by the braze in the molten state. Scanning electron microscopy was carried out to investigate microstructural changes in the brazed joint at different brazing parameters. Optical light microscopy was used to acquire information about the layer thickness, microstructure evolution and porosity. Hardness of the individual brazed layers was assessed using Vickers Micro-hardness for different brazing parameters. EDX-SEM elemental mapping was carried out to ascertain the chemical compositional variations at the contact-carrier interface resulting from different brazing parameters. This data can be re-used for brazing experiments to ascertain the correct brazing parameters for effective brazing without the inclusion of porosity, determine the brazing parameters to monitor the increase in pore size and volume, ensure the formation of the Cu-Ag-P eutectic phase to encourage a decrease in the Phosphorus content in the joint zone, determine the temperature range for dissolution of the brittle Cu(III)P phase, and automate the brazing process by using a pyrometer to determine the brazing joint temperature.

电气开关设备用触头材料广泛用于电路的通断连接。此类触头为双组件结构，安装前需将触头钎焊至触头座上。本研究所用触头为三层夹心结构，包含银氧化锡层、银中间层与薄钎料层，触头座本身为镀铜钢材质。本次实验采用高频感应加热（high frequency inductive heating）工艺完成钎焊，通过改变钎焊参数（温度与时间），研究其对钎焊接头形成的影响。采用显微分析与物理分析技术对触头钎焊接头进行表征，并通过维氏显微硬度（Vickers micro-hardness）测试获取其力学性能。为探究高频感应钎焊过程中温度与/或时间对钎焊接头形成的影响，本研究搭建专用钎焊装置开展实验。采用高温计（pyrometer）与热电偶（thermocouple）合理布置于钎焊样品周边，以监测样品的温度变化。同时，还评估了高温计与热电偶的测量温差。为确保通过高温计准确测定温度，本研究对其发射率（emissivity）进行了探究，并与热电偶的测量结果进行对比。通过对所有相关钎焊参数开展系统性研究，确保采集到准确的钎焊数据，这些参数包括钎焊温度、样品升温时长、指定钎焊温度下的保温时长，以及钎料处于熔融状态的持续时间。采用扫描电子显微镜（Scanning Electron Microscopy, SEM）分析不同钎焊参数下钎焊接头的微观结构演变；利用光学显微镜获取各层厚度、微观组织演变与孔隙率相关信息；针对不同钎焊参数下各钎焊层的硬度，采用维氏显微硬度（Vickers micro-hardness）进行测试评估；通过EDX-SEM元素面分布表征，分析不同钎焊参数下触头与触头座界面处的化学成分变化。本数据集可复用于钎焊实验研究，具体可实现以下目标：确定无孔隙高效钎焊的最优工艺参数；监测孔隙尺寸与体积的增长规律；明确可促进接头区域磷含量降低的Cu-Ag-P共晶相（eutectic phase）形成条件；确定脆性Cu(III)P相的溶解温度区间；以及通过高温计测定钎焊接头温度，实现钎焊工艺自动化。