利用电火花线切割的方法在3种材质的坩埚，分别为MgO、MgO-Spinel和Al2O3，中心高度位置取样。将样品进行镶样、粗磨、细磨、抛光，样品的显微组织在ZEISS Sigma 300场发射扫描电镜进行观察，同时测量样品的EDS。真空感应熔炼实验结束后，在每炉实验的坩埚上取样。坩埚的取样位置为合金液面以下10mm处，且保证每个坩埚的取样位置相同。对坩埚样进行镶样、粗磨、细磨、抛光后，采用带有能谱仪的扫描电镜（ZEISS Sigma 300）观察坩埚界面形貌和成分，以及坩埚内壁的成分。采用XRD分析坩埚试样内壁物相变化。

Samples were taken at the center height positions of crucibles of three materials, namely MgO, MGO-Spinel and Al2O3, by using the method of wire electrical discharge cutting. The samples were subjected to sample insertion, coarse grinding, fine grinding and polishing. The microstructure of the samples was observed under a ZEISS Sigma 300 field emission scanning electron microscope, and the EDS of the samples was measured simultaneously. After the vacuum induction smelting experiment is completed, samples are taken from the crucibles of each batch of the experiment. The sampling position of the crucible is 10mm below the alloy liquid surface, and it is necessary to ensure that the sampling position of each crucible is the same. After the crucible samples were embedded, roughly ground, finely ground and polished, the morphology and composition of the crucible interface, as well as the composition of the inner wall of the crucible, were observed using a scanning electron microscope (ZEISS Sigma 300) equipped with an energy spectrometer. The phase changes on the inner wall of the crucible samples were analyzed by XRD.