During the preparation of metallographic samples, sawing, cutting, grinding, polishing and other processes are required. After the blank samples to be observed are cut out from the castings, the observation surfaces of the samples are first polished with abrasive paper with particle sizes of 100, 200, 800, 1000 and 2000. After the grinding accuracy is reached, the samples are polished with W35 polishing paste Light. Finally, wash the surface with clean water, spray alcohol and blow dry. Figure 1 shows the metallographic photos prepared by the above process.
In this experiment, the equipment used for scanning tissue analysis is jsm-7900 scanning electron microscope provided by national standard (Beijing) inspection and Certification Co., Ltd. The samples to be tested are the metallographic samples treated with Keller solution for 15 s. Figure 2 shows an example of a scanned photograph.