Preparation methods for scanning electron microscope characterization of nano-carbides in cold work steel X153CrMoV12

The suitability of different preparation methods for imaging nano-carbides by scanning electron microscopy (SEM) was evaluated taking the example of cold work steel X153CrMoV12 manufactured by powder metallurgy. The ion beam slope cutting method, carbide etching using sulfurous acid, and electrolytic polishing using the Struers electrolyte A2 were considered in this study. The preparation aim was to develop an appropriate method for the qualitative detection of nano-carbides using the SEM to characterize relatively large sample areas and to substitute time-consuming transmission electron microscope examinations. The carbide detection was performed on heat-treated samples using sulfurous acid, applying the ion beam slope cutting method, and by electrolytic polishing using the electrolyte A2. In the SEM, nano-carbides could be observed on the sample surfaces prepared by ion beam slope cutting and the electrolytically polished ones. The examinations were performed on conventionally quenched and tempered material samples of cold work steel X153CrMoV12 (reference condition) as well as on samples subjected to deep cryogenic treatment (DCT). Deep cryogenic treated samples showed a significantly increased number of nano-carbides.