マイクロプリント法による鋼中水素の可視化技術に及ぼすゼラチン硬膜処理の影響

抄録

Hydrogen microprint technique is a simple and powerful method to visualize hydrogen behavior in metallic materials by using redox reaction between hydrogen and silver bromide. Polished surface of specimens is covered with nuclear emulsion, and silver particles left on the surface after fixing represent sites of hydrogen emission. If silver particles are unstable during fixing and leave original sites of the reaction with hydrogen, hydrogen behavior can not be accurately analyzed. For the purpose of optimizing the experimental procedure to study hydrogen behavior in steels properly, effects of gelatin hardening on the stability of silver particles were examined in the present study by changing type of photographic fixer and pre-fixing treatment. Fixing specimens with hardening fixer was effective to prevent silver particles from moving to other locations during fixing. Applying hardening fixer, however, made it difficult to observe silver particles that existed in a thick gelatin layer. The optimum procedure was fixing specimens with non-hardening fixer after gelatin hardening by formalin. With this procedure, silver particles were stable during fixing and there was no difficulty in observing silver particles that represented points of hydrogen emission.