Technical considerations　The story of hydrogen embrittlement

• 水素脆化とは

  • 金属材料に水素が吸収されることで強度が低下する現象

  • 水素イオンが金属結合に侵入しやすいために起こる

  • 腐食や溶接などの過程で水素を取り込むことが原因となる

  • 粒界や応力集中部で割れや破壊が発生しやすくなる

  • ハーバー・ボッシュ法や水素燃料電池などの分野で問題となる

• 水素脆化の研究

  • 古くから行われているが、正体はまだ不明

  • 材料、応力、環境など多くの要因が関係する

  • 水素の量や時間や温度などの拡散に関わるパラメータが重要

  • 水素の挙動を理解することが難しい

  • 軽量化と高強度化の要求に応えるためにメカニズムの解明が必要

• 水素脆化の対策

  • 加熱して水素量を減らす

  • 水素タンク内にアルミコーティングを施す

  • 水素に酸素を添加することで金属疲労を抑制する

  • 水素吸蔵合金や希土類磁石などの製造に水素の粉砕現象を利用する

  • パラジウムに重水素を吸蔵させて常温核融合を試みる

• What is hydrogen embrittlement?

  • A phenomenon in which strength decreases due to the absorption of hydrogen into metal materials.

  • This occurs because hydrogen ions easily enter metal bonds.

  • This is caused by the incorporation of hydrogen during processes such as corrosion and welding.

  • Cracks and fractures are more likely to occur at grain boundaries and stress concentration areas.

  • Problems in fields such as the Haber-Bosch method and hydrogen fuel cells

• Research on hydrogen embrittlement

  • It has been practiced for a long time, but its true identity is still unknown.

  • Many factors come into play, including materials, stress, and the environment.

  • Parameters related to diffusion such as hydrogen amount, time, and temperature are important.

  • Difficult to understand the behavior of hydrogen

  • It is necessary to elucidate the mechanism in order to meet the demands for lighter weight and higher strength.

• Measures against hydrogen embrittlement

  • Heat to reduce hydrogen content

  • Applying aluminum coating inside the hydrogen tank

  • Suppressing metal fatigue by adding oxygen to hydrogen

  • Utilize hydrogen pulverization phenomenon to manufacture hydrogen storage alloys, rare earth magnets, etc.

  • Attempting cold fusion by absorbing deuterium in palladium