Study on the hydrogen capture behaviour of MnO inclusions

An accurate characterisation of irreversible hydrogen traps in steel is crucial in developing advanced materials that are resistant to hydrogen embrittlement. However, the hydrogen capture behaviour of manganese oxide (MnO) containing inclusions in steels and associated mechanisms are poorly understood. This study provides a systematic evaluation of hydrogen interaction with MnO-containing inclusions. The calculated hydrogen binding energy based on thermal desorption spectroscopy (TDS) is 160.64 kJ·mol⁻¹, where scanning Kelvin probe force microscopy (SKPFM) has established a significantly higher micro-potential for the inclusion body relative to the matrix and the interface following hydrogen charging. The analysis has confirmed that hydrogen is preferentially captured and stored in the MnO-containing inclusions. This study is the first to unambiguously identify MnO-containing inclusions as effective irreversible hydrogen traps, providing an essential theoretical and experimental basis for enhancing the hydrogen resistance of steels by tailoring the inclusion characteristics.