62 TDS Evaluation of the Hydrogen Trapping Capacity of NbC Precipitates Available to Purchase

In this work, ferritic steel containing NbC precipitates was investigated. The materials were subjected to various heat treatments, giving rise to different precipitate size distributions as determined by TEM (Transmission Electron Microscopy). The steels were hydrogen charged both electrochemically and from a gaseous phase, followed by multiple TDS (Thermal Desorption Spectroscopy) measurements. Electrochemical charging gives rise to a low temperature peak (80–120°C), originating from the hydrogen trapped near grain boundaries and at NbC precipitates, having activation energy ranging between 24 and 44 kJ/mol. Gaseous charging leads to a high temperature TDS peak (450–550°C), which indicates that hydrogen is trapped by incoherent NbC precipitates, with activation energy ranging between 62 and 71 kJ/mol.