Diffusion behaviour of hydrogen in nitrogen containing austenitic alloys

Electrochemical permeation technique and thermal desorption spectroscopy we re used to evaluate the hydrogen diffusion, solubility, and trapping behavi our in nitrogen containing austenitic alloys. The hydrogen diffusion of all alloys obeyed Arrhenius relationships in the studied experimental temperat ure range. The apparent diffusion coefficients were determined and the rele vant activation energies were estimated. Nitrogen at higher concentration ( >0.38 wt.%) as well as chromium decrease the hydrogen diffusion whereas nic kel has opposite effect. The thermal analysis of all alloys except Cr18Mn18 N0.57 shows a main single peak at different heating rates indicating no sig nificant hydrogen interaction with microstructural defects. The alloy Cr18M n18N shows a shoulder in addition to the peak which is attributed to nitrog en-hydrogen interaction. The activation energy estimated from the thermal a nalysis is nearly equal to the activation energy for diffusion obtained fro m the Arrhenius plots of the corresponding alloys. (C) 2001 Elsevier Scienc e Ltd. All rights reserved.