Permeability experiments were used to study hydrogen diffusion and trapping in dual phase (DP), quenched and partitioned (Q&P), advanced high strength steels. The measured reversible hydrogen trap densities indicated that (i) trapping was less significant at a more negative potential, and (ii) the lattice diffusion coefficient of hydrogen could be measured from the partial transients at the most negative potentials. The densities of reversible hydrogen traps evaluated from complete decays from −1.700\ua0V were\ua0∼\ua02\ua0×\ua010 sites cm, and were a factor of two higher than those from partial decay transients between −1.700\ua0V and −1.100\ua0V
