“…Analysis of the 18 O in-depth diffusion profiles can lead to the determination of the oxygen bulk and grain boundary diffusion coefficients [4,20,[22][23][24]. Secondary Ions Mass Spectroscopy (SIMS) or Secondary Neutral Mass Spectroscopy (SNMS) are, most often, the techniques used to track the isotope distribution in the scale after a two-stage oxidation experiment [18,21,[25][26][27]. As an alternative, Nuclear Reaction Analysis (NRA) is sometimes used: quantitative 18 O deep profiles can be directly obtained from the energy spectrum of the ␣ particles produced by the 18 O(p,␣) 15 N reaction [4,27,28].…”