Derivation of hydrogen transport parameters in carbon fibre composites by modelling transient release in isovolumetric desorption experiments

Abstract

A non-stationary model has been developed to determine the hydrogen diffusivity ( D) and Sieverts' constant ( K s) in carbon fibres composites (CFC), from isovolumetric desorption experiments using short loading times. For homogeneous materials such as nickel the model predictions and the experimental results are in good agreement. Assuming the CFC as homogeneous specimen, apparent values of D and K s for two types of CFC (NB11 and N11(SEP)) were obtained. The model was successfully refined in order to account for CFC non-homogeneity. The determinant role of the fibre on the total K s of hydrogen in CFC and the role of the porosity on the hydrogen D and K s in matrix is explicitly illustrated. The model capabilities suggest its use as a tool for the design of CFC from the point of view of their hydrogen transport properties.