Hydrogen permeation barrier – Recognition of defective barrier film from transient permeation rate

摘要: Hydrogen permeation barrier films often exhibit lower efficiency than anticipated. The cause could be defects in the film, high permeability of defect-free (dense) or a combination both. It is very difficult to point at and quantify responsible mechanism since can submicrometer dimensions sparsely populated. This study addresses recognition hydrogen using rate transient evolution analysis. For this purpose mathematical model steady-state through membrane coated either with defective film was developed for diffusion limited regime. Analysis shows that might recognized only experiment. effective coefficient variable depends mainly on ratio coefficients substrate. Contrary this, pinholes has constant value coefficient. Result an experimentally useful criterion when how layer its extent determined.