Accession Number : AD0254474


Title :   THE DETERMINATION OF THE COVERAGE ON NICKEL AND STEEL DURING ELECTROLYTIC HYDROGEN EVOLUTION


Corporate Author : PENNSYLVANIA UNIV PHILADELPHIA JOHN HARRISON LAB OF CHEMISTRY


Personal Author(s) : BOCKRIS, J O'M ; DEVANATHAN, M A V


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/254474.pdf


Report Date : 28 Feb 1961


Pagination or Media Count : 58


Abstract : The galvanostatic double charging method was applied to determine the coverage of Ni cathodes with adsorbed atomic H in 2 N NaOH solutions. Anodic current densities were varied from 0.05 to 1.8 amp/sq cm. The plateau indicating absence of readsorption was between 0.6 and 1.8 amp/sq cm, for a constant cathodic c.d. of 1/10,000 amp/sq cm. The variation of the adsorbed H over cathodic c.d.'s ranging from 10 to the -6th power to 1/10 at a constant anodic c.d. of 1 amp/sq cm were calculated and the coverage calculated. The mechanism of the H evolution reaction was elucidated. The rate determining step is discharge from a water molecules followed by rapid Tafel recombination. The rate constants for these processes and the rate constant for the ionisation, calculated with the extrapolated value of coverage for the reversible H electrode, were determined. A modification of the Tafel equation which takes into account both coverage and ionisation is in harmony with the results. A new method for the determination of coverage suitable for corrodible metals is described which involves the measurement of the rate of permeation of H by electrochemical techniques which enhances the sensitivity of the method.


Descriptors :   *ADSORPTION , *STEEL , *CATHODES , *NICKEL , *ELECTROLYSIS , ELECTROCHEMISTRY , HYDROGEN , DEPOSITS , DIFFUSION , HYDROGEN EMBRITTLEMENT , DETERMINATION , ELECTROLYTIC CELLS , ELECTRODEPOSITION


Subject Categories : Metallurgy and Metallography


Distribution Statement : APPROVED FOR PUBLIC RELEASE