Hydrogen transport studies were confined to molecular hydrogen driven permeation through two largely different polycrystalline grain structures: (i) microcrystalline nickel with an average grain size of 3µim and (ii) nanocrystalline nickel with an average grain size of 78 nm. Permeation experiments were conducted in a double chamber ultrahigh vacuum system separated by a test specimen. Hydrogen permeabilities and diffusivities through polycrystalline nickel were measured in the temperature range of 30°C to 200°C. At 30°C the nanocrystalline nickel displayed a six-fold increase in permeability with respect to the microcrystalline nickel. The enhancement in permeability is believed to be the result of enhanced intercrystalline volume fraction in the nanocrystalline nickel.

Array
(
    [1] => Array
        (
            [0] => January
            [1] => Jan
        )

    [2] => Array
        (
            [0] => February
            [1] => Feb
        )

    [3] => Array
        (
            [0] => March
            [1] => Mar
        )

    [4] => Array
        (
            [0] => April
            [1] => Apr
        )

    [5] => Array
        (
            [0] => May
            [1] => May
        )

    [6] => Array
        (
            [0] => June
            [1] => Jun
        )

    [7] => Array
        (
            [0] => July
            [1] => Jul
        )

    [8] => Array
        (
            [0] => August
            [1] => Aug
        )

    [9] => Array
        (
            [0] => September
            [1] => Sep
        )

    [10] => Array
        (
            [0] => October
            [1] => Oct
        )

    [11] => Array
        (
            [0] => November
            [1] => Nov
        )

    [12] => Array
        (
            [0] => December
            [1] => Dec
        )

)