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Dependencies of the relative elongation ε under the constantly applied stress at T = 1.8 K on the endurance time t of polycrystalline parahydrogen (p-H2, ∼ 0.2% of o-H2) of high purity (99.9999 mol.%), with varying deuterium content, were measured. The region of linear dependence between the measured creep rates ε ˙ of samples and the applied stress σ was revealed. The conclusion that the low-temperature creep of the studied p-H2 possesses a vacancy-type diffusion character was made on the basis of linear dependence ε ˙ ∼ σ. Determination of the low-temperature self-diffusion coefficient of vacancies D in solid p-H2, which characterizes the rate of low-temperature mass transfer, was performed. The cases of migration of vacancies in the crystal bulk, along boundaries separating individual crystallites, as well as between dislocations existing in crystals, are considered. A significant decrease in the ε ˙ and D values with an increase in the isotope concentration in the samples was observed, while maintaining the linear relationship between ε ˙ and σ for the studied p-H2. [ABSTRACT FROM AUTHOR]

Impedance spectroscopy, chronovoltammetry, chronopotentiometry, scanning electron microscopy, and atomic-force microscopy were used to examine the corrosion behavior in acid and alkaline media and the morphology of nickel coatings electrodeposited from acetate, tartrate, and isobutyrate electrolytes at a temperature of 20-25°C. Models describing the nickel corrosion processes in H2SO4 and NaOH solutions were suggested. It was found that nickel coatings formed from isobutyrate electrolytes have the highest corrosion resistance. [ABSTRACT FROM AUTHOR]

The relative elongation f. of samples of high purity (99.9999 mol. % with respect to nonhydrogenic impurities) parahydrogen (p-H2, ~0.2% o-H2) with different amounts of the stable hydrogen isotope deuterium is measured as a function of applied stress σ at temperatures of 1.8-4.2 K. The samples were subjected to uniaxial tension by stepwise loading. The ratio [D]/[H] of the number [D] of deuterium atoms to the number [H] of p-H2 hydrogen atoms ranged from 0.0055 ± 0.0005 at. % up to 0.07 at. %. For deuterium enriched p-H2, the easy slip dislocation stage vanished from the σ(ε) curves and there was a significant reduction in the total relative elongation of the samples, as well as a substantial increase in the hardening coefficient dσ/dε. Deformation of samples of p-H with deuterium contents higher than the natural amount produces an unusual change in their shape owing to the appearance of a rotational component of the low-temperature plastic mass transfer. [ABSTRACT FROM AUTHOR]