Mass-Spectroscopic Study of the Diffusion and Solubility of Helium in Submicrocrystalline Palladium

摘要

By the method of helium thermal desorption from submicrocrystalline palladium presaturated in the gaseous phase, the diffusion coefficient D_(eff) and solubility coefficient C_(eff) of helium are measured in the range P = 0-3 MPa and T = 293-508 K. The pressure dependence of C_(eff) fattens at high pressures. At low saturation pressures, the temperature dependence of the diffusion and solubility coefficients may be divided into (1) high-temperature (400-508 K) and (2) low-temperature (293-400 K) ranges described by the exponentials D_(1,2) = D_0exp(-E_(1,2)~D/kT) and C_(1,2) = C_0exp(-E_(1,2)~S/kT). The energies of diffusion activation are E_2~D = 0.0036 0.0015 eV and E_1~D = 0.33 ± 0.03 eV and the solution energies are E_2~S = -0.025 ± 0.008 eV and E_1~S = 0.086 ± 0.008 eV in the low- and high-temperature ranges, respectively. mechanisms behind the diffusion and solution of helium are discussed.