Dependence of parameters of volume self-diffusion in tungsten on the degree of purity in diffusion zone

The noncontact eddy-current method has been used to measure the value delta=Psub(300)/Psub(4.2) on each diffusion specimen, this value being representative of the single crystal purity, where P300 and Psub(4.2) are the resistivities at 300 and 4.2 K, respectively. The mea=0 surements are carried out before application of the diffusion source and after the annealing of specimens with various diffusion sources. The measurement results indicate that the parameters of self-diffusion in tungsten are no more dependent on the concentration of residual impurities only on the level of purity of diffusion zone 4N-5N. Comparison with the parameters measured in the ranges of 1.770 to 2.550 K and 2.660 to 2.230 K is indicative of the linearity of the Arrhenius response of the self-diffusion coefficient in tungsten