Investigation of diffusion and electromigration of hydrogen in palladium and PdAg alloy

Abstract Diffusion and electromigration of hydrogen in PdH 0.1 , Pd 77 Ag 23 H 0.1 and Pd 50 Ag 50 H 0.1 alloy were measured by means of resistivity method. It is known that hydrogen migrates towards the cathode within the temperature range of 300–473 K in the PdH 0.1 and Pd 77 Ag 23 H 0.1 system. In Pd 50 Ag 50 H 0.1 , hydrogen migrates towards the cathode below 400 K, but towards the anode at higher temperatures. Its effective valency increases together with temperature. At the same time it satisfies the linear dependence on inverse specific resistance ρ : Z eff = Z i +( k / ρ ). The constants Z i and k have the following values: (1.05±0.01) and −(3.81±0.04)×10 −8 Ω m for hydrogen in PdH …

The Influence of Magnetic Field on Annihilation of Positrons in Corroded Steel St-20

The influence of mechanical damaging on the lifetime of positrons In ultrahigh-molecular polyethylene

We study the influence of damaging of ultrahigh-molecular polyethylene [(PE-UHMW) Chirulen®1120] applied, among other materials, in the production of hip endoprostheses on the spectra of positrons lifetime in this material. Polyethylene samples were damaged by the impacts, rolling friction, and collisions with metal balls in a planetary mill. The changes in the parameters of the spectra of positrons lifetime related to the annihilation of orthopositronium (o-Ps) were analyzed depending on the mechanical energy transferred to the sample. On the basis of the Eldrup–Tao model, the changes in the radii of voids in which positroniums are formed and annihilated and the changes in the degree of fi…

Positron Annihilation in Medical Substances of Insulin

Positrons lifetimes were measured in medical substances of insulin (human and animal), differing as far as the degree of purity and time of their activity in the organism are concerned. In all of the cases the spectrum of positron lifetime was distributed into three components, with the long-life component ranging from 1.8 to 2.08 ns and the intensity taking on values from 18 to 24%. Making use of Tao–Eldrup model, the average radius of the free volume, in which o-Ps annihilated, and the degree of filling in the volume were determined. It was found that the value of the long-life component for human insulin is higher than that of animal insulin. Moreover, the value of this component clearly…

Positron Annihilation in Corroded Steels St20 and St3S

The paper deals with examining the lifetimes of positrons emitted from Na source in corroded St20 and St3S steels. Influence of the method of defecting the sample surfaces on the spectrum of positron lifetimes was investigated. Influence of temperature of initial annealing of samples, plastic deformation, electrolytic hydrogenation and corrosion in HCl vapors on trapping positrons in the examined steels was also determined.

Investigations into the Influence of Hydrogen and Defects on the Spectra of Lifetime of Positrons in Palladium

The Influence of Filtration of Atrasine on the Spectrum of Positron Lifetimes in Immobilized Liquid Filtration Membranes

The spectra of positron lifetimes were investigated in elements which were later used to form an immobilized liquid membrane and also in the immobilized liquid membrane, after different times of atrasine filtration. Next, the spectra of positron lifetimes were separated out into three components. The values of the components of the positron lifetimes spectrum indicated the formation of the Ps-atom both in the elements composing the membrane and in the very membrane itself. An influence of the filtration time of atrasine on the values of all components of positron lifetimes spectrum was found. On the basis of Eldrup–Tao model, changes in the sizes of spherical free spaces in the membrane and…

The influence of external uniaxial stretching on the electromigration and diffusion of hydrogen in iron

Electromigration and diffusion of hydrogen in iron, depending on unit elongation, were investigated. The resistivity method was applied in the investigations. It was found that the obtained experimental results cannot be described by means of a single flux of hydrogen, which diffuses in the electric field. In order to explain the obtained results, we assumed the existence of the following two fluxes of hydrogen in the stretched metal: migration, according to the interstitial mechanism, and migration according to the interstitial-defective mechanism. The dependence of effective valences and diffusion coefficients for both mechanisms were determined.

Measurements of Positrons Lifetimes in Corroded Nickel

It is over twenty years now that the nuclear method of conducting investigations into defects in the volume and on the surface of solids, based on positron annihilation phenomenon, has been developing on a quite intensive scale [1-3]. The present work is an attempt at adopting positron annihilation to investigations of the phenomenon of pitting corrosion in metals. Pitting occurs mainly in environments containing chlorides and affects metals and alloys covered with passivating oxide layers. Research carried out for many years by the use of various methods . has proved that pittings, which could — after some time — take sizes as large as the tenth of the millimeter order, are formed in the p…

Spectra of Positrons Lifetimes in Choose Gel Drugs

antiphlogistic drugs were investigated. The basic components in them were sodium salts of diclophenac and they difiered from one another with the chemical composition of other components. It was found that in all of the investigated spectra there occurred a component which testifled to the formation of positronium. The difierences in the values of ortho-Ps component lifetimes and their intensity can be attributed to the presence of ingredients modifying the efiects of the drug.

The Influence of a Magnetic Field on the Formation of Corrosion Defects in Selected Metals and Steels, Analysed Using Positron Annihilation Method

The method of positron lifetime measurement was used to analyse the in uence of a magnetic eld on the kinetics of corrosion defect formation in near-surface layers of iron, titanium as well as S20 and S0H18N9 steel grades. The listed metals, which belong to ferroand paramagnetic materials, have di erent sensitivity to corrosion. It was found that not only the presence of a magnetic eld, but also its direction in uence the dimensions and the concentration of defects formed during corrosion.