Search results for "CORROSION"
showing 10 items of 456 documents
Investigation of corrosion defects in titanium by positron annihilation
2015
Abstract The positron annihilation method was used to study the formation of defects in titanium samples during their corrosion in the vapor of a 3% HCl solution. In particular, the distribution of defects depending on the distance from the corroding surface and the impact of an external magnetic field on the concentration of vacancies forming during the corrosion of titanium layers close to the surface were determined.
Preliminary corrosion studies of P-91 in flowing lead–lithium with and without magnetic field for Indian lead–lithium ceramic breeder test blanket mo…
2014
To study the corrosion of P-91 (9% chromium and 1% molybdenum) material with lead–lithium (Pb–Li) eutectic, two experiments were carried out in a forced convection loop, at eutectic temperature of 550 °C. The first experiment was carried out at a velocity of 15 cm s−1 for 1000 h and the second experiment, at a velocity of 30 cm s−1 for 2700 h. In both the experiments, P-91 sample coupons were exposed to Pb–Li flow in the presence and absence of magnetic field. Samples were analyzed using an optical microscope, scanning electron microscope (SEM) and electron probe micro-analyzer (EPMA). Micro-Vickers hardness testing was also carried out. Dissolution of elements into liquid metal is the main…
Corrosion processes and their inhibition as studied by Mössbauer conversion and other electron spectroscopies
1989
To study corrosion processes of iron and steel and measures of their inhibition, a detailed knowledge of the phase composition and of phase transformations in very thin layers close to the attacked surface of the material is necessary. The information depths of integral (ICEMS) and depth selective (DCEMS) conversion electron Mossbauer spectroscopy are well suited for such investigations, but some effort is necessary if technical samples, i.e. nonenriched in57Fe, are to be studied. In many cases of practical importance, full information on the corroded surfaces cannot be got from Mossbauer spectra only, and a combination with Auger and photoelectron spectroscopies, in-including scanning and …
Positron Annihilation in Corroded Steels St20 and St3S
2006
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.
The Influence of a Magnetic Field on the Formation of Corrosion Defects in Selected Metals and Steels, Analysed Using Positron Annihilation Method
2014
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.
Effect of magnetic field on the corrosion of iron and St20 steel as studied by positron annihilation [Phys. Status Solidi B 247(7), 1822-1828 (2010)]
2011
We alert our readers that part of the contents of the article by R. Pietrzak and R. Szatanik, Phys. Status Solidi B 247, 1822 (2010) [DOI 10.1002/pssb.200945124] was already published in an earlier conference proceedings paper by the same authors which appeared in Nukleonika 55, 31 (2010).
Effect of Composition on the Photoelectrochemical Behavior of Anodic Oxides on Binary Aluminum Alloys
2006
The photoelectrochemical behavior of anodic films on Al alloys, containing titanium, tantalum, and tungsten (valve metals), has been studied as a function of alloy composition and anodizing conditions. Photocurrent spectroscopy has been used to get information on bandgap and the flatband potential values of different mixed oxides. Both insulator-like and semiconducting behavior has been observed for anodic oxides grown on Al-W and Al-Ti alloys dependent on alloy initial composition. Optical bandgap values, E opt g , of different oxides are in accordance with predictions based on the correlation between E opt g and the difference of electronegativities of the oxide constituents, indicating p…
Recent advances in using Photocurrent Spectroscopy for the Characterization of Passive Films on Metals and Metallic Alloys
2020
La Spettroscopia a Fotocorrente (PCS) viene qui presentata come tecnica d’indagine non distruttiva, utile per lo studio delle proprietà elettroniche di film passivi accresciuti su metalli e leghe metalliche. In questo lavoro sono stati studiati tramite PCS film passivi di acciai inossidabili quali AISI 304L, AISI 316L e Duplex 2507, accresciuti in soluzione 0.25 M di NaOH a 82°C, condizione simulante l’ambiente aggressivo tipico di operazioni di pulizia nell’industria del food and beverage. Il band gap dei film passivi cambia notevolmente dopo l’immersione per gli acciai 304L e 316L, con un arricchimento in Fe dei film passivi durante il trattamento. Per l’acciaio Duplex invece, il film pas…
Chloride role in the surface of nickel electrode
1998
The chloride ion participation in the dissolution process on nickel electrodes in acid media as well as in the formation of the passive layer and in the pitting corrosion induction were studied. Composite electrodes containing nickel powder dispersed in a polymeric matrix show similar processes to those observed in polycrystalline nickel. Furthermore, phenformine hydrochloride inhibits the dissolution process due to the adsorption of the organic cation on the metal surface, although it does not protect the metal from pitting corrosion. Electrochemical impedance spectroscopy data allowed us to propose a physical model for the role of chloride ion in the dissolution and passivation processes …
Sprouting and intussusceptive angiogenesis in postpneumonectomy lung growth: mechanisms of alveolar neovascularization
2013
In most rodents and some other mammals, the removal of one lung results in compensatory growth associated with dramatic angiogenesis and complete restoration of lung capacity. One pivotal mechanism in neoalveolarization is neovascularization, because without angiogenesis new alveoli can not be formed. The aim of this study is to image and analyze three-dimensionally the different patterns of neovascularization seen following pneumonectomy in mice on a sub-micron-scale. C57/BL6 mice underwent a left-sided pneumonectomy. Lungs were harvested at various timepoints after pneumonectomy. Volume analysis by microCT revealed a striking increase of 143 percent in the cardiac lobe 14 days after pneum…