Authors:Adriana Samide, Bogdan Tutunaru, Aurelian Dobritescu, and Catalin Negrila
the reference to C1 s line, the binding of C–C or C–H located at 285 eV.
In this study, the corrosionproducts obtained on carbon steel surface in 1.0 mol L −1 HCl solution were investigated by
A method of detecting inaccessible metallic corrosion is proposed, in which a gamma-emitting radionuclide added in aqueous solution to the contents of a pipe or vessel attaches itself selectively to corrosion products, and then may be detected from outside using a hand-held gamma detector. This was simulated in the laboratory in preliminary studies. Corrosion products studied were oxidised iron, FeS, goethite, magnetite, spinel and oxidised stainless steel.Kd values were derived for various radionuclides. Of the radionuclides studied,60Co,152Eu,214Pb,214Bi and226Ra seem potentially useful, but not22Na or137Cs.
Investigations of the possible use of Mössbauer measurements for the analysis of the corrosion products of iron are reported.
The Mössbauer spectrum was measured at room and liquid nitrogen temperatures on two samples produced by different corrosion
procedures. The isomeric shift, quadrupole splitting and magnetic splitting observed in the spectra yield information on the
chemical composition. In this way, the chemical forms of the compounds in the samples could be established. The magnetic properties,
revealed by the spectra taken at different temperatures, permitted the identification of the polymorphous modifications. The
rust produced in air saturated with water vapour was found to consist of 50% (w/w) Fe2O3,∼40% γ-FeOOH, and ∼10% β-FeOOH, while the rust produced by periodical immersion in saturated calcium chloride solution is
composed of about equal amounts of β-FeOOH and γ-FeOOH. These findings have been confirmed by the thermoanalytical curves
of the samples. The Mössbauer effect presents a convenient method for the investigation of the corrosion products of iron.
Corrosion products of mild steel exposed to four different cultures of sulfur reducing bacteria (SRB) grown in a synthetic
medium have been studied by transmission Mössbauer spectroscopy (TMS). Cultures of SRB studied are two hydrogenase positive
strains,Desulfovibrio desulfuricans (DD) andDesulfovibrio vulgaris (DV) and two hydrogenase negative strainsDesulfotomaculum orientis orientis (DO) andDesulfotomaculum nigrificans (DN). The corrosion products generated on the coupons as well as in the broth were studied. In all the cases, the corrosion
products removed from coupons showed the presence of green rust 2 (GR2), ferrous sulfides, γ-FeOOH and superparamagnetic (SPM)
α-FeOOH in different proportions. The corrosion products from the broth showed a symmetrical central doublet, which indicates
the presence of γ-FeOOH and SPM α-FeOOH along with ferrous sulfides. The corrosion products from coupons suspended in sewage
water also showed the presence of GR 2 and ferrous sulfides together with oxyhydroxides. FTIR spectrum supports the presence
of these phases in corrosion products. The formation of GR 2 on coupons seems to be the first step for the SRB induced corrosion.
The corrosion rate has been found in the order of DO>DN>DV>DD.
Wellhead equipment corrosion samples including internal surface of choke were analyzed by means of Mössbauer spectroscopy and X-ray diffractometry. The samples include some impurities of quartz, dolomite and calcite. The resulted analysis shows some iron oxides and oxyhydroxides as surface equipment corrosion products.
Long-lived isotopes of corrosion products are very important for the disposal of low-level radioactive wastes. These nuclides serve for risk calculations of accidents. Their determination needs the radiochemical separation from high active main nuclides. Supervision of waste vessels is done by direct non-destructive -spectrometry of the key nuclide60Co for corrosion products. The activity ratios of the long-lived nuclides to the key nuclides are called scaling factors. We have determined such factors radiochemically in evaporation residues of power water and cooling water. They are used for activity calculations of long-lived nuclides in the waste vessels. In case of59Ni the obtained scaling factor was compared with a literature value and values calculated on the basis of nuclear data. Our value was in a good agreement with the calculated one. Due to the fact, that we have used low-level measurement techniques, we could perform the necessary chemical separations in a laboratory not exceeding the 10-fold free-level limit.
Instrumental neutron activation analyses have been carried out on tissues adjacent and distant from metal implants. From the
time-dependence of the concentrations of the corrosion products some conclusions have been drawr on the routes of metal transport
from the implant. Additionally, the behaviour of haematoma iron has been shown as well as the dependence of the zinc concentrations
on different biochemical processes, during implantation and then at the following stages of the development of the metallosis
Authors:J. Narbutt, J. Olza, Z. Przybyłowicz, and S. Siekierski
Extractive purification of boric acid from radioactive corrosion and fission products dissolved in aqueous solutions modelling
nuclear reactor coolants has been studied. Aliphatic 1,3-diols containing 8 and 9 carbon atoms per molecule were used as extractants
fro boric acid. The behaviour of some representative corrosion and fission products as well as various factors affecting their
distribution between the organic and aqueous phases have been investigated under the conditions of boric acid extraction.
Conditions for the effective separation of boric acid from most of the radioactive contaminants are presented.
Authors:M. Saiki, S. Rogero, I. Costa, O. Correa, and O. Higa
Neutron activation analysis has been applied to analyse ear piercing studs manufactured with three different types of metallic materials and also in the analyses of cell culture media in which these studs were immersed. Results obtained in these analyses indicated the release of metal from the studs to the culture media. Zn and Fe were found, respectively, in the extracts of gold coated copper-zinc alloy and stainless steel. These findings were correlated with the results already obtained for studs surface analysis by scanning electron microscopy and for the cytotoxicity tests of culture extracts.
The phase analysis of the rusts generated beneath the primer containing micaceous iron oxide (MIO) and micaceous iron oxide
in combination with red lead (RL), zinc phosphate (ZP), basic lead silicochromate (BLSC) and zinc chromate (ZC) has been carried
out by Mössbauer spectroscopy at room temperature. The rust beneath the coating obtained after immersion of the painted panel
for six months in 3% NaCl, consists mainly of nonstoichiometric magnetite together with small fractions of γ-, α-FeOOH except
in the case of panel painted with RL containing MIO showed only a central doublet indicating the formation of γ-FeOOH and
SPM α-FeOOH. Non-stoichiometry of magnetite as calculated from the ratio of B/A sites of the peaks of magnetite in the spectrum
has been found depending on the nature of anticorrosive pigment present in the primer coating. The order of non-stoichiometry
has been found to be in order of ZC>BLSC>ZP>MIO.