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1.
The k0-based internal mono standard instrumental neutron activation analysis (INAA) method was used for the composition analysis of some irregular shape stainless steel (SS) samples of type SS 316M, which is used as fuel cladding in Indian fast breeder test reactor (FBTR). The method utilizes in situ relative detection efficiency using γ-rays of the activation products present in the sample for overcoming γ-ray self-attenuation. Samples were neutron activated using the thermal column as well as the core position of the reactor and the assay of radioactivity was carried out by high-resolution gamma ray spectrometry. The elements determined were Fe, Cr, Ni, Mo, Mn, Co, Cu, As and W. Since all the major elements (Fe, Cr, Ni, Mo and Mn) were amenable to NAA, the relative elemental concentrations with respect to Fe, obtained by this method, were converted to their absolute values by mass balance. The results were compared with specified compositions and found to be satisfactory. In order to validate these results obtained by the standard-less approach, sub samples of SS 316M in solution forms were analyzed by prevalent relative and k0 methods of INAA, and results were found to be in good agreement. The accuracy of the internal mono standard INAA method has been evaluated by analyzing an alloy steel certified reference material, CRM 225/1 of British Chemical Standards (BCS).  相似文献   

2.
This article describes synthesis of the difference carboxylic acid derivatives of triphenylene and its complexation properties with Fe/Cr (III)-salophen. For this purpose, the carboxylic acid derivatives of 2,3,6,7,10,11-hexahydroxytriphenylene were synthesized and then reacted with four new Fe(III) and Cr(III) complexes involving tetradenta Schiff bases bis(salicylidene)-o-phenylenediamine-(salophenH2). The prepared compounds were characterized by means of elemental analysis carrying out infrared spectroscopy (IR), thermogravimetric analysis (TG), nuclear magnetic resonance (1H NMR), elemental analysis and magnetic susceptibility measurement. The complexes can also be characterized as low-spin distorted octahedral Fe(III) and Cr (III) bridged by carboxylic acids.  相似文献   

3.
The study of an arc discharge in argon has been made with the cathode of the discharge system in the form of molten chromite, FeO·Cr2O3. The partial pressure distributions of the elements Fe and Cr, as well as the temperature distributions, have been determined in the arc by spectroscopic methods. The data obtained were used, in conjunction with a mathematical model, for the determination of the oxygen species distribution in the same medium. The cathode bath surface was measured by means of the two-wavelength method. From a consideration of free energy of reaction values, it is concluded that the presence of elemental Fe and Cr in the cathode bath is mainly related to the migration of Fe+ and Cr+, present in the arc, toward the liquid cathode. The formation of these elements in the molten cathode is very unlikely.  相似文献   

4.
Equilibrium of Cr atoms between the surface layer and bulk of a binary alloy was analyzed. The Gibbs adsorption equation was used to obtain the dependence of the adsorption activity of atoms in the surface layer on their activity in the bulk. An approximate thermodynamic method was used to calculate the adsorption of Fe (Ni) and Cr atoms in the surface layers of Fe-Cr and Ni-Cr alloys. According to calculations, there was negative adsorption, X Cr ≪ 1, in the surface layer of the alloys caused by a large difference between the Gibbs surface energies of Cr and Fe (or Ni). The negative adsorption of Cr shifted chemical reaction equilibria on the alloy-oxide film boundary both in oxidation in air and in anodic passivation, 3FeO (NiO) + 2Cr = Cr2O3 + 3Fe(Ni), toward oxide film enrichment in the FeO (or NiO) oxide. A unified method for calculating the composition of oxide films on alloys was used for both processes. The method was based on the use of the initial data on the Gibbs surface energy of metals constituting alloys. The calculated oxide film compositions were close to the experimental X-ray photoelectron spectroscopy data.  相似文献   

5.
Three methods were developed for the analysis of the alloying elements chromium and nickel in Zircaloy-2 and Zircaloy-4, alloys of zirconium used extensively in the nuclear industry as nuclear fuel sheathing. Zircaloy was dissolved in hydrofluoric acid followed by oxidation of Cr(III) to Cr(VI) by perchloric acid. The polarographic peak of CrO 4 2– in alkaline medium was used to determine Cr. Nickel was determined, after HF dissolution, using the polarographic peak of the nickel-ammonia complex, Ni (NH3) 6 2+ . In an alternative method for Ni, the sample was dissolved in HF and the polarographic peak of the nickel-fluoride complex, NiF 4 2– , was used. Careful control of fluoride ion concentration and the pH eliminated the harmful effect of fluoride on the capillary behaviour of the dropping mercury electrode. The detection limits for chromium, nickel-ammonia and nickel-fluoride in Zircaloys were 0.0016, 0.0033, and 0.0041%, respectively.  相似文献   

6.
Laser-induced breakdown spectroscopy was used to determine the elemental composition of a CeO2 composite powder for process control verification during lanthanide borosilicate glass fabrication. Cerium oxide is used as a surrogate for plutonium oxide, which along with other canister contents will be combined with frit to make glass. Laser-induced breakdown spectroscopy data for the composition of the CeO2 batch containing concentrations of Ce, Cr, Si, Fe, Ta, Ni, Zn, Al Mg, Gd, and W were quantitatively determined from laser-induced breakdown spectroscopy spectra of both pellet and powder samples. The results of both forms were compared and it was determined that the pellet data gave slightly better precision than the powder sample.  相似文献   

7.
因高温、辐射等极端环境限制,核领域亟需具备在线快速检测特性的分析仪器。基于小型风冷脉冲激光器与小型光纤光谱仪实现了远程激光诱导击穿光谱技术(LIBS)装置的小型化,对该便携式远程LIBS系统的定量分析性能进行了研究,实现了5 m外样品的元素遥测。在单脉冲激光能量100 mJ,脉冲延时1.0 μs的分析条件下,实现了白水晶、陶瓷及铝合金样品中Mn、Si、Al、Na、Ba、Ca及Cr元素的激发,验证了LIBS技术对材料组分和物料成分的远程探测能力,对铝合金样品的定量分析结果显示,该远程遥测系统对铝合金样品定量测量结果的最大相对平均偏差为12%,具备执行核领域快速分析场景下的半定量检测能力。  相似文献   

8.
The sulfidation behavior of Fe20Cr and Fe20Cr0.7Y alloys in H2–H2S atmospheres at 700 and 800°C was determined by thermogravimetry. Isothermal measurements were carried out and the sulfidation kinetics were evaluated from the mass gain vs. time curves. The reaction products were examined in a scanning electron microscope and the compositions of micro-regions were determined using energy dispersive spectroscopy and X-ray diffraction. Yttrium addition increased the sulfidation resistance of the FeCr alloy. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

9.
In the present study, we discussed to synthesis of a new Schiff base with nitro groups and its complexation properties with Fe/Cr(III) salen/salophen capped complexes. For this, 1,3,5-tris (formylphenoxymethyl)benzene (1, TRIPOD) involving aldehyde groups was converted to the Schiff base derivative (2, TNPIM-TRIPOD) using 4-nitroaniline. The synthesized compound 2 were reacted with four new trinuclear Fe(III) and Cr(III) complexes involving tetradenta Schiff bases N,N-bis(salicylidene)ethylenediamine-(salenH2) or bis(salicylidene)-o-phenylenediamine-(salophenH2). Characterization of all compounds was made with elemental analysis, infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), nuclear magnetic resonance (1H-NMR), and magnetic susceptibility measurement. The complexes can also be characterized as low-spin distorted octahedral Fe(III) and Cr(III) bridged by nitro groups.  相似文献   

10.
The determination of 93Zr concentration, a long-lived radionuclide present in spent nuclear fuel and in the structural components of nuclear reactors, is a major issue for nuclear waste disposal purpose and to validate neutronic calculation codes. To measure 93Zr concentration in irradiated cladding material with a high precision, an analytical method based on the use of multiple collector-inductively coupled plasma mass spectrometer (MC-ICPMS) combined to isotope dilution technique was developed. First a radiochemical separation of zirconium from a zircaloy sample (a zirconium alloy used as a cladding material for nuclear fuel elements), has allowed to obtain a very pure zirconium fraction with no potential isobaric interferences for mass spectrometric measurements. Then as the determination of all zirconium isotope ratios in the sample is necessary for the isotope dilution method, a MC-ICPMS procedure was developed to perform these precise measurements. Finally, the determination of 93Zr concentration in the same sample was performed, after preparation and calibration of a 96Zr spike solution. The uncertainties obtained on isotope ratios of zirconium by MC-ICPMS were in the order of 0.1%. The final uncertainty obtained on the 93Zr concentration in the nuclear material used and after chemical purification was lower than 0.6%.  相似文献   

11.
2,4,6‐tris(4‐hydroxybenzimino)‐1,3,5‐triazine [ 1 , 2 ] ( III ) have been synthesized by the reaction of 1 equiv melamine and three equiv 4‐hydroxybenzaldehyde, and characterized by means of elemental analysis, 1H‐NMR (nuclear magnetic resonance spectroscopy), Fourier transform infrared (FTIR) spectrscopy, liquid chromatography‐mass spectroscopy (LC‐MS). L ( IV ) has been synthesized by the reaction of one equiv ( III ) and three equiv 4‐(thiophenoxy)phenyloxylohydroxymoyl chloride ( II ) , and characterized by means of the same methods. Then, four novel trinuclear Fe(III) and Cr(III) complexes involving tetradentate Schiff bases N,N′‐bis(salicylidene)ethylenediamine‐(salenH2) or bis(salicylidene)‐o‐phenylenediamine‐(salophen H2) with L (IV) have been synthesized and characterized by means of elemental analysis, FTIR spectrscopy, LC‐MS, thermal analyses. The metal ratios of the prepared complexes have been determined using AAS. The aim of the present study is synthesis of novel tridirectional‐trinuclear systems and to present their effects on magnetic behavior of [salenFe(III)], [salophenFe(III)], [salenCr(III)], and [salophenCr(III)] capped complexes. The complexes have also been characterized as low‐spin distorted octahedral Fe(III) and Cr(III) bridged by keton‐oxime group. J. Heterocyclic Chem., (2011).  相似文献   

12.
This article describes synthesis of novel Schiff base and its complexation properties with Fe(III) and Cr(III). Firstly 1,3,5-tris (formylphenoxymethyl)benzene (1, TRIPOD) with tris aldehyde groups were synthesized using the 1,3,5-trisbromomethylbenzene and 4-hydroxybezaldehyde. The compound 1 was converted to the Schiff base derivative (2, TCPIM-TRIPOD) with p-aminobenzoic acid. The prepared TCPIM-TRIPOD were reacted with four new trinuclear Fe(III) and Cr(III) complexes involving tetradenta Schiff bases N,N-bis(salicylidene)ethylenediamine-(salenH2) or bis(salicylidene)-o-phenylenediamine-(salophenH2) and characterized by means of elemental analysis carrying out infrared spectroscopy (IR), thermogravimetric analysis (TG), nuclear magnetic resonance (1H-NMR), elemental analysis and magnetic susceptibility measurement. The complexes can also be characterized as low-spin distorted octahedral Fe(III) and Cr(III) bridged by carboxylic acids. The tricarboxylic acids play a role as bridges for weak antiferromagnetic intramolecular exchange.  相似文献   

13.
The k0-based internal monostandard instrumental neutron activation analysis (IM-INAA) method was applied for quantification of trace impurities in seven high purity aluminum samples used as fuel cladding in a research reactor. Samples along with BCS CRM 182 (Si–Al alloy) were irradiated in high flux reactor neutrons for 10–15 h. In situ detection efficiency, needed in concentration calculation ratio by IM-INAA, was obtained using gamma rays of activation products produced in the samples. Elemental concentration ratios obtained with respect to Fe (used as internal monostandard) were converted to absolute concentrations by determining concentration of Fe by relative method of NAA. Concentrations of ten trace elements (Sc, Cr, Co, Zn, Ga, La, Ce, Sm, W and Hf) including major element Fe were determined in this work. The method used is non-destructive in nature and does not need multielement standards. Results of IM-INAA were compared with those obtained by relative method of INAA and inductively coupled plasma atomic emission spectrometry (ICP-AES). Details of methodologies and results obtained by all methods are discussed and compared in the paper.  相似文献   

14.
In the present work, high temperature oxidation of HP40 alloy was carried out at 1050 °C under H2–H2O and air atmospheres; the influence of atmosphere on surface morphology and composition was studied. Octahedral crystals with considerable spalled regions are present on the surface of alloy oxidized under air, the oxide scale composes of MnCr2O4, Cr2O3 and (Fe, Ni)Cr2O4 and spalled regions exhibit base alloy and SiO2‐rich regions. The surface of alloy oxidized under H2–H2O is fully covered by small granular crystals and blade‐type structures without spallation, and the oxide scale composes of MnCr2O4 and Cr2O3. Moreover, X‐ray photoelectron spectroscopy analysis shows considerable difference in chemical valence states of Mn, Cr and O elements on both alloy surfaces, and hydroxyl compounds exist on the alloy oxidized under H2–H2O atmosphere. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

15.
In Terra Nova Bay region (northern Victoria Land, Antarctica), the interactions among soil, meltwater and lakes are poorly understood with regard to the physicochemical transformations that occur when solid materials are exchanged among them. In order to ascertain the natural dynamics of several elements, namely Al, As, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Ti and Zn, as well as the perturbations by human activities and/or global contamination, soils and sediments from four catchments (Tarn Flat, Edmonson Point, Inexpressible Island and Northern Foothills) were studied.To accomplish the above mentioned objectives, the particle-size distribution and mineralogical composition, as well as the total C, H and N contents and the total concentrations of the investigated elements were determined. Finally in order to assess metal mobility, the modified BCR three-step sequential extraction procedure was applied to the samples and the partitioning of five metals, namely Cr, Fe, Mn, Pb and Zn, into different fractions was determined.Lithology and topography are the main factors that differentiate the physicochemical characteristics of the soils and sediments investigated. The lacustrine sediments and the soils sampled around the lakes showed a similar mineralogical and chemical composition, as evidence that rock- and soil-weathering processes occur primarily during the warm summer periods, when the lakes are partially ice-free. Nevertheless the presence of chlorite in these systems indicated that chemical weathering has taken place even in these extreme conditions. In general, the geochemical composition of soils and sediments in this Antarctic area seems to be influenced mainly by the nature of the bedrock and by the input of sea-spray, and, to a lesser degree, by mechanical and chemical weathering as well as by biological processes; no evidence of a local or global anthropogenic contamination was found.  相似文献   

16.
Secondary phase precipitates of a Zircaloy sample have been characterised by X-ray microspectroscopy. In Zircaloy-2 X-ray microscopy reveals pictures with a 40 nm resolution identifying Fe, Cr and to a lower occurrence Ni phases up to size of the micrometer. Analysis by X-ray spectroscopy defines the structure of specific secondary phase precipitates. The feasibility tests demonstrate that the characterisation of Fe and Cr can be performed on 100 nm size phases allowing the analysis of the Fe or Cr atoms environment in these secondary phase precipitates.  相似文献   

17.
Summary The alloys Fe17.8Cr, Fe16Cr2.4Mo and Fe18Cr14Ni2.5Mo (at%) were polarized in 0.5 mol/l H2SO4 or in 0.1 mol/l HC1 + 0.4 mol/l NaCl. The composition of the oxide layer and of the metallic layer beneath the oxide and the kinetics of the passive layer formation were determined by AES and XPS. In the active region, selective dissolution of Fe leads to an enrichment of Cr, Ni and Mo at the metal/electrolyte interface. In the passive region, the thickness of the rapidly formed passive layer is determined by the potential. The chromium content of the passive layer approaches a stationary, high value. The passive layer essentially consists of the anions O2- and OH and of the cations of Cr, Fe, Mo, whereas Ni — and less pronounced Mo — are enriched below the layer.  相似文献   

18.
A series of novel the semicarbazone derivatives of calix[4]arene have been synthesized and then immobilized onto amino functionalized magnetic nanoparticles. Magnetic Fe3O4 nanoparticles were prepared by the chemical co-precipitation of Fe(III) and Fe(II) ions and the nanoparticles were modified directly by 3-aminopropyltriethoxy silane (APTES) to introduce reactive amine groups onto the particles’ surface. The characterization of the prepared compounds was made by FT-IR, elemental analysis, TGA/DTG and NMR techniques. The sorption properties of the new calix[4]arene based magnetic sorbents toward Cr(VI) ion were also studied. The results showed that the prepared magnetic nanoparticles were effective sorbents for the removal of Cr(VI) ion. Also, Langmuir and Freundlich isotherm models were applied for Cr(VI) ion sorption by using MN-C2 and it was found that the experimental data confirmed to Langmiur isotherm model.  相似文献   

19.
Researcher’s interest is increasing worldwide to study the role of trace elements in brain tissues. This paper discusses the application of k 0-instrumental neutron activation analysis to study the distribution of trace elements in seven different anatomical regions of goat brain. These regions include cerebellum, cerebrum, medulla oblongata, meninges, midbrain, pons and thalamus. The analysis protocol followed 1 h irradiation at 10 MW material testing type nuclear research reactor with nominal thermal neutron flux of 2 × 1013 cm?2 s?1. A total of 14 elements, namely Br, Co, Cr, Eu, Fe, Hg, K, Na, Rb, Sb, Sc, Se, Tb and Zn were determined in all parts. Reliability of the method was assessed by analyzing biological reference material IAEA-336 (lichen). On comparing the analytical results with the healthy human brain data, it showed that eight elements (Eu, K, Na, Rb, Sb, Sc, Se, Tb) were found with relatively higher elemental concentrations in human brain. Principal component analysis revealed distribution of seven parts in different three groups having similar elemental concentrations of elements.  相似文献   

20.
2,4,6-Tris(4-hydroxybenzimino)-1,3,5-triazine (II) has been synthesized by the reaction of 1 equiv. melamine (I) and 3 equiv. 4-hydroxybenzaldehyde and characterized by means of elemental analysis, 1H NMR, Fourier transform–infrared spectroscopy, and liquid chromatography–mass spectrometry (LC-MS). 2,4,6-tris(4-(2-phenyl-2-keto-hydroxyiminoyloxy)benzimino)-1,3,5-triazine L (III) has been synthesized by the reaction of 1 equiv. II and 3 equiv. chloroisonitrozoacetophenone and characterized by means of the same methods. Four novel trinuclear Fe(III) and Cr(III) complexes involving tetradentate Schiff bases N,N′-bis(salicylidene)ethylenediamine-(salenH2) or bis(salicylidene)-o-phenylenediamine-(salophen H2) with L (III) have been synthesized and characterized by means of elemental analysis, Fourier transform–infrared spectroscopy, LC-MS (ESI+), and thermal analyses. The metal ratios of the prepared complexes have been determined using atomic absorption spectroscopy. The aim of the present study is to synthesize novel tridirectional-trinuclear systems and to present their effects on magnetic behavior of [salen or salophenFe(III)/Cr(III)] capped complexes. The complexes have also been characterized as low-spin distorted octahedral Fe(III) and as distorted octahedral Cr(III) bridged by keton-oxime group.  相似文献   

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