Elemental Analysis Of Samples Research Articles

Occurrence and spatial distribution of heavy metals in landfill leachates and impacted freshwater ecosystem: An environmental and human health threat.

Municipal landfill leachates are a source of toxic heavy metals that have been shown to have a detrimental effect on human health and the environment. This study aimed to assess heavy metal contamination in leachates, surface water, and sediments from non-sanitary landfills in Uyo, Nigeria, and to identify potential health and environmental effects of leachate contamination. Over the wet and dry seasons, surface water and sediment samples were collected from an impacted freshwater ecosystem, and leachates samples from six monitoring wells. Elemental analyses of samples were conducted following standard analytical procedures and methods. The results indicated that leachate, surface water, and sediment samples all had elevated levels of heavy metals, implying a significant impact from landfills. Pollution indices such as the potential ecological risk index (PERI), pollution load index (PLI), degree of contamination (Cd), modified degree of contamination (mCd), enrichment factor (EF), geoaccumulation index (Igeo), and Nemerov pollution index (NPI) were used to assess the ecological impacts of landfill leachates. The following values were derived: PERI (29.09), PLI (1.96E-07), Cd (0.13), mCd (0.16), EF (0.97–1.79E-03), Igeo (0), and NPI (0.74). Pollution indicators suggested that the sediment samples were low to moderately polluted by chemical contaminants from the non-sanitary landfills, and may pose negative risks due to bioaccumulation. Human health risks were also assessed using standard risk models. For adults, children, and kids, the incremental lifetime cancer rate (ILCR) values were within the acceptable range of 1.00E-06–1.00E-04. The lifetime carcinogenicity risks associated with oral ingestion exposure to heavy metals were 9.09E-05, 1.21E-05, and 3.60 E-05 for kids, adults, and children, respectively. The mean cumulative risk values for dermal exposures were 3.24E-07, 1.89E-06, and 1.17E-05 for adults, children, and kids, respectively. These findings emphasized the risks of human and biota exposure to contaminants from landfills.

Microstructural and mechanical characterization of the effect of the welding process on creep behavior of welded joint and base metal specimens of Inconel 600

AbstractIn this study, plates of Inconel 600 superalloy were gas metal arc welded to investigate the effects of the welding process on the creep behavior of the welded samples and compare it to the creep behavior of samples in the as-received condition. Creep tests were performed at two temperatures (600 and 650 °C) with different stress levels. During the welding process, three distinctive microstructural zones are generated, i.e. welded material, heat affected zone, and base metal that may affect the properties of the welded joint. Microstructural, elemental analysis of samples was conducted using Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). The experimental results show that creep rupture preferentially occurs in the heat-affected zone of the base metal at 4 mm from the fusion line and that the creep behavior of welded samples is different from that of the base metal. These results can be used in the design of structural components to assure their structural integrity.

Sulfur, Phosphorus and Metals in the Stoichiometric Estimation of Biomethane and Biohydrogen Yields

The estimation of biomethane or biohydrogen yield is used to evaluate energy recovery during the process of the anaerobic treatment of waste and wastewater. Mathematically calculated theoretical values can also be used in biomethane or biohydrogen potential tests as reference points to calculate which fraction of substrate is decomposed, when the substrate degradation stopped and when the sample’s self-digestion begins. This study suggests expanded forms of equations for anaerobic processes leading to either biomethane or biohydrogen. The traditional equations describing the conversion of a substrate with known carbon, hydrogen, oxygen and nitrogen composition were expanded to account for the composition of sulfur (for biohydrogen yields) and phosphorus (both biohydrogen and biomethane yields). As an optional part, one metal cation was also incorporated into the chemical formula of the evaluated wastewater composition in case the compound of biodegradable interest exists as a salt. The equations derived here can be useful for researchers estimating energy recovery based on the elemental analysis of samples, such as algal biomass harvested during harmful algal blooms (HABs). Examples of biomethane and biohydrogen yield estimations from sulfur- and phosphorus-containing compounds are also provided.

Growth of Zn thin films based on electric field by thermal evaporation method and effect of oxidation time on physical properties of ZnO nanorods

Zinc oxide (ZnO) nanorods (NRs) were obtained by oxidation of Zn thin layers, prepared by thermal evaporation method under electric field, at different times of 2.5, 5, 7.5 and 10 h. The crystal structure of samples was investigated using X-ray diffraction (XRD) measurement, which showed samples had a wurtzite hexagonal structure. In addition, field emission scanning electron microscopy (FESEM) indicated that with an increase in the oxidation time, the NRs diameter increased too. Elemental analysis of samples was performed using energy-dispersive X-ray spectroscopy (EDX) which clearly confirmed the presence of Zn and O with an atomic ratio of 1:1. Further, Raman spectra of samples verified wurtzite hexagonal phase due to high- and low-frequency vibration of E2 modes at room temperature and showed that with an increase in the oxidation time, the lattice defects decreased whereas crystal quality of samples increased. Optical properties of samples were determined by UV spectroscopy and demonstrated that when the oxidation time was added, the band gap energy of ZnO NRs decreased, which was attributed to the increase in crystallite size.

Adaptive changes of the elemental status of Kalmyk cattle to conditions of biogeochemical province of the Republic of Sakha (Yakutia)

The purpose of the study was to compare adaptive changes of the elemental status and hematologic indicators of blood of the Kalmyk cattle brought from the Republic of Kalmykia to the Republic of Sakha (Yakutia). Three groups of animals were formed for this purpose: brought cows (n=75), first-generation calves (n=28) and second-generation calves (n=16) received in Yakutia. The body weight of cows during bio-substrate selection made 480.4±13.8 kg. Age – 2.3-8.0 years. Wool samples weighing at least 0.4 g were taken from the top withers of animals. The proximal part of hair 15 mm long from the root was taken for analysis. The elemental analysis of samples was carried out via ICP-AES and ICP-MS. Blood samples were taken from a tail vein. The study was conducted using automatic hematologic analyzer: URIT-2900 Vet Plus (URIT Medial Electronic Co., Ltd, China). It is found that the wool of cows brought to the Republic of Sakha (Yakutia) had smaller concentration of Ca, Na, K, I, Mn, Zn, B, Sr at higher Hg value in comparison with the first-generation cows and smaller Cu and Zn and higher n Cr, Si, Pb content in comparison with the second-generation animals. The study of blood revealed significant changes in their parameters. Thus, the increase of erythrocytes and lymphocytes is observed from one generation to another with the decrease of the average volume of erythrocytes and hemoglobin in a separate erythrocyte.

Assessment of regional differences of chemical concentration in mane hair of the Thoroughbred

The study is conducted on Thoroughbred stallions. The first stage covered the study of the elemental composition (20 elements) of stallion hair (n=148) raised in the southeast of Russia (Stavropol Territory, Krasnodar Krai, Volgograd and Rostov regions). On the basis of obtained results 10, 25, 75, 90 percentile intervals of concentration of the main essential and toxic elements in hair were established. At the second stage, the stallions raised on the farms of Stavropol Territory (n=29) and Krasnodar Krai (n=32), as well as Rostov (n=24) and Volgograd (n=28) regions were examined. Hair samples were selected from mane area in the first cervical vertebra projection. Proximal part of hair (15 mm long) was selected from the hair root for analysis. The elemental analysis of samples was made via inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled mass spectrometry (ICP-MS). It is established that the hair of stallions raised in Stavropol Territory had the highest concentration of Al, As, Sn and Hg at a reliable difference (p≤0.05) with similar indicators for species from Krasnodar Krai. The typical feature of animals raised in Volgograd Region was the maximum concentration of Cd, Pb and Sr fixed against the background of the minimum Cr, I, Mn and Se values. All studied micro-populations were characterized by the excess of established norms of toxic metals. The most considerable deviations (2.5-6.9 times) of aluminum, mercury and tin were typical for animals raised in Stavropol Territory. The species from Krasnodar Krai had lower concentration of zinc. The assessment of the frequency of deviations of the element status from the norm showed that the zinc content in the hair of 48.3% of examined animals from Stavropol Territory and 50.0% of species from Rostov Region made more than 75%. A large number of species from Krasnodar Krai was characterized by the lack of iodine (46.9%) and selenium (34.4%) against the background of the minimum values of cadmium (50.0%) and mercury (100%).

The effect of duration of the productive use on the element status of Holstein cows

The article presents data on the elemental status of highly productive Holstein cows in in terms of duration of productive use. The elemental status was studied on the composition of animal hair. Elemental analysis of samples was carried out by AES-ICP and MS-ICP. It has been established that the first lactation cows differed in minimal concentrations of As, Hg, Cd, Sr wool. With an increase in toxic elements with aging, an increase in zinc levels in the fourth lactation cows was recorded. A significant correlation was found between the sum of toxic elements (As, Hg, Sr, Cd) and concentrations of Cu (r = -0.57), Mn (r = 0.49), Se (r = 0.68) and Zn (r = -0.56) in wool. An assessment of the elemental status of cows in relation to the boundaries of the “physiological norm” revealed an increase in the number of deviations with an increase in the productive use ifrom 2 to 11.

In Vivo Study of Gold-Nanoparticles Using Different Extracts for kidney, liver function and Photocatalytic Application

We report novel gold nanoparticles by green method for different fruit extracts have gaining greater attention due to its versatile properties in different applications. In this article, GNPs synthesis is demonstrated successfully using fresh fruit extract of punica granatum and fragaria. The optical properties, morphology and elemental analysis of samples was done by using) different characterization techniques like SEM EDX and UV-Visible spectroscopy Biocompatibility of GNPs was determined by ALT, AST, ALP, Urea, Creatinine tests and also to investigate the effects of prepared GNPs on the kidney and liver functions. The GNPs prepared by fruit extract of punica granatum have more effects on the rabbits than GNPs prepared from fragaria but this effect normalizes after three days which shows its biocompatibility. To explore the photocatalytic activity of the GNPs the photocatalytic degradation of MB dye is also investigated. The results revealed that GNPs prepared through green synthesis route are found to be efficient enhancement in the degradation of MB dye in visible region due to large surface area. These particles were more active in catalytic reduction due to their high surface energy and in bio-medical applications as biocompatibility.

Countercurrent Chromatography in Elemental Analysis: From Oil to High-Purity Substances

The capabilities of countercurrent chromatography (CCC) in the elemental analysis of samples with different chemical and phase compositions are demonstrated. The combination of the characteristic features of extraction chromatography and multistage extraction with separation and preconcentration processes performed in a closed system (a Teflon coiled column) opens up prospects for applying this method to the analysis of a wide range of materials from high-purity substances to oil and rocks. The use of CCC at the stage of sample preparation makes it possible to decrease the detection limits of impurity elements in high-purity materials to a pg/g level, i.e., by two or three orders of magnitude, as compared with those in the direct determination by inductively coupled plasma mass spectrometry. In the analysis of oil samples, CCC allows one to determine their complete trace element composition (including platinum group, rare, and rare earth elements) due to the concentration of trace elements in a small volume of a stationary aqueous phase retained in the column.

Comparison of active and passive radon survey in cave atmosphere, and estimation of the radon exposed dose equivalents and gamma absorbed dose rates

ABSTRACTRadon (222Rn) measurements were conducted in the Pileki Cave with Radim 3A Active Radon Monitor equipment. Measurements were also done with the passive sampling method with CR-39 nuclear track detectors by exposing them for three months in the cave. Radon concentrations obtained from the active and passive sampling methods showed that, firstly, the concentrations inside the cave measured by the latter method differed greatly due to high humidity levels up to 88%. The total inside radon exposure dose equivalent people were subjected to was estimated to be 19 µSv a−1 for visitors and 24,065 µSv a−1 for guides. The gamma absorbed dose rates were determined for inside and outside the cave. The dose rates were calculated by means of using the 226Ra, 232Th and 40K activity concentrations and by means of real-time measurements. The gamma absorbed dose rates were found to be much higher than the value of 55 nGy h−1 given by UNSCEAR. In addition, the mineralogical compositions and elemental analyses of samples taken from the cave were determined by XRD and WD-XRF methods.

Correlative Microscopy in 3D: Helium Ion Microscopy-Based Photogrammetric Topography Reconstruction Combined with in situ Secondary Ion Mass Spectrometry.

The chemical or elemental analysis of samples with complex surface topography is challenging for secondary ion mass spectrometry (SIMS), if the three-dimensional structure of the sample is not taken into account. Conventional 3D reconstruction of SIMS data assumes a flat surface and uniform sputtering conditions, which is not the case for many analytical applications involving micro- and nanosized particles, composites, or patterned materials. Reliable analysis of such samples requires knowledge of the actual 3D surface structure to correctly reconstruct the SIMS 3D maps. To this end, we introduce the use of photogrammetric 3D topography reconstruction from scanning helium ion microscopy (HIM) correlated with in situ SIMS data for the reconstruction of 3D SIMS data. The HIM and SIMS data are acquired under in situ conditions in a Zeiss ORION NanoFab HIM using a novel SIMS analyzer. We successfully tested the applicability of the approach to generate 3D models of different samples and show that the combination of SIMS and 3D topography is able to provide insights into the influence of the sample topography in a single instrument and with a single ion column and hence without the need for ex-situ sample analysis or additional instrumentation. These findings offer a path toward ion-based correlative 3D spectromicroscopy (3D-HIM-SIMS) and suggest that many combinations of charged particle based P3D (SEM, HIM) and analytical microscopy techniques, such as SIMS, energy-dispersive X-ray spectroscopy (EDX), or ionoluminescence/cathodoluminescence (IL/CL), can be used for correlative microscopy in 3D.

Characterization of Urban Atmospheric PM2.5 by ATR-FTIR, ICP-MS and SEM-EDS Techniques

The study aims to investigate the chemical composition of airborne particulate matter with size below 2.5 �m (PM2.5) collected from Targoviste City area, in the summer of 2015. For this consideration eleven representative points have been chosen for sampling. This research provides interesting data which can clarify the relationship between PM2.5 exposure and the negative effects on human health at urban area level. Three analytical techniques have been developed for the qualitative, quantitative and morphological characterization of PM2.5. The inorganic and organic functional groups of the PM2.5 samples were investigated by Attenuated Total Reflectance - Fourier Transform Infrared Spectrometry (ATR-FTIR). The content of several elements (i.e. Pb, Cd, Cr, Ni, Cu, Mn, Al, Zn and Fe) in samples was determined by Inductively Coupled Plasma - Mass Spectrometry (ICP-MS). The measured concentration of these metals was compared with values reported by the International Agency on urban area in order to establish the minimal element level which cannot be considered as a potential health risk for the urban population. The morphological characterization of PM2.5 was performed by Scanning Electron Microscopy - Energy Dispersive Spectrometry (SEM-EDS). The elemental analysis of samples were performed by EDS and showed that airborne particle was mainly composed of elements, such as C, O, Si, Ca, N and S.

Neural network-random generation approach to analyze X-ray fluorescence spectra

Application of a feed-forward multilayer perceptron neural network to analyze X-ray fluorescence spectra of a compound material is investigated. For this purpose, a general approach is proposed to improve the learning process of the neural network. In this approach, randomly generated composite spectra are constructed from the set of reference spectra corresponding to the pure elements which compose the material. Instead of taking the spectrum as a whole, the input parameters of the neural network arereduced to the neighboring bins of each pure element peak. Bytesting themethodon the spectra of materials made of Ca, Fe, Ni and Cu elements, we obtained an efficiency of about 95% for predicting the relative concentrations of the four elements in the material. Multivariate Data Analysis refers to any statistical technique used to analyze data that arise from more than one variable.Multivariate classification methods based on machine learning techniques have become a fundamental ingredient to most analyses. The multivariate classifiers themselves have signifi- cantly evolved in recent years. Among the multivariate classification methods, Artificial Neural Networks (ANN) are widely used in various fields. Applications range from image analysis to financial movements predictions and analysis. In (1,8) a review of applications of ANN and its potentialities in atomic and nuclear physics is shown. In high energy physic, ANNis mainly used for classification tasks such assignal over background discrimi- nation. With the search for ever smaller signals in ever larger data sets, it has become essential to extract a maximum of the available information from the data (2). ANN are also applied in other cases where strong non-lineal effects are present like in the spectral analyses generated in analytical techniques like PIXE (3) and XRF (X-ray fluorescence) (4). Several types of artificial neural network are commonly used in the practice. Among these types, we can mention the multi layer perceptrons (MLP), the radial basis function networks (RBF) and theself- organizing maps (SOM). They differ by their processing elements and bythe specific manner in which these elements are connected. The potentialities of ANN seem to be more convenient in the repetitive analysis of many spectra presenting similar patterns with specificdifferences. A typical case is presented in the elementalanalysis of samples of unknown composition using energy dispersiveXRF spectroscopy.Their respective spectra

Characterization of heterotrophic and mixotrophic acidophilic bacteria isolated from black shale and acid mine drainage, Khala Chatta, Haripur, Pakistan

Acid mine drainage, Black shale, Mixotrophic, Bacillus. Most of the studies have been carried out in extreme acidic environments focusing on chemolithotrophic action of sulfur and iron oxidizing bacteria such as Acidiphilium and Acidithiobacillus species while little is known about the heterotrophic and mixotrophic acidophilic bacteria in these habitats. The aim of current study was to isolate and characterized glucose oxidizing heterotrophic and mixotrophic bacteria from extreme acidic habitats of black shale and acid mine drainage. The elemental analysis of samples was carried out by using atomic absorption spectrophotometry (AA240FS Fast Sequential Atomic Absorption Spectrophotometer) after acid digestion with aqua regia (3:1 HNO3:HClO4) and heated to 150°C. All the samples were processed on glucose containing bacteriological media and colony-forming unit (CFU) was determined. The isolates were characterized and identified by using standard microbiological techniques. Growth and nutritional conditions of isolated strains have been optimized. A total of ten gram-positive bacteria were isolated, most of them were identified as Bacillus along with Micrococcus and Corynebacterium species. The isolates were acidophilic and acid-tolerant with growth temperature ranges between 25°C to 35°C. Four of the bacteria were mixotrophic in nature because they utilize both organic and inorganic substrates as energy source. Both true heterotrophic and mixotrophic gram positive acidophiles were isolated from low pH environments. The mixotrophs are mostly reported from the environments where the dissolved organic matter is limited such as acid mine drainage.

The structure and chemical layering of Proterozoic stromatolites in the Mojave Desert

AbstractThe Proterozoic carbonate stromatolites of the Pahrump Group from the Crystal Spring formation exhibit interesting layering patterns. In continuous vertical formations, there are sections of chevron-shaped stromatolites alternating with sections of simple horizontal layering. This apparent cycle of stromatolite formation and lack of formation repeats several times over a vertical distance of at least 30 m at the locality investigated. Small representative samples from each layer were taken and analysed using X-ray diffraction (XRD), X-ray fluorescence (XRF), environmental scanning electron microscopy – energy dispersive X-ray spectrometry, and were optically analysed in thin section. Optical and spectroscopic analyses of stromatolite and of non-stromatolite samples were undertaken with the objective of determining the differences between them. Elemental analysis of samples from within each of the four stromatolite layers and the four intervening layers shows that the two types of layers are chemically and mineralogically distinct. In the layers that contain stromatolites the Ca/Si ratio is high; in layers without stromatolites the Ca/Si ratio is low. In the high Si layers, both K and Al are positively correlated with the presence and levels of Si. This, together with XRD analysis, suggested a high K-feldspar (microcline) content in the non-stromatolitic layers. This variation between these two types of rocks could be due to changes in biological growth rates in an otherwise uniform environment or variations in detrital influx and the resultant impact on biology. The current analysis does not allow us to choose between these two alternatives. A Mars rover would have adequate resolution to image these structures and instrumentation capable of conducting a similar elemental analysis.

Effect of rubber particles on cement stabilized gravel system

The primary objective of this paper was to study the mechanical properties and durability of the cement stabilized gravel by different compact method. The influence of rubber particle content on mechanical properties of samples was studied by compaction tests and freezing thawing recycle tests. Pore structure and fractal characteristic of mixture were analyzed quantitatively using mercury intrusion porosimetry (MIP). X-ray diffraction (XRD) was adopted to identify the composition phases. The morphology analysis in micro scale and elemental analysis of samples were carried out by scanning electron microscope (SEM). The optimum compressive strengths of rubber cement stabilized gravel (RCSG) with static compaction method and with vibratory compaction method were obtained by controlling compaction degree and vibration time, respectively. From the compaction tests, the vibratory compaction method is preferred compared with the static compaction method as better compressive strength can be improved by about 340%–360%. Besides, test results also reveal that compressive strength of samples with vibratory compaction method or static compaction method will decrease with the rubber particle bulk content increasing. The freezing thawing recycle tests indicate that freezing thawing resistance has been improved (frozen stability coefficient K has been increased from 0.89 to 0.97) by the addition of rubber particles. MIP tests show that the mean pore diameter and porosity of mixture have been increased from 70 to 250 nm and 9% to 24% respectively, with the rubber particles content increasing. Component analysis shows that the calcium silicate hydrate (CSH) is the predominant hydrate product with or without the addition of rubber particles.

English

This study was conducted to assess the level of heavy metals contamination of soil around oil filling and service stations in the Tamale Metropolis. Soil samples were collected from various oil filling and service stations. Elemental analysis of samples was conducted using atomic absorption spectrometer at Atomic Energy Laboratory, Accra. The metals concentrations ranged from 2.37 to 15.00 mg/kg for Cr; 0.01 to 0.03 mg/kg for Hg; 3.2 to 22.68 mg/kg for Cu; 0.12 to 6.63 mg/kg for Cd and 4.93 to 74.20 mg/kg for Pb. The mathematical models: Index of geoaccumulation (Igeo), enrichment factors (EF), contamination factor and degree of contamination were employed to identify possible levels of pollution from anthropogenic sources. The enrichment factor means places the elements in a decreasing order as Cd > Pb > Cr > Cu > Ni> Fe > Zn > As > Hg > Mn that agreed with others models such as contamination factor, pollution load index and degree of contamination. Elements such as chromium (Cr), copper (Cu), lead (Pb) and manganese (Mg) gave enrichment factor values ranging from 2-5 signifying moderate enrichment. The study revealed that soil contamination by the metals originated from a common anthropogenic source such as the oil filling activities, brake wear, tyres wear and corroded vehicles engine materials since these sources are noted to contribute one or two correlated metals to the natural environment. Hence, pose potential threat to humans and critical environmental media such as water bodies. It is therefore recommended that Environmental Protection Agency (EPA) should regularly monitor the oil filling and service stations to check the levels of heavy metals in the metropolis. Key words: Oil filling, service station soils, enrichment factor, heavy metals, cadmium, Tamale Metropolis.

산화물계 SEN내화물의 슬래그 라인부 침식특성 연구

The corrosion resistance of submerged entry nozzle (SEN) materials were investigated for high-class steel manufacturing. Composite samples were fabricated by mixing ZrO2, Al2O3, MgO, mullite, spinel, and carbon. The raw materials were mixed with attrition milling, compacted in a uniaxial pressure of 200MPa and calcined at 1000 o C for 3 h in N2 atmosphere. The bulk density and apparent porosity of the calcined samples were measured by the liquid displacement method in water using Archimedes's principle. The corrosion resistance of the samples were measured by cup test with mold powder at 1550 o C for 2 h. The microstructure and elemental analysis of samples were observed by scanning electron microscopy (SEM), energy dispersive spectrum (EDS), and X-ray diffraction pattern (XRD). The XRD result shows that the starting raw materials were crystalline phase. The microstructure of fabricated specimen was investigated before and after corrosion tests at 1000 o C and 1550 o C for 2h. ZrO2-C composite showed good resistance in the slag corrosion test. Among the composite oxide materials, ZrO2-Al2O3-C and ZrO2-MgO-C showed better resistance than ZrO2-C in the slag corrosion test. The diameter variation index of ZrO2-C refractory was 16.1 at 1000 o C for 2 h. The diameter variation index of the ZrO2-Al2O3-C refractory was larger than that of the ZrO2-C refractory at 1550 o C for 2 h.

Ni-CeO2 Cermets Synthesis by Solid State Sintering of Ni/CeO2 Multilayer

Nickel and gadolinium doped cerium oxide (GDC) cermet is intensively investigated for an application as an anode material for solid oxide fuel cells based on various electrolytes. The purpose of the present investigation is to analyze morphology, microstructure, and optical properties of deposited and annealed for one hour in the temperatures from 500 ºC to 900 ºC Ni/CeO2 multilayer thin films deposited by sputtering. The crystallographic structure of thin films was investigated by X-ray diffraction. The morphology of the film cross-section was investigated with scanning electron microscope. The elemental analysis of samples was investigated by energy-dispersive X-ray spectroscopy. The fitting of the optical reflectance data was made using Abeles matrix method that is used for the design of interference coatings. The film cross-section of the post-annealed samples consisted of four layers. The first CeO2 layer (on Si) had the same fine columnar structure with no features of Ni intermixing. The part of Ni (middle-layer) after annealing was converted to NiO with grain size exceeding 100 nm. The CeO2 layer deposited on Ni was divided into two layers. Lower layer had small grains not exceeding 25 nm and consisting of NiO and CeO2 mixture. Upper layer consisted of CeO2 columns with approximate thickness of 50 nm. Ni sample annealed at 600 ºC was fully oxidized. The NiO thickness and refraction index were almost steady after annealing in various temperatures. The approximation of experimental reflectance data was successful only for the samples with one transparent homogeneous layer. The reflectance of the Ni/CeO2 samples annealed at intermediate temperatures could not be fitted using one-layer or three-layer model. That may show that a simplified model could not be implemented. The real system has complicated distribution of refraction index. DOI: http://dx.doi.org/10.5755/j01.ms.19.4.3073

Corrosion inhibition of stainless steel type AISI 304 by Mn coating and subsequent annealing with flow of nitrogen at different temperatures

This work reports the enhancement of stainless steel corrosion resistance coated with Mn and post-annealed with flow of nitrogen at different annealing temperatures. Crystallographic variation of the samples by annealing temperature is studied by X-ray diffraction (XRD) while their surface morphology and surface roughness was obtained by means of atomic force microscope (AFM) and scanning electron microscope (SEM) analyses before and after corrosion test respectively. Elemental analysis of samples after corrosion test was investigated by energy dispersive spectroscope (EDS) analysis. The corrosion behaviour of the samples was evaluated by potentiodynamic polarization test in 0.6M NaCl solution. A critical annealing temperature is found at which the highest corrosion resistance can be achieved. Correlation between corrosion resistance, structural and surface morphology results is obtained.