Semi-quantitative Chemical Analysis Research Articles

Occurrence, distribution, and composition of black sand along the Red Sea, Egypt

Black sand along the Red Sea is often composed of volcanic minerals and heavy minerals. The Red Sea region is known for its unique geological features, and black sand beaches can be found in various areas along its shores. The study presents a comprehensive semi-quantitative chemical analysis of black sand samples collected from various locations along the red sea, revealing significant variations in their elemental compositions. The main oxides were identified in each sample, determined through X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses, indicate diverse mineralogical compositions. The spatial distribution of minerals at each site is depicted through mapping. Additionally, Fourier-transform infrared (FTIR) spectra offer information on the functional groups present in the samples, revealing the existence of hydroxyl groups, aliphatic compounds, and adsorbed water molecules. For Qusier-Elsharm Alqbly, Safaga, Marsa Alam, Gabal Alrosass, Hurghada Titanic, Hurghada Elahiaa, Gemsa, and Ras Elbehar samples, the results highlight the presence of various minerals, such as Quartz, Calcite, Titanium Dioxide, Magnetite, Hematite, Aluminum Oxide, Zirconium Dioxide, Chromium (III) Oxide, and others, providing insights into the geological characteristics of each location. The differences in mineral content among the examined sites are linked to the geological and mineralogical makeup of the source rocks upstream and midstream in the basins that discharge into the surveyed regions. So, variations in black sand concentrations among different locations offer insights into the geological and mineralogical diversity of the studied areas along the Red Sea coast. This study addresses the existing knowledge gap by focusing on the preliminary exploration and description of the occurrence, distribution, and composition of black sand along the Red Sea in Egypt. whereas the results provide valuable insights into the geological diversity of black sand deposits in the surveyed areas, underscoring the need for additional research and interpretation of these variations. Therefore, the in-depth examination of mineralogical composition and crystal structures establishes a foundation for future investigations in the field of geology and earth sciences.

Aging temperature effect on the phase composition, microstructure, and selected mechanical properties of non-equiatomic TiZrNbTaMo/Mn HEAs targeted for biomedical implants

High entropy alloys (HEAs) have been developed for many applications and recognized for their superior strength, ductility, and corrosion resistance, attracting the attention for biomedical applications. This study aims to evaluate the effect of aging treatment at distinct temperatures on the phase composition, microstructure, and selected mechanical properties of non-equiatomic TiZrNbTaMo and TiZrMoNbTaMn HEAs for potential use as biomedical implants. The TiZrNbTaMn sample exhibited a single BCC phase, while the TiZrNbTaMo a major BCC and minor HCP phases. The microstructure of the TiZrNbTaMo sample was composed of BCC grains with some acicular precipitations of the HCP phase in the grain boundaries, having the aging temperature acted in the grain growth and secondary phase precipitation. Contrarily, the TiZrNbTaMn sample exhibited larger BCC grains permeated with a minor amount of acicular structures, which were entirely decomposed with the aging treatments. The semi-quantitative chemical analysis indicated that the phase composition was a result of elemental chemical segregation, having the refractory metals (Mo, Ta, and Nb) preferentially located in the inner region of the grains, while the other ones (Ti, Zr, and Mn) in the grain boundary. The aging treatment acted in the phase precipitation/dissolution oppositely on the samples through the atomic diffusion mechanism induced by the temperature. The elastic modulus and Vickers microhardness were sensitive to the chemical and phase composition of the samples, having the TiZrNbTaMo aged at 773 K achieved better performance than the commercial Ti-6Al-4 V alloy for use as biomedical implants.

Application of the Rietveld Method to Quantify Mineral Phases in a Kaolin Mineral

The applications of the mineral kaolin are varied, such as the ceramic industry, and the pharmaceutical industry, among others; although it is generally found in mining deposits accompanied by other mineral species considered contaminants. The above makes it necessary to apply qualitative and quantitative analysis techniques that determine the purity of the mineral, from its extraction, during its mechanical processing and kaolin recovery. In this work, a procedure for quantification of the majority species in the Kaolin mineral is proposed, according to the procedure proposed by Rietveld, from the diffractogram obtained by the x-ray diffraction technique, as well as the knowledge of the crystallographic characteristics of the mineral constituents. Three models are proposed based on the structural parameters of the phases present in the system: tridymite, cristobalite, and kaolinite. The experimental results show the total adjustment of the diffraction pattern in which it is observed that the weight percentage corresponds to 40.0% for tridymite, 39.5% for cristobalite, and 20.5% for kaolinite. These results were corroborated by specific semi-quantitative chemical analyses using scanning electron microscopy.

Passive of CRFS Technology in Soil-Cement Application

In Brazil, with the ban on the production, sale, and use of chrysotile asbestos, the sector’s industry opted to replace asbestos with CRFS Technology—Cement Reinforced with Synthetic Wire (fiber cement); that is, another product to be disposed of in landfills. This work aimed to determine a composite based on clay, fiber cement powder, and cement that meets the technical specifications of Brazilian soil–cement application standards to contribute to a more sustainable treatment of the future disposal of fiber cement products. With the characterization analysis of the materials, we identified that the clay granulometry is heterogeneous and distributed from 0.1 µm to 25 µm. In comparison, 75% of the fiber cement powder has grains greater than 10 µm. For clay, the liquidity limit is 39.67%, the plasticity limit is 25.01%, and the plasticity index is 14.66%. In the semiquantitative chemical analysis, silicon oxide (SiO2) and calcium oxide (CaO) stood out as the main oxides found, reflected in the mineralogy as quartz and calcium silicate. Therefore, we identified the percentage of organic matter in clay at 2%, using the result of the thermogravimetric analysis. The results described met the normative parameters foreseen for soil–cement applications. That said, the technological characterization was carried out by tests of linear retraction, water absorption, and simple mechanical compression on the specimens made under an axial pressure of 31.2 Mpa in the formulations defined in this work. The formulations with 10% cement and 20% and 30% fiber cement powder are suitable for use in soil–cement bricks, as they have volumetric shrinkage percentages from 2% to 2.5%, water absorption ranging from 18.66% to 19.39%, and simple compressions from 4.25 Mpa to 6.88 Mpa, meeting the requirements of Brazilian standards for soil–cement applications. It is concluded that the results showed that it is possible to produce soil–cement bricks with passive fiber cement products converted into powder, avoiding improper disposal and unwanted environmental impacts.

Effects of Partial Manganese Substitution by Cobalt on the Physical Properties of Pr0.7Sr0.3Mn(1-x)CoxO3 (0 ≤ x ≤ 0.15) Manganites.

We have investigated the structural, magnetic, and electrical transport properties of Pr0.7 Sr0.3 Mn(1-x)Cox O3 nanopowders (x = 0, 0.05, 0.10 and 0.15). The Pechini Sol-gel method was used to synthesize these nanopowders. X-ray diffraction at room temperature shows that all the nano powders have an orthorhombic structure of Pnma space group crystallography. The average crystallite size of samples x = 0, 0.05, 0.10, and 0.15 are 33.78 nm, 29 nm, 33.61 nm, and 24.27 nm, respectively. Semi-quantitative chemical analysis by energy dispersive spectroscopy (EDS) confirms the expected stoichiometry of the sample. Magnetic measurements indicate that all samples show a ferromagnetic (FM) to paramagnetic (PM) transition with increasing temperature. The Curie temperature TC gradually decreases (300 K, 270 K, 250 K, and 235 K for x = 0, 0.05, 0.10, and 0.15, respectively) with increasing Co concentrations. The M-H curves for all compounds reveal the PM behavior at 300 K, while the FM behavior characterizes the magnetic hysteresis at low temperature (5 K). The electrical resistivity measurements show that all compounds exhibit metallic behavior at low temperature (T < Tρ) well fitted by the relation ρ = ρ0 + ρ2T2 + ρ4.5T4.5 and semiconductor behavior above Tρ (T > Tρ), for which the electronic transport can be explained by the variable range hopping model and the adiabatic small polaron hopping model. All samples have significant magnetoresistance (MR) values, even at room temperature. This presented research provides an innovative and practical approach to develop materials in several technological areas, such as ultra-high density magnetic recording and magneto resistive sensors.

Influence of Milling and Use of Ni and Al Containing Metal Binder in NbC-Based Cermets

This study presents the development of niobium carbide cermets bound to nickel and Ni-12Al (wt%). The use of Ni-12Al (wt%) and Ni aims to replace strategic elements such as cobalt (Co) utilized in tungsten carbide-based cermets. Cermets of different compositions were processed by conventional powder metallurgy. Microstructural analysis with semi-quantitative chemical analysis by EDX, Vickers microhardness and density measurement were performed to evaluate the influence of high energy milling application and sintering temperature on the properties of these cermets. A milling time of 20 min in a planetary mill and sintering temperatures of 1420 ºC or 1450 ºC resulted in homogeneous microstructures, densities close to 90% and hardness of around 1000 HV1, showing a potential for use of this material in cutting tools.

Retgersite from mine dump of the Lill shaft, Březové Hory ore district, Příbram (Czech Republic)

Rare sulphate of nickel, retgersite, was identified on the one specimen collected on the dump of the Lill shaft, Březové Hory ore district, Příbram (Czech Republic) in 1990s. The specimen consists of quartz gangue with dominant millerite and sphalerite. Retgersite forms light blue to blue-green curved fibrous microcrystalline aggregates up to 2 mm in size with vitreous lustre, growing on the surface and in small outer vugs of the supergene altered gangue. Retgersite was identified by PXRD and its refined unit-cell parameters (for the tetragonal space group P41212) are: a 6.7838(2) Å, c 18.2951(8) Å and V 841.94(4) Å3. Results of semiquantitative chemical analysis (EDS) as well as vibrational spectra (Raman, infrared) including their tentative assignments are also given. The studied retgersite was formed by (sub)recent weathering of primary nickel mineralisation (mostly millerite) in the mine dump conditions.

Türkiye Piyasasında Satılan Bazı Talk Pudralarının Mineralojik ve Yarı Nicel Kimyasal Bileşimi

40 of the talcum powders sold in Turkey were investigated to determine whether they contain dangerous minerals such as chrysotile and tremolite for human health. Mineralogical and semi-quantitative chemical analyzes of the powders were made. Besides talc, mostly calcite, kaolinite, magnesite, smectite/chlorite, dolomite, quartz and rarely chrysotile (?) and tremolite were determined in the powders. It was determined that the calcite content was close to talc in some samples. Talc, tremolite and chrysotile crystals are partly flat and partly pointed and splintered. In addition, acicular, twisted, filamentous morphology crystals were also determined. Stack appearance is also observed in the fibers, sometimes in rod, tubular, and plate-like shapes. The size of the rod-like crystals is larger than those given in the literature for chrysotile (≥5µm). In the semi-quantitative chemical composition analysis, in addition to Si and Mg in the structure of silicate minerals, Fe, Ca and Al contents in many crystals were also determined. The same ratio was determined as the Mg:Si=3:2 ratio in the structural formula of chrysotile in rod-like/filamentous morphology. In general, the Si content is much higher than that of Mg, while in a few analyzes the content of these elements has been found to be close to equal. Fe or Al content has also been determined in some crystals and the Fe content should be taken into account. Because Fe, asbestos minerals may cause the risk of cancer formation in the tissues in the biological system. In addition, micron-sized quartz may carry the risk of silicosis.

Mechanical and Wetting Properties of Ta2O5 and ZnO Coatings on Alloy Substrate of Cardiovascular Stents Manufactured by Casting and DMLS.

In the last years, additive manufacturing technologies have been developed, especially direct metal laser sintering, and used in the dental and medical implant domains. Cardiovascular stents have evolved from bioinert, bare metal cages to biomimetic devices that promote tissue regeneration or healing. In this paper, comparisons concerning mechanical properties between Co–Cr alloy and cast 304L stainless steel were realized using FEM analysis, necessary for manufacturing cardiovascular stents by DMLS technology using Co–Cr alloy. The purpose of this paper consists of the evaluation of the contact angle at the interface of the Co–Cr alloy manufactured by DMLS, respectively, cast stainless steel 304L, and thin film deposition realized by the e-gun method (Ta2O5 and ZnO). Scanning electronic microscopy SEM and EDX techniques were employed for morphological investigation of the sintered samples manufactured by the DMLS process. They were also used for semi-quantitative and qualitative chemical and metallographic analyses. The e-gun coating was used to obtain thin films with the nanometer order of Ta2O5 and ZnO with a protective role to improve the corrosion resistance, roughness, and antiseptic role.

Supergénna mineralizácia na II. horizonte Východnej šachty hnedouhoľnej bane Handlová (Slovenská republika)

At the II. horizon of the Eastern shaft of Handlová coal mine the occurrence of mineral assemblage of secondary minerals was identified. These accumulations consist of sulphate group minerals confirmed by PXRD and semiquantitative chemical analysis (EDS), namely gypsum, alunogen, pickeringite, melanterite, sideronatrite and epsomite. Sulphates form coatings, crystalline crusts and aggregates, which crystallized on the walls of mine corridors. The dimensions of these accumulations are reaching approximately 1.5 x 1.3 m with thickness up to 5 cm. The refined unit-cell parameters of alunogen (for the triclinic space group P-1) are: a 7.413(1), b 26.944(4), c 6.051(1) Å, α 90.05(1), β 97.65(1), γ 91.82(1)°, V 1197.1(3) Å3, pickeringite (for the monoclinic space group P21/c): a 6.1808(8), b 24.252(2), c 21.220(2) Å, β 100.36(1)°, V 3128.8(6) Å3 and melanterite (for the monoclinic space group P21/c): a 14.022(5), b 6.503(2), c 10.945(4) Å, β 105.83(3)°, V 960.2(7) Å3. Sideronatrite and epsomite were identified in mixture with the most significant diffraction maxima for sideronatrite: 10.252/100, 4.905/37, 3.424/10, 3.067/9 and epsomite: 5.347/18, 5.302/18, 4.489/26, 4.215/100, 4.201/59, 2.880/24, 2.747/23, 2.677/18. Accumulations of minerals were formed on the mine walls. Secondary sulphates are considered as products of the weathering of Fe-rich carbonates, pyrite and other sulphidic minerals which are part of associated pelosiderites embedded in the clays and claystones. Locally, gypsum and hexahydrite were also identified in the form of transparent crystals and white powdery aggregates on the calcite speleothems genetically linked to Mesozoic limestones and gypsum-rich Lower Triassic Werfen Formation. Unit-cell parameters refined from X-ray powder diffraction data are for hexahydrite (for the monoclinic space group C2/c): a 10.107(1), b 7.2114(8), c 24.424(3) Å, β 98.28(1)°, V 1761.7(3) Å3.

Integrating the MasSpec Pen with Sub-Atmospheric Pressure Chemical Ionization for Rapid Chemical Analysis and Forensic Applications.

Analytical methods that allow rapid, sensitive, and specific chemical measurements are central to forensic analysis and essential to accelerating compound screening and confirmation. We have previously reported the development of the MasSpec Pen technology as an easy-to-use and disposable hand-held device integrated to a mass spectrometer for direct analysis and molecular profiling of biological samples. In this Technical Note, we describe a new apparatus that integrates the MasSpec Pen device with a subatmospheric pressure chemical ionization (sub-APCI) source and an ion trap mass spectrometer for detection and semiquantitative analysis of forensic-related compounds. Coupling the MasSpec Pen device to a sub-APCI source allowed semiquantitative analysis of the drugs cocaine and oxycodone, the agrochemicals atrazine and azoxystrobin, and the explosives trinitrotoluene and dinitroglycerin in under 20 s. Using chemical ionization, improved reproducibility and sensitivity for targeted chemical detection and compound identification was achieved while maintaining the user-friendly features of the hand-held MasSpec Pen device. Limits of detection in the high picogram to low nanogram range were obtained for the compounds analyzed, which are within the range of federal screening cutoffs and those reported for other ambient ionization MS techniques. Altogether, the MasSpec Pen sub-APCI system described enabled rapid and semiquantitative chemical analysis for forensic applications and could be further adapted and applied to other areas of chemical testing.

Application of X-ray photoelectron spectroscopy to study interfaces for solid-state lithium ion battery

&lt;sec&gt;Solid-state lithium-ion batteries have attracted much attention due to their high safety, high energy densities and other advantages. However, solid-state lithium-ion batteries cannot realize large-scale commercial use. There are key scientific and technical issues that have not been resolved, especially interface issues, such as high resistance and instability of the interface. The X-ray photoelectron spectroscopy (XPS), as an important surface analysis method, can perform qualitative and semi-quantitative chemical analysis of the interface, which makes XPS can be widely used to study the solid-state lithium-ion battery interfaces. In this paper, we review the recent research progress of solid-state lithium-ion battery interfaces by using XPS, and summarize and review the XPS experimental principle, experimental method, experimental results and their effects on interface performance. The XPS analysis methods for solid-state lithium-ion batteries include &lt;i&gt;ex-situ&lt;/i&gt; XPS, &lt;i&gt;in-situ&lt;/i&gt; XPS reflecting the real-time changes of the battery interface, and operando XPS based on the actual working conditions of the battery. &lt;/sec&gt;&lt;sec&gt;The &lt;i&gt;ex-situ &lt;/i&gt;XPS can study oxide solid electrolyte interfaces, sulfide solid electrolyte interfaces and artificial solid electrolyte interface (SEI) layers to access information about the chemical composition of the interface, predict the performance of the interface, obtain the chemical distribution in space, and evaluate the chemical structure and irregularity of the interface. With ultraviolet photoemission spectroscopy (UPS) the interface work function, energy band bending and energy structure of the full battery can be obtained. &lt;i&gt;In-situ&lt;/i&gt; XPS can effectively study the process of chemical reactions between the electrolyte and the electrode. The key prerequisite is the controllable &lt;i&gt;in-situ&lt;/i&gt; construction of the electrolyte/electrode interface. &lt;i&gt;In-situ&lt;/i&gt; XPS research can directly study the electrochemical changes of the interface. &lt;i&gt;In-situ&lt;/i&gt; XPS/UPS can study the energy level alignment of solid-state lithium-ion batteries, indicating that a space charge layer is formed at the solid electrolyte interface, and the energy band bending occurs. The degree of energy band bending is reflected in the binding energy shifts of the related elements at the interface. The change of the energy structure in the deposition process can be determined by the binding energy shifts of the related elements at the interface and the change of the interface work function. Operando XPS performs XPS characterization at the same time under the working condition of the battery. Operando XPS can be combined with electrochemical characterization to observe the effects of interface reaction and solid electrolyte decomposition products on electrochemical performance, thereby determining the main components that affect electrochemical performance. It can also be combined with the &lt;i&gt;ex-situ&lt;/i&gt; XPS to study the interface reaction mechanism and influencing factors. The information obtained includes the chemical states of elements after the interface reaction has occurred, the evolution of interface elements in the process of real-time interface reaction, the energy structure change and interface component overpotential, thus having a better understanding of interface composition, interfacial structure change, kinetics of interface reaction, and interfacial ion migration of the solid-state lithium ion batteries.&lt;/sec&gt;

Quasi-spectral characterization of intracellular regions in bright-field light microscopy images

Investigation of cell structure is hardly imaginable without bright-field microscopy. Numerous modifications such as depth-wise scanning or videoenhancement make this method being state-of-the-art. This raises a question what maximal information can be extracted from ordinary (but well acquired) bright-field images in a model-free way. Here we introduce a method of a physically correct extraction of features for each pixel when these features resemble a transparency spectrum. The method is compatible with existent ordinary bright-field microscopes and requires mathematically sophisticated data processing. Unsupervised clustering of the spectra yields reasonable semantic segmentation of unstained living cells without any a priori information about their structures. Despite the lack of reference data (to prove strictly that the proposed feature vectors coincide with transparency), we believe that this method is the right approach to an intracellular (semi)quantitative and qualitative chemical analysis.

Data on phase and chemical compositions of black sands from "El Ostional" beach situated in Mompiche, Ecuador.

Data revealing the phase and chemical compositions of natural black sands from “El Ostional” beach, located in the northern Ecuadorian Pacific coast have been presented. The samples were collected from six points over the shore area of approximately 500 × 40 m2. The data on crystalline phases (iron titanium oxide, orthoclase feldspar and zircon) were determined by X-ray powder diffraction (XRPD), while semi-quantitative chemical analyses of major (Fe and Ti) and trace elements were obtained by X-ray fluorescence spectroscopy (XRF). The phase composition was verified by scanning electron microscopy (SEM), using backscattered electron (BSE) mode and energy dispersive spectroscopy (EDS). These comprehensive data are a contribution to valorize ilmenite-hematite solid solutions from natural resources towards the identification of novel technological applications.

A noninvasive complementary study of an Egyptian polychrome cartonnage pigments using SEM, EPMA, and Raman spectroscopy

Raman spectroscopy, optical microscopy, scanning electron microscopy (SEM), and electron probe microanalysis (EPMA) were used to study pigments on an Egyptian cartonnage from the Ptolemaic period (305–30 bc). The surface morphology of each color region was examined using backscattering (BS) and secondary electron imaging. SEM X‐ray energy dispersive spectrometry and EPMA wavelength dispersive spectroscopy provided semiquantitative chemical analysis of each pigment. Raman spectroscopy was used to identify the minerals associated with the pigments. This technique confirmed the presence of cinnabar (α‐HgS) in the red part of the fragments. A mixture of orpiment (As2S3) and bonazziite (β‐As4S4) and/or alacránite (As8S9) was detected in the yellow regions of the fragments. The orange pigment was confirmed to be a mixture of orpiment, uzonite (χ‐As4S5), and pararealgar (As4S4). Egyptian blue (CaCuSi4O10) and Egyptian green ((Cu,Ca)SiO3) pigments were detected from blue/green dark‐colored regions of the fragments.

Characterization and geological context of the silex used as raw material for archaeological artifacts in the Taió region - Santa Catarina, southern Brazil

The town of Taio is home to archaeological sites, including the INDUMA SC-TA-19 site studied by the Anchieta Research Institute, which cataloged various lithic artifacts made from silex (flint). According to the different authors, silex is a rocky material with controversial formation processes in the literature. In this context, this work aimed to characterize these silex artifacts, define their source area and geological origin, based on field studies, optical petrography, scanning electron microscopy, and semi-quantitative chemical analysis. The methodology employed allowed characterizing its source area, defining that silex consists of bioclasts, wrapped in silica polymorphs, combined with fibrous chalcedony, in different proportions and establishing its formation in a marine environment.

Incidencia del uso de gasolina extra y mezcla al 5 % con etanol anhidro en los microfiltros de los inyectores multipunto

El objetivo de este estudio fue analizar los depósitos en inyectores con una mezcla de combustible de 87 octanos con porcentajes de etanol anhidro al 5 % y gasolina de 87 octanos. La fase experimental se llevó a cabo en dos vehículos con motor de encendido a una altura de prueba de 2810 m.s.n.m. al recorrer, cada uno, una distancia de 3 000 km dentro del Distrito Metropolitano de Quito. Se aplicaron dos métodos: Estereoscopía o Visión para el análisis de los microfiltros de los inyectores; y el análisis químico semicuantitativo Microscopía Electrónica de Barrido para las muestras de los residuos originados en los filtros. En el caso de la estereoscopia, en ambos vehículos, se produjo una reducción de la obstrucción de los filtros cuando se usa gasolina con etanol anhidro al 5 %. La microscopía electrónica de barrido permitió concluir que hay una mayor presencia del elemento azufre con un 4 % en los residuos cuando se usa gasolina con un 5 % de etanol, a diferencia del 1 % en los residuos cuando se aplica gasolina de 87 octanos.

On the properties of hot forged Ti-6Al-4V alloy aimed for surgical implants

The investigation here is aimed to examine the structural and mechanical changes that might have occurred during the hot forging process, a process to obtain a surgical hip implant, and the subsequent heat treatment. Microstructural characterization, morphological and semi-quantitative chemical analyses have been accomplished using an optical and scanning electron microscope. Chemical analyses of all surfaces obtained by the dotted method in all analyzed samples have shown the approximate equal content of aluminum, titanium, vanadium, iron, and silicon. Tensile testing and measurements were following obtained microstructure, showing the uniformity of microstructure and properties along the forging part, as well as over its cross section. All tests proved that hot forging could be a suitable procedure for surgical implants processing.

Preparation, structural and spectroscopical properties of silver terbium diphosphate AgTbP2O7

Abstract Silver terbium diphosphate AgTbP2O7 was prepared by solid state reaction at T=500° and characterized by combining SEM-EDS morphological investigation and semi-quantitative chemical analysis via Scanning Electron Microscopy (SEM) equipped with energy dispersive X-Ray spectroscopy (EDS), structure solution via Rietveld refinement of powder X-ray diffraction (PXRD) data, and Fourier transform infrared (FTIR) spectroscopy. The synthesized compound is monoclinic, P21/n space group, with cell parameters: a=11.9108(3) Å, b=6.90265(16) Å, c=6.62030(15) Å, β=90.3702(5)° and V=544.28(2) Å3. The crystal structure consists of a network of zig-zag chains of TbO8 polyhedra extending along the b axis, bridged by P2O7 diphosphate groups and by chains of AgO7 polyhedra running along the c crystallographic direction. MIR (medium infrared) spectrum shows bands typical of P–O modes of diphosphate compounds. Observed band multiplicity is in agreement with the symmetry reduction with respect to orthorhombic rare earth diphosphates with similar stoichiometries reported in the literature.

Micro-Structural Characterization and Semi Quantitative Chemical Analysis of Ferrite and Austenite Phases in Duplex Stainless Steels

The PREN value of the alloy may lead to a misleading prediction of pitting corrosion resistance because in the event of an imbalance of δ ferrite and austenite volume fraction, by Quantitative metallographic analyzes. In this work three laminated duplex stainless steels with different PRENs were characterized: UNS S32304 (Lean Duplex), UNS S31803 (Duplex) and UNS S32750 (Super Duplex), where several techniques of microstructural analysis were used, such as optical emission spectrometry, optical microscopy and scanning electron microscopy/EDS. For all the alloys studied, it was observed that the δ ferrite phase presents higher Cr and Mo contents than the austenite phase, which in turn had Ni contents higher than the δ ferrite. Therefore we can observe that the PRENN values for the Super Duplex alloy were generally higher, as well as in the ferritic and austenitic phase, at a level of 12.25% in relation to Duplex, and more than 50% higher than Lean Duplex, which leads to the definition of the alloy having greater resistance to pitting corrosion.