Scanning Electron Microscopy Coupled With Energy Dispersive Spectroscopy Research Articles

Comparison of microstructure, mechanical, and electrochemical performance of laser-deposited FeCrV15 alloy at varying powder feed rates

In the realm of surface modification, repair, and reinforcement of components exposed to challenging operational conditions, such as tillage tools, laser cladding stands out as an innovative manufacturing technique. Employing this additive manufacturing approach, a functionally graded material with outstanding strength and properties is incorporated to enhance the desired attributes of the base material. This comparative investigation scrutinized and assessed the microstructural characteristics, hardness, wear resistance, and corrosion behavior of high carbon ferrochrome FeCrV15 coatings fabricated at two distinct powder feed rates, namely 5 and 6 g/min, respectively. The analysis delved into how the resultant coatings' molten bead deposition, microstructural evolution, hardness, wear resistance, and corrosion resistance were influenced by the powder feed rate. Evaluation of hardness was conducted using a Vickers microhardness testing apparatus, while phase identification was accomplished utilizing an X-ray diffractometer. The morphologies of the microstructures were scrutinized employing optical microscopy and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS). Furthermore, the corrosion response of the deposits in a soil–water environment was probed utilizing an Autolab potentiostat. A comprehensive assessment of the coatings' sliding wear performance was undertaken using an Anton Paar Tribometer. The findings of the study reveal that an escalation in the powder feed rate engenders heightened grain refinement within the microstructure, yielding a defect-free sample and augmenting the wear performance (with a wear rate of 2.42 × 10–6 mm3/N/m for sample B, surpassing 2.39 × 10–5 mm3/N/m for sample A and outstripping 1.72 × 10–3 mm3/N/m for the steel substrate). Additionally, the corrosion resistance is enhanced (with a corrosion rate of 0.0032 mm/yr for sample B, surpassing 0.0036 mm/yr for sample A, which, in turn, exceeds 0.1168 mm/yr for the steel substrate) in the case of sample B.

Preparation of a nano aluminum phosphate enhanced hydroxyapatite coating for marble conservation

Open-air marble relics in Beijing are experiencing degradation due to sugaring, dissolution and other illnesses. Therefore, it is necessary to apply a protective and reinforcing coating to the weathered surface. Hydroxyapatite (HAP) has significantly lower solubility and dissolution rate compared to calcite. Additionally, HAP has similar lattice parameters with calcite, suggesting that a cohesive layer of HAP can be formed over calcite. In fact, HAP exhibits a lattice mismatch of 5 % with calcite, which might potentially lead to stress if the layer exceeds a few nanometre in thickness. On the other hand, aluminum phosphates (ideally, B-AlPO4) only exhibit a 1 % mismatch with calcite and have a solubility lower than that of calcite. In this study, in order to improve the property of HAP in marble conservation, sol–gel method was employed to synthesize nano AlPO4, which were then incorporated into the phosphate solution to produce protective coating on the stone surface. The coatingʼs morphology and the structure were characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), high capacity 3D X-ray microscopy (XRM), optical microscope, and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). Moreover, the color, the contact angle, the three-point bending strength measurements, as well as the simulated acid rain test and freeze–thaw treatment were performed to assess the chromatic aberration, hydrophilicity, reliability, and durability of the coating. Results indicated that the nano AlPO4, with its matched lattice parameters and nucleation site provision, facilitated the formation a coherent HAP layer of crystal flakes. Subsequently, the anti‑corrosion property, freeze-thaw resistance and consolidation property of the coating were improved, demonstrating the potential application the hybrid of HAP with nano AlPO4 in the preservation of marble.

Black Crust from Historic Buildings as a Natural Indicator of Air Pollution: A Case Study of the Lipowiec Castle, Babice, Southern Poland

The study is focused on the analysis of black crust and soiling on the building materials of the medieval Lipowiec Castle in southern Poland. The castle was constructed using local, partly dolomitic limestones and dolomites, supplemented with other limestones and bricks, during 20th-century renovations of the castle ruins. The crust and soiling components, secondary mineral phases, and particulate matter of anthropogenic origin were analysed using Raman micro-spectroscopy (RS) and scanning electron microscopy coupled with energy-dispersive spectrometry (SEM-EDS). The crust, mostly composed of gypsum and other sulphate phases, was found to contain carbonaceous matter, spherical Si-Al glass particles, and iron oxides, with admixtures of other elements, including heavy metals, as well as irregularly shaped particles containing various metals. These components reflect the air pollution in the region, related to the combustion of solid fuels in both industrial power plants and local domestic furnaces, Zn-Pb ore mining (operational until 2021), and smelting in the neighbouring industrial centre. Despite its location in a rural area, the castle has been exposed to pollution for an extended period due to its proximity to large industrial centres. Therefore, the crust analysed may serve as an environmental indicator of the nature of the air pollution in the region.

Properties, Bioactivity and Viability of the New Generation of Oxyfluoronitride Bioglasses

In this study, the deposition of apatite on the surface of the glasses with a composition of 22.25Na2O–13.5CaO–2.5P2O5–6.75CaF2–(55−3x) SiO2–xSi3N4 (x is the no. of moles of Si3N4) (where x = 0-4), was studied to examine the influence of nitrogen content on their properties, bioactivity and viability. It was established that density, glass transition temperatures, Young’s modulus of elasticity, Vicker’s microhardness and fracture toughness increased significantly with increasing nitrogen concentration. Bioactivity was investigated by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Hydroxyapatite (HCA) layer thickness was determined using a scanning electron microscope coupled with Energy Dispersive Spectroscopy (SEM-EDS). The bioactivity of the glasses was evaluated by dipping them in a simulated body fluid (SBF) and demonstrated that all glasses are bioactive. Cytotoxicity tests using different concentrations of bioglass powders in a cell growth environment further demonstrated that they were not cytotoxic. The biofilm formation by two bacteria’s E. coli and S. marcescens was characterized by the absorbance of crystal violet. The influence on the presence of bacteria in the form of biofilms appears to be affected by the combination of two main factors: glass reactivity and nitrogen content. Additionally, the type or characteristics of the bacteria also play a significant role in this context.

The role of phosphate in inhibiting the activation of quartz flotation induced by Mg2+

As a common gangue in many mineral flotation processes, the activation of quart by inevitable cations will worsen the flotation separation of valuable minerals from quartz. In this work, phosphate was selected to inhibit the activation of quartz flotation by Mg2+, and the role of PO43− during flotation was deeply studied by density functional theory (DFT) calculation and a series of research methods. Micro-flotation experiments demonstrated the strong activation effect of Mg2+ on quartz at pH 10, and the activation effect was significantly inhibited upon adding PO43− to the flotation solution. DFT calculation predicted that Mg hydroxyl compounds (MgOH+ and Mg(OH)2) were easily adsorbed onto quartz surface, while Mg3(PO4)2 generated from the reaction between PO43− and Mg2+ would not be adsorbed onto the quartz surface, which was supported by zeta potential measurement, X-ray photoelectron spectroscopy (XPS) detection, and, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) test. Fourier transform infrared spectroscopy (FTIR) tests indicated that the Mg hydroxyl compounds adsorbed onto quartz surface would induce the adsorption of NaOL, which was responsible for the activation of quartz flotation. The addition of PO43− to flotation solution containing Mg2+ could effectively inhibit the generation of Mg hydroxyl compounds and the subsequent adsorption of NaOL, thereby achieving the depression of quartz flotation. This work provided an effective way for the depression of quartz flotation in complicated flotation systems.

Forged soft tissues revealed in the oldest fossil reptile from the early Permian of the Alps

AbstractTridentinosaurus antiquus represents one of the oldest fossil reptiles and one of the very few skeletal specimens with evidence of soft tissue preservation from the Cisuralian (Early Permian) of the Italian Alps. The preservation and appearance of the fossil have puzzled palaeontologists for decades and its taphonomy and phylogenetic position have remained unresolved. We reanalysed T. antiquus using ultraviolet light (UV), 3D surface modelling, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM‐EDS), micro x‐ray diffraction (μ‐XRD), Raman and attenuated total reflectance Fourier transformed infrared (ATR‐FTIR) spectroscopy to determine the origin of the body outline and test whether this represents the remains of organically preserved soft tissues which in turn could reveal important anatomical details about this enigmatic protorosaur. The results reveal, however, that the material forming the body outline is not fossilized soft tissues but a manufactured pigment indicating that the body outline is a forgery. Our discovery poses new questions about the validity of this enigmatic taxon.

Study of Mg–Fe content in tourmalines from the dravite–schorl series by Raman spectroscopy

AbstractThanks to their high chemical and mechanical stability, their diffusion in all types of detrital sediments and their complex structural formula (XY3Z6(T6O18)(BO3)3V3W), tourmalines have attracted strong interest in provenance studies since, from their chemical composition, it is possible to reconstruct the source rocks in ancient sediments. Dravite and schorl, belonging to the alkali subgroup 1, are the most abundant tourmaline species, and they have different Y‐site compositions in the unit cell: dravite has more magnesium, while schorl has a higher iron content. For this reason, it is important to measure the Mg–Fe relative content in order to classify the analysed tourmalines in the dravite–schorl series. Raman spectroscopy is a suitable technique as it allows quick and easy measurements that provide chemical and structural information on tourmalines with a high spatial resolution, thus allowing analysis of small grains that could be found in sediments. In this work, we correlated the relative Mg–Fe content (x = Mg/(Mg + Fe)) in different tourmaline samples from the dravite–schorl series ( ) with variations in Raman spectrum parameters in order to find a model for quick tourmaline identification useful for provenance studies. The chemical compositions of the analysed tourmalines are obtained by scanning electron microscope coupled with energy‐dispersive spectroscopy (SEM‐EDS). Raman measurements with a portable spectrometer have also been performed in order to evaluate our results for in situ applications.

Physicochemical properties of clayey deposits slurry treated by lime-activated ISSA and GGBS considering seawater salinity effect

This study sheds light on the engineering and environmental performance of lime-activated incinerated sewage sludge ash (ISSA) and ground granulated blast furnace slag (GGBS) treated Hong Kong marine deposits (HKMD) slurry by stabilisation/solidification (S/S) technology, which is proposed using as fill materials in reclamation projects. The S/S performance of the treated HKMD with distilled water and seawater under different salinities was investigated. The results show that seawater could help S/S treated HKMD gain strength by using activated industrial wastes (ISSA and GGBS). The hydration and pozzolanic reactions between ISSA, GGBS, CaO and clayey compositions in HKMD make contributions to the strength development, porosity decrease and heavy metals stabilisation, which is supported by the characterization analysis including thermo-gravimetric (TG) analysis, mercury intrusion porosimetry (MIP) tests, nitrogen adsorption/desorption isotherms (NAI), scanning electron microscopy coupled with energy-dispersive spectrometry (SEM-EDS) and the leaching test of toxicity characteristic leaching procedure (TCLP). Seawater of 1.8% salinity (18 g/kg) is better than the distilled water and seawater of 3.6% salinity as a substrate solution in the S/S treated HKMD, because of the highest unconfined compressive strength and lowest porosity in the treated samples. The highest pH may account for its highest strength under the 1.8% salinity conditions. The S/S process could effectively stabilize the contaminants regardless of the curing time and the salinity of the mixing solution, and the leachates from the stabilized HKMD are environmentally safe and meet the requirement of standard in Hong Kong on the recycling treated soil. Therefore, recycling wastes—ISSA and GGBS with lime can be used as an appealing binder to stabilize/solidify marine deposits as environmental-friendly reusable materials in reclamation projects.

THE APPLICATION OF SEM-EDS FOR THE SURFACE TEXTURE OF FORAMINIFERA: IDENTIFICATION OF EARLY DIAGENESIS OF REWORKED L. DIMIDIATUS WITHIN MODERN COASTAL DEPOSITS

Sediment recycling has been known to occur within Quaternary coastal barriers of the greater Coorong Coastal Plain, southern Australia. A high degree of reworking of skeletal carbonates from Late Pleistocene deposits (Robe Range) is evident based on the novel application of amino acid dating of the single-foraminifera species Lamellodiscorbis dimidiatus. More importantly, some apparently transparent, well-preserved tests indicate anomalously high extents of amino acid racemization, implying that reworked fossils could not be easily distinguished based on taphonomic signatures such as corrosion. Here, we examine the surface microtexture of this species, constrained with well-preserved specimens, on a modern beach of Canunda, southern Australia, using scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). The aim is to identify surface features of foraminifera in more detail, capturing signs of early diagenesis associated with weakly consolidated Late Pleistocene coastal barriers. The results reveal that some well-preserved tests show localized blocky calcite cementation, most notably within intraseptal spaces or impact sites. The EDS spectra of cement indicate lower Mg content than unaltered foraminifera surface. This suggests low-Mg calcite precipitation due to meteoric diagenesis experienced by the onshore Late Pleistocene coastal barrier. It implies that these foraminifera shells are reworked fossils originated from older successions and were subsequently redeposited within the present-day beach. SEM-EDS used in this study demonstrates its capability in examining small-scale carbonate diagenesis products beyond the traditional binocular microscope. Thus, this tool is recommended to aid amino acid dating in detecting reworked fossils.

A critical catalogue of SEM-EDS multispectral maps analysis methods and their application to hydrated cementitious materials.

Many methods have been proposed to analyse SEM-EDS hypermaps of hydrated cementitious materials but none can fit all purposes. In this presentation, we review existing methods for phase identification, stoichiometry quantification, and microstructure quantification in cementitious materials and related materials. We first discuss the unique contribution of SEM-EDS with respect to the outstanding scientific challenges towards sustainable construction materials. We then compare the SEM-EDS and image analysis techniques which contribute to answering these challenges. Convergence and divergence in current methods and workflows, and knowledge gaps are highlighted in terms of the specificities of the material (phase assemblage complexity, grain sizes, mixtures, etc.). The discussion is weighted by the required expert knowledge for the sample preparation, microscope operation, and data analysis. We conclude by discussing how microscopy and image analysis integrate into the overall experimental toolkit to investigate and improve cementitious materials.

Development of Synthesis Strategy of Ferric and Clayey Flat Ceramic Membranes

Ceramic membranes prepared with flat sheet configuration using local materials, iron ore and bentonite, are reported in this investigation. The feedstocks used were fully characterized using X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) and laser diffraction/light scattering. In order to optimize the preparation conditions, the effect of sintering temperature on the microstructure of ferric and clayey membranes was assessed. Results obtained with SEM, confirmed by optical microscopy, indicate that the optimized sintering temperature was in the vicinity of 900 °C. The properties of the fabricated membranes were characterized in terms of mass and thickness loss throughout a determined period of time. The experimental results present a negligible variation in the rate of mass change, which suggested the stability of the synthesized membranes. Both the ferric and clayey membranes exhibit a prevalence of mesopores in their pore distribution. These results suggest that these specific membranes could be employed as cost-effective and environmentally friendly materials. Furthermore, they hold promise for potential applications in gas treatment processes.

MOF-templated CuO and Mn[sbnd]CuO/Cu2O composites as electrocatalyst in oxygen evolution

Considering the great need for the development of new electrocatalysts for oxygen evolution reaction (OER), this work reports the synthesis and characterization of four new copper-based electrocatalysts derived from metal–organic frameworks (MOFs). Homometallic (CuIDA, [Cu(IDA)(H2O)2]n IDA= iminodiacetate) and heterobimetallic [Cu0.902Mn0.096(IDA)(H2O)2]n, [Cu0.703Mn0.297(IDA)(H2O)2]n and [Cu0.487Mn0.513(IDA)(H2O)2]n MOFs were obtained by precipitation method and characterized by X-ray diffraction (XRD) with Rietveld refinement, infrared spectroscopy (FT-IR) and thermogravimetric (TGA). The calcination of CuIDA and heterobimetallic MOFs under air atmosphere led to the formation of CuO and CuO/Cu2O/Mn-x (x = 10 %, 20 % and 50 % of Mn) electrocatalyst, respectively. These materials were characterized by XRD, FT-IR, Raman spectroscopy, UV–vis spectroscopy and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), confirming the chemical composition and crystal structure. Copper oxide-based materials were applied as electrocatalyst for OER in alkaline medium, with overpotential of 359 mV (CuO), 355 mV (CuO/Cu2O/Mn10), 360 mV (CuO/Cu2O/Mn30) and 355 mV (CuO/Cu2O/Mn50) to record a current density of J = 10 mA cm−2. Tafel slope values indicate the adsorption of intermediate species as the rate-determining step for all electrocatalysts. These results are similar or superior to those found in the literature so far.

Experimental Characterization of a Novel Foam Burner Design for the Low-Excess-Enthalpy Combustion of Very Lean Syngas Mixtures

In the present work, a novel foam burner design is proposed and experimentally evaluated for operation with highly diluted syngas mixtures. The lab-scale burner consists of a purpose-built, square-shaped, high-temperature-grade stainless steel tubular reactor filled with square-sectioned siliconized silico carbide (SiSiC) foams. The assembly was installed in an electrical furnace. Spatially resolved temperature measurements were obtained along the reactor axis, while simultaneous measurements of CO, CO2, H2, O2, and N2 were taken at the burner exit and the water levels were recorded upstream and downstream of the reactor. The results clearly show that flames can be stabilized along the reactor for a range of foam characteristics and operating conditions. Hydrogen conversion efficiencies in excess of 98%, and overall thermal efficiencies close to 95% were achieved for the selected operating conditions. Overall, the denser 10 ppi foam demonstrated superior combustion characteristics in terms of stability, lower enthalpy rises, and a wider operating range at the expense of a very modest pressure drop penalty. Finally, scanning electron microscopy, coupled with energy dispersion spectroscopy (SEM/EDS) and Raman spectroscopy analyses, was used to determine the morphological and compositional characteristics of the pristine and aged foams. After more than 100 h of operation, no significant performance degradation was observed, even though the burner design was subjected to considerable thermal stress.

Slags from roasting of antimony ore in the Brioude-Massiac (France) area used as aggregates: An early example of circular economy.

Towards the end of the 19th century and the early 20th century, France was the world's largest producer of antimony, especially due to the rich deposits in the Brioude-Massiac area. Even though all the mining and smelting activities are long gone, there are still some remains of those activities. The most original of those is the use of roasting slags as aggregates in former plant walls or industrial building. They are macroscopically characterised by a black or red colour with a vesicular aspect similar to natural pozzolanas. Common petrography and mineralogy tools have been used to characterise those slags: optical mineralogy, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD). To gain an insight into their mineral complexity, a QEMSCAN map has been produced. The mineralogy is typical of high-temperature slags: cristobalite, quartz, mullite, fayalite-forsterite series and spinel. The antimony content is quite high, up to seven percent, under the form of various antimony oxides and native antimony.

Preliminary Diagnostic Survey of Deteriorated Paint Layers at the Maritime Station of Rocha Do Conde De Óbidos, Lisbon: A Multianalytical Research

This paper reports the preliminary diagnostic survey of the six controversial mural paintings painted in 1946–49 at the Maritime Station of Rocha do Conde de Óbidos in Lisbon, considered the artistic epitome of Almada Negreiros mural painting art. Four research questions drove this research: a) What are the main decay phenomena present and their sources? b) Which are the paint layers most affected, and are they linked to a particular pigment? c) Is there any relation between the painting technique used and the deterioration or stability of the paint layers and pigments? And finally, d) Are there differences in the decay phenomena present in both maritime stations of Alcântara? The analytical setup comprised in-situ and laboratory analysis by way of technical photography documentation (TP), handled optical microscopy (h-OM), handheld X-Ray Fluorescence (XRF), complemented by optical microscopy of microfragments and cross sections (OM-Vis-UV), X-Ray Diffraction (XRD), and Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDS).The first results indicate flaking of the paint layers as the main and most severe deterioration feature present in most of the murals. The yellow ochres, browns, blacks, and light greens are the colours most affected, showing different degrees of loss. The pictorial technique used, the presence and action of soluble salts in the structure, and even the products used as adhesives during past interventions might be the root of this phenomenon.

Role of surface morphology in bed particle layer formation on quartz bed particles in fluidized bed combustion of woody biomass

The influence of quartz bed particle surface morphology on the bed particle layer and crack layer formation process in fluidized bed combustion of woody biomass was investigated in this work. Bed material samples were collected at different sampling times from the startup with a fresh bed in industrial scale bubbling fluidized bed (BFB) and circulating fluidized bed (CFB) boilers, both utilizing woody biomass. X-ray microtomography (XMT) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) were employed to characterize bed particle layers and crack layers in the samples. Results showed that there is a noticeable difference between the bed layer characteristics over the so-called “concave” and “convex”-shaped morphologies on the bed particle surface with respect to layer formation. The concave areas are mainly covered with a thin inner layer, whilst the convex display a comparably thick inner layer and an outer layer. In addition, 3D images of the particles revealed that the crack layers mainly originate from concave areas where the particle is less protected by an outer bed particle layer in conjunction with cracks in the inner layer.

On the structure of Ag-containing sol-gel bioactive glasses: A surface crystal growth of metallic silver removes its network modifier role in the glass structure

Ag-containing bioactive glasses (Ag-BG) have been extensively studied as a bactericidal biomaterial, produced mainly by the sol-gel method over the last decades. According to the literature, sol-gel-derived Ag-BG may show metallic or ionic silver species in the glass structure. However, most of these works lack detailed information about how the addition of silver affects the glass network. In this study, we systematically produced sol-gel derived 58S glasses containing different quantities of Ag2O (1, 5, and 10 wt%), yielding glasses with different proportions of silver species (Ag0 or Ag+1). Results from X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) evidenced the progressive formation of silver crystals due to the addition of silver in the glass structure. 29Si and 31P nuclear magnetic resonance and photoelectronic X-ray spectroscopies evidenced a glass depolymerization caused by Ag1+ addition in the glass structure. On the other hand, the presence of silver crystals (Ag0) removes the network modifier role of silver, yielding glasses with higher network connectivity. A possible mechanism to explain the formation of silver crystals was proposed based on surface nucleation and growth. Finally, we suggest understanding Ag1+ or Ag0 formation as a solution to design glasses with tuned bactericidal properties.

Inorganic component in oak waterlogged archaeological wood and volcanic lake compartments

Abstract. Waterlogged archaeological wood (WAW) is a rare and precious organic material that can hold outstanding cultural values. In order to protect WAW for the next generations, this material must be accurately characterised to set its proper conservation, storage and exhibition conditions in museum environments. In this study, the mineral content found in WAW retrieved in a volcanic lake was investigated by analysing wood ash through scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (SEM-EDS). This micro-destructive approach was coupled with morphological studies carried out through optical microscopy. SEM-EDS was also performed on the WAW and surrounding sediment to study the possible relationship between the mineral composition and the wood degradation state. The analysis revealed that calcium was the most abundant element in all poles, with weight percentages ranging between 24 % and 42 %. This element was more represented in heartwood (HW) than sapwood (SW). In sapwood the second most abundant element was arsenic. Sulfur, iron and potassium were present in all the analysed samples as well. Arsenic was also detected in the sediments; it was particularly concentrated in the samples taken near archaeological wood. The presence of this element can be linked to the volcanic origin of the lake, and its high concentration points to bioaccumulation processes induced by bacteria (erosion bacteria and sulfate-reducing bacteria) and biogeochemical processes favouring precipitation of insoluble compounds. The present work is the first investigation of the mineral content in archaeological wood establishing a contingent relationship with the surrounding volcanic lake sediments.

Electrochemical separation of fission element neodymium using plumbum electrode from molten LiCl–KCl based on spent fuel reprocessing

In order to investigate the application prospects for the extraction of fission products neodymium (Nd) by electrolytic refining at active plumbum (Pb) electrodes, the reduction mechanism of Nd(III)/Pb(II) at inert tungsten, and Nd(III) at Pb thin film electrodes was investigated. This work simultaneously presents the results of kinetic and thermodynamic parameter of Pb(II)/Nd(III). The composition of the Pb–Nd alloy compound formed on the activated Pb electrode was determined by X-ray diffraction analysis (XRD) and scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), and the thermodynamic parameters of the formed Pb3Nd alloy were calculated: ΔHf0Pb3Nd=−219.92kJmol−1 and ΔSf0Pb3Nd=−47.48Jmol−1K−1. Nd(III) was extracted in the form of Pb–Nd alloy by constant potential electrolysis (PE) in LiCl–KCl melt. Based on the analysis of inductively coupled plasma-atomic emission spectrometry (ICP-AES) results, the average extraction rate of Nd(III) ions at the liquid Pb electrode could reach 99.03%.

Crystalline Structure Assessment of Ceramic Veneered Co-Cr-W Dental Alloy Substructures Obtained by Selective Laser Melting—A Pilot Study

The aim of this work is to assess the crystalline structure modification of an SLM Co-Cr-W dental alloy, veneered with two different ceramics, by means of X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy, coupled with energy-dispersive spectroscopy (SEM-EDS). Ten identical plates were fabricated using SLM and were subsequently subjected to ceramic veneering. Following the repeated firing of the ceramic layers, carried out at temperatures exceeding 900 °C, new crystalline phases and variations in the crystallite sizes in the SLM Co-Cr-W dental alloy used for the substructure were detected via XRD. The two veneering ceramics showed significant differences in their behavior, beginning with the first firing, accompanied by structural changes. AFM micrographs and histograms of the surface heights over the whole scanned area of the samples showed that the surface of the Co-Cr-W dental alloy is strongly affected by the repeated firings necessitated by the ceramic firing process, a finding in accordance with the XRD results. The SEM investigation revealed that the different firing parameters had an impact on the alloy, the ceramic microstructure, and the surface quality. The differences in the chemical composition of the ceramics, highlighted by EDS, are reflected in their behavior. The crystalline alloy structure is influenced by the repeated firings of the ceramic layers.