High Molybdenum Content Research Articles

Digital Light Processing Followed by Pressureless Sintering of Metal-Reinforced Ceramics: Adjustment of Process Parameters and Correlation with Composites Properties

AbstractDigital light processing (DLP) belongs to additive manufacturing techniques and is frequently used in shaping ceramics. The paper concerns the adjustment of the DLP method to metal-reinforced ceramics, especially dispersions containing high concentrations of Al2O3 (45 vol%) and molybdenum or nickel particles (0.5 vol%). Different glycol acrylates, deflocculants (polyelectrolytes and diammonium hydrogen citrate), and photoinitiators (Omnirad group) were examined regarding their influence on the rheological properties of the dispersions and the cure depth under the external halide UV lamp and LED projector built into the 3D printer. In the examined systems, the cationic polyelectrolyte KD1 dissolved in 2-butanone allowed to obtain dispersions of the lowest viscosity. Printing parameters (light exposure time, single layer height) were matched, and the properties of the materials were examined. The Vickers hardness of the sintered bodies equalled 19.4 GPa, 14.5 GPa and 17.3 GPa for Al2O3, Al2O3-Ni and Al2O3-Mo samples, respectively. The microstructure was analyzed using SEM, followed by EDS and XRD. The addition of only 0.5 vol% of Ni has improved the fracture toughness of alumina by up to 36–40% (according to Niihara and Anstis equations). The exemplary objects in the form of cog wheels were printed and densified at 1550 °C in a reductive atmosphere of Ar/H2.

Out of the blue: Hyperaccumulation of molybdenum in the Indo-Pacific sponge Theonella conica.

Molybdenum is an essential micronutrient, but because of its toxicity at high concentrations, its accumulation in living organisms has not been widely demonstrated. In this study, we report that the marine sponge Theonella conica accumulates exceptionally high levels of molybdenum (46,793 micrograms per gram of dry weight) in a wide geographic distribution from the northern Red Sea to the reefs of Zanzibar, Indian Ocean. The element is found in various sponge body fractions and correlates to selenium. We further investigated the microbial composition of the sponge and compared it to its more studied congener, Theonella swinhoei. Our analysis illuminates the symbiotic bacterium Entotheonella sp. and its role in molybdenum accumulation. Through microscopic and analytical methods, we provide evidence of intracellular spheres within Entotheonella sp. that exhibit high molybdenum content, further unraveling the intricate mechanisms behind molybdenum accumulation in this sponge species and its significance in the broader context of molybdenum biogeochemical cycling.

Valorization of biomass bottom ash in alkali-activated GGBFS-fly ash: Impact of biomass bottom ash characteristic, silicate modulus and aluminum-anodizing waste

Growing production of green energy from biomass has led to a surge in biomass bottom ash (BBA) generation, often relegated to landfills due to high leachable heavy metal content. This study proposed solidifying BBA in alkali-activated granulated ground blast furnace slag (GGBFS) and class F fly ash (CFA) blended binders. Investigations into the influence of BBA content, fineness, silicate modulus of activators, and aluminum-anodizing waste (AAW) on solidification performance were conducted, focusing on reaction mechanisms, phase assemblages, mechanical properties and leaching behavior. Results indicate relatively low reactivity of BBA and high leachable chloride (Cl-), sulphate (SO42-), chromium (Cr), molybdenum (Mo), lead (Pb) and zinc (Zn) contents from BBA. Increased BBA substitution leads to strength deterioration, while ground biomass bottom ash (GBBA) improves the mechanical performance slightly. This improvement is attributed to the increased reactive aluminosilicate content and an enhanced packing system resulting from finer particles. However, GBBA induces an increased heavy metals leaching. Higher silicate modulus activators enhance mechanical properties and reduce the leaching of Mo and Cl-, while lower silicate modulus activator accelerates the reaction process, promoting the formation of hydrotalcite-like phases and reducing the leaching of Cr and SO42-. Incorporating 0.5 wt% aluminum-anodizing waste improves immobilization efficiency of toxic ions, but further increases in dosage lead to higher leaching due to weakened mechanical performance. Overall, hybrid binders with 10 wt% G/BBA exhibit desirable mechanical properties, along with sufficient immobilization of leachable heavy metals, enabling their use as potential construction materials.

Distribution of urinary trace element exposure and dietary sources in women over 50 in an agricultural region- A community-based KoGES cohort study

BackgroundThere is a noticeable lack of information on the levels of both non-essential and essential trace elements in women aged over 50. The main objective of this study is to investigate trace element concentrations and explore the influence of sociodemographic factors and dietary sources of exposure in this demographic. MethodsWe analyzed 19 trace elements, including manganese, cobalt, copper, zinc, molybdenum, chromium, nickel, arsenic, strontium, cadmium, tin, antimony, cesium, barium, tungsten, mercury, thallium, lead, and uranium, using ICP-MS and mercury analyzer. Urine samples were obtained from a cohort of 851 women aged over 50 who participated in the 8th KoGES-Ansung study (2017–2018). Multiple linear models were employed to explore associations between urinary trace element concentrations and sociodemographic factors and dietary sources of exposure. We used K-means clustering to discern patterns of exposure to trace elements and identify contributing factors and sources. ResultsOur findings indicate higher concentrations of molybdenum (Mo), arsenic (As), cadmium (Cd), and lead (Pb) in our study population compared to women in previous studies. The study population were clustered into two distinct groups, characterized by lower or higher urinary concentrations. Significant correlations between age and urinary concentrations were observed in Ni. Smoking exhibited positive associations with urinary Cd and As. Associations with dietary sources of trace elements were more distinct in women in the high-exposure group. Urinary antimony (Sb) was positively linked to mushroom and egg intake, As to mushroom and fish, and Hg to egg, dairy products, fish, seaweed, and shellfish. ConclusionsOur study underscores the significant gap in understanding urinary concentrations of trace elements in women aged over 50. With higher concentrations of certain elements compared to previous studies and significant correlations between age, smoking, and specific food sources, it is imperative to address this gap through targeted dietary source-specific risk management.

Alloy Design Optimization of Stainless Steel's Performance and Environmental Impact Through Taguchi‐Based Grey Relational Analysis

The current work presents an optimization approach for improving stainless steel's performance and environmental impact. A Taguchi‐based grey relational analysis is used to determine the optimal alloy design of six stainless steels (304, 316L, 904L, 2304, 2205, 2507). The alloy design of a multivariable system (C, Mn, Cr, Ni, N, Mo, and Cu) is initially formulated based on the Taguchi orthogonal array. It combines the multiperformances (pitting corrosion resistance, proof strength, tensile strength, and greenhouse gas emissions) to determine a numerical score and suggests the optimal combination of alloy contents. The results are further analyzed using a range analysis to detect the significance of each alloy parameter and its level. The results show that nitrogen plays the most important role in determining the stainless steel's combined performance. Besides, the optimum alloy design consists of a high content of nitrogen, chromium, molybdenum, and copper combined with a low content of nickel. The study has a focus on proposing the systematic approach, Taguchi‐based grey relational analysis, to optimize the stainless steel's different mechanical properties with respect to environmental impact.

Advances in Corrosion Mitigation for Waste-to-Energy Systems: Evaluating Coatings and Application Techniques

Waste-to-Energy (WTE) systems, utilizing post-recycled municipal solid waste (MSW) and other biomass materials, are proven alternatives to landfilling for sustainable waste management. These processes offer benefits such as reduced landfill space, decreased methane emissions, and minimized waste volume. However, operational challenges, specifically high-temperature corrosion (HTC) of superheater tubes, hinder their efficiency due to the presence of chlorine, alkaline salts, and sulfates. To address this issue, a range of coating techniques have been developed, with thermal spray techniques, particularly high velocity oxy-fuel (HVOF) spray, proving the most effective for protecting superheater tubes. A comparative analysis of experimental data from multiple studies indicates that coatings with Alloy 625, Alloy C-276, Colmonoy 88, FeCr, IN625, NiCr, NiCrTi, and A625 offer high corrosion resistance at relatively low material costs, with corrosion rates below 1 mm/year. High chromium, nickel, and molybdenum content coatings perform exceptionally well under high-temperature and high-chlorine conditions. Notably, T92 and P91, due to their low cost and high corrosion resistance, are strong candidates for superheater tubes operating at 550°C. While A625 demonstrates excellent corrosion resistance, its high cost limits its practicality. Ultimately, the selection of suitable coatings depends on the specific WTE plant design and operating experience. The additional cost of applying these coatings is a minor fraction of the overall financial gains, as it extends the superheater tubes' lifetime and reduces plant downtime for tube repair or replacement.

Increasing corrosion resistance of Ni-Mo composite electrodeposited coatings: Doping with boron

Corrosion-resistant Ni-Mo-B electrode posited coatings were obtained. Corrosion resistance of these coatings compared to Ni and Ni-Mo increased by ∼ 6.0 and ∼ 2.0 times, respectively. Increasing the boron content in the Ni-Mo-B coating had almost no effect on its corrosion resistance in this environment. The reduction of the corrosion rate was associated with the formation of a specific surface morphology – large, irregularly oval crystal aggregates that eliminated internal stresses and cracks caused by high molybdenum content.

Retrieval analysis of the Essure® micro insert female sterilization implant: Methods for metal ion and microscopic analysis.

The Essure® Device is a female sterilization implant comprised of four alloys (Ni-Ti, 316L SS, Pt-Ir and Sn-Ag) and Dacron fibers. As part of the mandated 522 post-market surveillance study, implant retrieval and metal-ion analysis methods were developed separate from patient clinical data, to quantify trace metal ions found in tissue and to assess implant degradation present. Three segments of tissue (proximal implant, distal implant, and tissue distal from the implant) stored in neutral buffered formalin, were retrieved. Tissue was prepared for metal ion analysis using inductively coupled mass spectrometry (ICP-MS). Implant sections from four patients, were analyzed using digital optical microscopy (DOM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Image analysis showed Sn-Ag solder corroded and elevated Sn ion levels in tissue proximal to the solder compared to tissues more remote in all cases observed. The 316L SS exhibited signs of degradation with high surface concentrations of molybdenum and chromium and low iron compared to the parent alloy. Evidence of elevated iron, chromium and nickel within the tissues and storage solutions combined with precipitation of an iron-calcium-phosphorous material on some implants indicate evidence of SS corrosion. Ni-Ti, Pt-Ir and Dacron appear to have no major damage. This study includes preliminary results as part of the ongoing 522 study and therefore no final conclusions regarding the device or patient data can be drawn from this present study until the entire 522 study is complete. STATEMENT OF SIGNIFICANCE: The Essure Device is a female sterilization implant that was implanted into approximately 750,000 women. The device is composed of polyethylene terephthalate fibers and 4 metal alloys, 316L stainless steel, Nickel-Titanium, Tin-Silver and Platinum-Iridium. Following an increase in patient reported adverse events, the FDA required a 522-post market surveillance study. As part of this study, implants are retrieved from patients via salpingectomy or hysterectomy. This study focuses on the development of the implant retrieval methods following surgery, with focus on measuring local tissue metal ions, their distribution and assessing the degradation of the implant without correlation to patient clinical condition.

Failure analysis of a stainless steel component operating inside an acid leaching reactor

In this study, we examine the failure of a stainless steel component used for the agitator of the leaching reactor of a hydrometallurgy plant. The sample was subjected to several tests, starting with the characterization of the alloy’s chemical composition followed by a study of the working environment and a detailed microscopic observation of the surface and cross-section of the sample. The specifications require the use of a 316L stainless steel which is generally used for its good corrosion resistance due its high Chromium, Molybdenum and Nickel contents in environments containing chlorides such as sea water. The results found, however, that the alloy exhibited higher amounts of carbon than specified and lower amounts of nickel, both of which affected the components corrosion resistance. The analysis of the working environment found high amounts of chlorides and sulfates to the point that even the specified alloy is not corrosion resistant enough, especially at a working temperature of 90 °C. Finally, the microscopic examination led to the root failure mechanisms which are, in this case, the intergranular corrosion which was especially effective in this case where carbon content isn’t low enough, and stress corrosion cracking which was accelerated due the multiple CaSO4 inclusions found all around the material. The extensive cracking caused by those inclusions led to the corrosive agents to seep into the material, corroding it further.

Influence on Pitting Corrosion Resistance of AISI 301LN and 316L Stainless Steels Subjected to Cold-Induced Deformation

Austenitic stainless steels that exhibit good corrosion resistance have recently found increasing applications in industry and transportation. This article addresses the influence of cold rolling and deformation on the pitting corrosion resistance of AISI 301LN and 316L stainless steels. The results indicate that the content of martensite increases as the cold rolling reduction also increases. The current work combined different techniques such as optical microscopy and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) analyses. Corrosion tests were carried out, in accordance with the ASTM standards. The results confirm that the 316L steel performed better than the 301LN, regarding pitting corrosion, even when deformed. This is due to the high molybdenum (Mo) content, which guarantees greater corrosion resistance. The conducted corrosion tests showed that the increase of cold deformation reduces the resistance to pitting and overall corrosion in both steels. It was found that the 301LN stainless steel has higher susceptibility to deformation-induced martensite and, despite the addition of nitrogen, it still has a lower performance relative to the 316L steel. The current work focused on evaluating the formation of pits and the dynamics of the microstructures of the AISI 301LN and 316L steels with their mechanical properties and corrosion resistance in a saline environment including chlorides.

Corrosion of Molybdenum-Based and Ni–Mo Alloys in Liquid Bismuth–Lithium Alloy

Bismuth–lithium alloys are considered primary candidates for the reductive extraction step in the on-line reprocessing of molten salt reactor fuel. The corrosion behavior of molybdenum-based alloys and Hastelloy® B-3 alloy (taken for comparison) was examined here in a liquid Bi–Li (5 mol.%) alloy at 650 °C. MoW10, MoW30, and TZM corrosion-resistant alloys were studied as prospective construction materials for holding liquid bismuth–lithium alloy. Rates of corrosion were determined by the gravimetric method as well as by chemical analysis of corrosion products formed in liquid-phase Bi–Li alloy. The microstructure and chemical composition of samples of the materials and Bi–Li alloys containing the corrosion products after the tests were determined using inductively coupled plasma–atomic emission spectroscopy, X-ray fluorescence analysis, scanning electron microscopy, and energy dispersive spectroscopy. TZM molybdenum-based alloy corrodes in the bismuth-lithium alloy due to the formation of a zirconium–bismuth intermetallic compound, which passes into the liquid phase. The corrosion rates of MoW10, MoW30, and TZM alloys at 650 °C were 16, 16, and 23 µm/year, respectively. Hastelloy® B-3 alloy, despite its high molybdenum content, was subjected to severe corrosion in liquid Bi–Li alloys due to dissolution of nickel in liquid bismuth. The corrosion rate of this alloy was 14 mm/year.

The Effect of High Silicon and Molybdenum Content on the Mechanical Properties and Microstructure of Gray Cast Iron

This paper presents an overview of the current knowledge concerning SiMo ductile cast iron begins by describing the standard type of ductile cast iron before proceding to description of its microstructures. The paper then presents its chemical composition and the significant influence of individual elements on technological and mechanical properties. The research section focuses the influence of the addition of Si and Mo to the matrix of gray iron. After casting, stepped samples were carried out on the microstructure along with UTS tensile strength tests. The research presented in the article is a preliminary step towards the goal of obtaining a stable production process for silico-molybdenum cast iron.

Oxidation kinetics and mechanism of nickel alloys

The study covers the effect of alloying elements on the kinetics and mechanism of oxidation at 1150 °С for 30 hours of heat-resistant nickel alloys obtained using such technologies as centrifugal SHS metallurgy (SHS(M)), vacuum induction melting (VIM), elemental synthesis (ES), hot isostatic pressing (HIP). A comparative analysis was carried out for alloys based on nickel monoaluminide and standard AZhK and EP741NP alloys. It was found that kinetic dependences are described mainly by parabolic approximation. The logarithmic law of oxidation with the rapid (within 3–4 hours) formation of the primary protective layer is typical for alloys doped with molybdenum and hafnium. In the case of AZhK and EP741NP, oxidation proceeds according to a parabolic law at the initial stage (2–3 hours), and then according to a linear mechanism with the voloxidation and complete destruction of samples. Oxygen and nitrogen diffusion proceeds predominantly along the nickel aluminide grain boundaries and it is limited by the Al2O3 + Cr2O3 + XnOm protective film formation. SHS(M) alloys feature by a positive effect of zirconium and tantalum added as dopants on heat resistance. The Ta2O5 phase is formed in the intergranular space, which reduces the rate and depth of oxidation. The zirconium-containing top layer Al2O3 + Zr5Al3O0.5 blocks the external diffusion of oxygen and nitrogen, thereby improving heat resistance. Doping with hafnium also has a positive effect on oxidation resistance and leads to the formation of submicron and nanosized HfO2 inclusions that suppress the grain boundary diffusion of oxygen. MoO3, Mo3O4, CoMoO4 volatile oxides are formed in alloys with a high content of molybdenum and compromise the protective layer integrity. A comparative analysis of the oxidation kinetics and mechanism for samples consisting of the base β-alloy with Cr + Co + Hf additives showed a significant effect on the heat resistance of the sample preparation method. As the proportion of impurity nitrogen decreases and the Cr2O3 sublayer is formed, the oxidation mechanism also changes.

Microhardness and heat-resistance performance of ferromagnetic cobalt-molybdenum nanocrystals electrodeposited from an aqueous solution containing citric acid

Using a potentiostatic electrodeposition technique, nanocrystalline cobalt-molybdenum (Co-Mo) superalloys containing molybdenum oxide (MoOX) were synthesized from an aqueous solution containing citric acid. Molybdenum content in the alloys was controlled up to approximately 53% by adjusting the cathode potential during the alloy electrodeposition. Based on the XRD profiles and electron diffraction patterns, an amorphous-like nanocrystalline structure was observed in the alloys with high molybdenum content. XPS analysis revealed that the chemical state of electrodeposited molybdenum was almost metallic and the oxide state was also detected partially. According to the magnetization curves, the coercivity of electrodeposited Co-Mo alloys decreased down to approximately 72 Oe with increasing the molybdenum content up to around 53%. The microhardness reached 845 kgf mm−2 in the electrodeposited Co-53%Mo alloy and greatly exceeded that of pure cobalt (ca. 250–300 kgf mm−2). Heat resistance performance of the electrodeposited nanocrystalline Co-53%Mo alloy was improved by the Mo alloying effect because the recrystallization and oxidation behavior were not observed even if the annealing temperature was increased up to 700 °C.

Temperature effect and alloying elements impact on the corrosion behaviour of the alloys exposed to molten carbonate environments for CSP application

This investigation assesses the effect of the alloy composition and temperature in the corrosivity of the ternary carbonate eutectic, 32% Li2CO3, 33% Na2CO3, 35% K2CO3. To this end, an iron-based alloy, coded as 51Fe-24Cr-20Ni, and a nickel-based alloy, coded as 5Fe–23Cr-58Ni-8Mo, were exposed to the carbonate mixture for 500 h at 700 ºC, 750 ºC and 800 ºC under static atmospheric air. The results revealed that corrosion extension does not have a linear dependence on temperature. There are changes in the corrosion mechanism that depend on the temperature, but, in turn, they are directly influenced by the alloying elements of the material. The performance of the nickel-based substrate proved to be catastrophic at all the studied temperatures. The order from worst to best was 700 ºC > 750 ºC > 800 ºC. The presence of a high molybdenum concentration in the carbonate mixture in contact with this nickel-based alloy suggested that this element dissolution contributes to increasing the corrosivity of the mixture. By contrast, the iron-based alloy showed improved corrosion resistance, with an estimated corrosion rate in the order of hundreds of microns at the three temperatures. The best performance of the 51Fe-24Cr-20Ni alloy was achieved at 700 ºC, followed by that at 800 ºC, while the highest degradation was registered at 750 ºC. This investigation reinforced the idea of the complexity of the corrosion processes in molten carbonate. The equilibrium of corrosive species is very sensitive to an important number of parameters, meaning that modifications in the system conditions have a great impact on corrosivity. Hence, it is critical not to make assumptions when considering potential materials for carbonate containment in CSP technology.

An assessment of protective coating dry cask canisters with structurally amorphous metals (SAMs) for enhanced radiation shielding

The shielding properties of the most common structurally amorphous metals (SAMs) as coating barriers for radiation shielding and corrosion have been computationally studied, for possible use on spent fuel dry cask canisters applications, using the Microshield computational simulation package. The results revealed that SAM1651 exhibited the highest attenuation coefficients and lowest exposure rates at low photon energies, which is attributed to its high elemental content of molybdenum (Mo) and yttrium (Y), while SAM2X5 exhibited the highest attenuation coefficients and lowest exposure rates at high photon energies, due to its high density (7.6 g/cm3) and its elemental content of manganese (Mn), tungsten (W) and silicon (Si). The third SAM material known as SAM 40 had the highest iron content (52.3%), but the results were close to the SAM2X5 as other components were similar, however, SAM2X5 was of higher density. The mean-free path (MFP) and half-value layer (HVL) were very similar for all the three tested SAM materials.

Ferrite and Carbide Mixtures in Sintered Hyper-Eutectoid Fe-xMo-0.90C Alloys

Phase transformations in low- to medium-carbon Fe-Mo-C alloys have been widely investigated for decades and fruitful information regarding phase transformation is available. However, hyper-eutectoid Fe-Mo-C alloys were least studied. Metallurgical information regarding high-carbon Fe-Mo-C alloys is rarely available. In this work, high-carbon Fe-xMo-0.90C alloys (x = 0.50, 0.85 and 1.50 wt%) were prepared by sintering powder compacts made from pre-alloyed Fe-Mo admixed with 0.90 wt% graphite. Phase transformations in experimental sintered alloys were studied under two different cooling rates, e.g. 0.1 and 5.4 °C/s. Under the cooling rate, phase transformation products were controlled by molybdenum content. In all slowly cooled sintered alloys, phase transformations involved with eutectoid decomposition. The eutectoid transformation products, simply ferrite and carbide mixtures in the form of upper bainite, were generally observed in all slowly cooled sintered alloys. The nodular bainite and inverse bainite coexisted with upper bainite in slowly cooled sintered alloys with higher molybdenum contents. Under the fast cooling rate, fine pearlite and upper bainite were the common transformation products. In addition, in fast cooled alloys with the higher molybdenum contents, inverse bainite formed as one of the transformation products.

Lithogeochemical and isotopic characterization of Devonian molybdenite mineralization in the Pabineau Falls Granite, northeastern New Brunswick, Canada

An unusual molybdenite occurrence in northeastern New Brunswick, referred to herein as the Pabineau Lake Mo (PLM), is situated to the south of Bathurst. This occurrence consists of high-grade molybdenite-bearing granites that occur within the large Pabineau Falls Granite (PFG). To help evaluate the evolution of this occurrence, a large composite sample containing disseminated, very coarse molybdenite (up to 5.02 wt% MoS2) was collected from mineralized granitic blocks excavated from a blasted trench. Although the host rocks are assumed to be PFG, being the only defined intrusive body in the area, major- and trace-element geochemical data together with U-Pb geochronological results suggest that the molybdenite is hosted by an intrusion distinct from the PFG. The radiogenic Sr-Nd-Hf-Pb isotopic data of the host intrusion are consistent with Gander Zone granites of the Appalachians orogenic system.The PLM's granitic host rock is characterized by a high silica content (78.93 wt% SiO2), an enrichment in incompatible elements, and a high molybdenum content. The high initial 87Sr/86Sr of 0.71268, negative εNd of −1.28, and high Pb isotope ratios together with trace- and major-element concentrations indicate a moderately to highly radiogenic Sr source and derivation from a significant amount of supracrustal materials, with a contribution from the upper mantle; a source similar to that proposed for the Gander Zone Siluro-Devonian granitic bodies. A positive εHf (+1.34) also suggests involvement of sedimentary components. This is consistent with elevated Cr (20 ppm) and Ni (20 ppm). The involvement of a pelagic sedimentary component is invoked to explain the enrichment in elements commonly associated with mafic compositions.A new precise, LA ICP-MS zircon crystallization age of 390±1 Ma makes the PLM host granite Middle Devonian, which argues against a direct relationship with the older PFG (397.2±1.9 Ma). The new age opens the possibility of an as yet undelineated, mineralized intrusion within the Gander Zone, which has perhaps been missed during previous investigations due to the extensive glacio-fluvial cover and very limited bedrock exposures. Alternatively, the younger age could be attributed to very slow cooling and/or intra-pluton fractionation, resulting in a younger much more fractionated phase of the PFG. However, there is no geochemical evidence for such a prolonged continuous fractional crystallization process.Notably, recent geophysical surveys on the Bathurst Mining Camp indicate that the PFG is substantively larger than its surface expression as it continues to the east beneath the Carboniferous unconformity.Comparing ages of PLM and PFG with the nearby Nicholas-Denys Granodiorite (381±4 Ma) and Antinouri Lake Granite (372±4 Ma), it appears that magmatic activity in the region occurred every 10 Myr over a span of about 30 Myr.Collectively, this evidence suggests the potential of significant buried intrusions within this tectonic belt of the Gander Zone. At the PLM, this might include exposure of an otherwise hidden intrusion that is younger and much more fractionated than the PFG. More detailed geophysical and geochemical analyses would be required to revise the current geological map and, most importantly, trace unmapped units at depth to possible additional mineralized sequences.

Evaluation of Strength and Microstructural Properties of Heat Treated High-Molybdenum Content Maraging Steel

Effect of high molybdenum content ~10% as an alloying element on the strength and microstructural properties of 11% nickel—1.25% titanium maraging steel was evaluated. To increase the homogeneity and cleanliness of produced ingot, the investigated steel sample was produced by melting the raw material in an open-air induction melting furnace followed by refining utilizing a direct current electro-slag refining machine. The produced steel samples were both forged and heat-treated in optimum condition to acquire the full capacity of mechanical properties especially the tensile properties. After Forging and heat treatment at optimum condition, steel samples were evaluated by optical microscopy (OM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) analysis, electron backscattering diffraction (EBSD), and transmission electron microscopy (TEM). The experimental data showed that this steel sample has ultimate strength ~2100 MPa and elongation around 14%. High tensile properties obtained may be attributed on one hand due to the presence of high alloying lamellar martensite phase and lamellar austenite phase which has high dislocation intensity, and on the other hand, due to the high homogeneity and cleanliness of investigated samples from large nonmetallic inclusions. The results also show that a high amount of intermetallic compounds (NiMo3 and NiTi3) which are completely round and have a very low size not more than hundred nanometers.

Rapid and sustained environmental responses to global warming: the Paleocene–Eocene Thermal Maximum in the eastern North Sea

Abstract. The Paleocene–Eocene Thermal Maximum (PETM; ∼ 55.9 Ma) was a period of rapid and sustained global warming associated with significant carbon emissions. It coincided with the North Atlantic opening and emplacement of the North Atlantic Igneous Province (NAIP), suggesting a possible causal relationship. Only a very limited number of PETM studies exist from the North Sea, despite its ideal position for tracking the impact of both changing climate and NAIP activity. Here we present sedimentological, mineralogical, and geochemical proxy data from Denmark in the eastern North Sea, exploring the environmental response to the PETM. An increase in the chemical index of alteration and a kaolinite content up to 50 % of the clay fraction indicate an influx of terrestrial input shortly after the PETM onset and during the recovery, likely due to an intensified hydrological cycle. The volcanically derived zeolite and smectite minerals comprise up to 36 % and 90 % of the bulk and clay mineralogy respectively, highlighting the NAIP's importance as a sediment source for the North Sea and in increasing the rate of silicate weathering during the PETM. X-Ray fluorescence element core scans also reveal possible hitherto unknown NAIP ash deposition both prior to and during the PETM. Geochemical proxies show that an anoxic to sulfidic environment persisted during the PETM, particularly in the upper half of the PETM body with high concentrations of molybdenum (MoEF > 30), uranium (UEF up to 5), sulfur (∼ 4 wt %), and pyrite (∼ 7 % of bulk). At the same time, export productivity and organic-matter burial reached its maximum intensity. These new records reveal that negative feedback mechanisms including silicate weathering and organic carbon sequestration rapidly began to counteract the carbon cycle perturbations and temperature increase and remained active throughout the PETM. This study highlights the importance of shelf sections in tracking the environmental response to the PETM climatic changes and as carbon sinks driving the PETM recovery.