Mo System Research Articles

Thermodynamic re-modeling of the binary Al–Mo and ternary Al–Fe–Mo systems based on novel experimental data

Thermodynamic re-modeling of the binary Al–Mo and ternary Al–Fe–Mo systems based on novel experimental data

High-throughput determination of interdiffusivity and atomic mobilities in bcc Ti–Cr–Mo alloys

A comprehensive understanding of the diffusion coefficients and atomic mobilities in the Ti–Cr–Mo system is crucial for establishing an atomic mobility database for titanium-based high-strength titanium alloys. In the present work, nine sets of solid/solid diffusion couples were prepared and measured in bcc Ti–Cr–Mo alloys, with the temperatures ranging from 1373 to 1473 K. Scanning electron microscopy (SEM), and Electro Probe Micro-Analysis (EPMA) techniques were used to respectively test its microstructure and composition distance. The diffusion coefficients in bcc Ti–Cr–Mo alloys were determined using the Matano-Kirkaldy method and numerical inverse method respectively. The diffusion coefficients obtained from the above two methods exhibit good consistency. The atomic mobility parameters for the Ti–Cr–Mo systems were provided with the assistance of HitDIC software. A three-dimensional plot of interdiffusivities was generated for chromium and molybdenum contents ranging from 0 to 20 mol % and 0–14 mol %. Moreover, the application of the Arrhenius equation enabled the determination of changes in frequency factors and activation energies concerning temperature and composition.

Fluid inclusion and He-Ar-Pb isotope studies of the Dabie-type Leimengou giant porphyry Mo deposit, Qinling Orogen

The Leimengou deposit is a Dabie-type porphyry Mo system in the Leimengou-Qiyugou orefield of Qinling Orogen. Orebodies host within the porphyry and the metasedimentary Taihua Supergroup. However, the characteristics and sources of ore-forming fluid, metal precipitation mechanism, and the sources of mineralizing substances remain unclear. In this contribution, by a comprehensive study comprising an investigation of deposit geology, fluid inclusion microthermometry, and He-Ar-Pb isotope, we discuss the source and evolution of ore-forming fluids and the molybdenum precipitation mechanism of the Leimengou deposit. The mineralizing process is divided into the Stage I quartz ± K-feldspar vein in potassic altered zone, Stage IIa molybdenite ± quartz vein, and Stage IIb molybdenite + quartz + pyrite ± purple fluorite vein in silicification-phyllic altered zone, Stage III quartz + pyrite + sphalerite + galena ± chalcopyrite ± green fluorite ± pink calcite in prophylitic altered zone and Stage IV quartz ± calcite vein in carbonatization zone based on cross-relationship. The Stage IIa and IIb veins characterize the main molybdenum mineralization stages. By microthermometry, CO2-bearing (C-), Water (WV- and WL-), and daughter minerals-bearing (S-) types of inclusions were recognized. The Stage I quartz contains C-type fluid inclusion assemblages (FIAs) with a salinity of 6.3 ± 1.4 wt% NaCl equiv., and a total homogenization temperature (Th, total) of 473 ± 3 °C. This suggests that the early fluids show characteristics of high temperature, CO2-rich, and moderate salinity, distinguishing them from those of Endako-type and Climax-type deposits. C-type and coexisting W-type FIAs from Stage IIa show similar salinity, ranging from 1.9 to 13.0 wt% NaCl equiv. and 1.9 to 14.1 wt% NaCl equiv., with Th, total of 349–376 °C and 327–392 °C, respectively. Moreover, C-type FIAs homogenize to distinct phases and also show similar homogenization temperatures, indicating fluid immiscibility. The FIAs in Stage IIb show an average salinity of 8.3 ± 7.4 wt% NaCl equiv. and a Th, total of 302 ± 14 °C. WL-type and WV-type FIAs coexist, with similar temperatures varying from 308 to 310 °C during this stage, indicating significant fluid boiling. These observations indicate that the decrease in temperature, fluid immiscibility, and decompression boiling collectively led to the precipitation of molybdenite. Trapping pressures are estimated to be 82–231 MPa for Stage IIa and 43–115 MPa for Stage IIb, corresponding to ore-forming depths of approximately 8.4 km and 4.3 km, respectively. Additionally, the He-Ar isotopes obtained from pyrite indicate a clear mixing trend of crustal fluids with mantle fluids at Stage IIb, with mantle-derived fluid components increasing during Stage III. This coincides with the tectonic shift from regional compression to extension, leading to the formation of many Dabie-type Mo deposits, alongside crustal thinning and the upwelling of asthenospheric mantle materials. Futhermore, Pb isotopes from the ore, ore-hosted gneiss, and ore-causative granitoids demonstrate that the Taihua Supergroup gneiss supplied ore-forming materials, suggesting a crustal origin for the Leimengou Mo deposit.

Study of phase equilibrium of refractory high-entropy alloys using the atomic size difference concept for turbine blade applications

Abstract In the pursuit of advancing turbine blade materials, refractory high-entropy alloys (RHEAs) have emerged as promising candidates, offering superior performance at elevated temperatures compared to conventional superalloys. With the plateauing of melting temperatures in Ni-based superalloys, the demand for innovative material systems capable of substantial performance enhancements in turbines has increased. The expansive compositional space of high-entropy alloys (HEAs) presents a rich yet underexplored realm, particularly concerning the intricate phase equilibria pivotal for alloy stability at high temperatures. This research purpose is to elucidate the phase formation dynamics within the W–Re–Ni–Co–Mo HEA system across varying atomic percentages of each constituent element. Employing two-dimensional mapping methodology for correlating atomic size difference and enthalpy mix parameters, enabling the differentiation between intermetallic (IM) phase and single-phase formations in the non-equimolar W–Re–Ni–Co–Mo system across numerous atomic percentages of each element. Major findings indicate distinct phase formations based on elemental compositions, with elevated nickel and rhenium percentages favouring single-phase solid solution (SPSS) structures, while diminished concentrations yield alternative configurations such as (IM + SPSS). Similarly, variations in tungsten and molybdenum concentrations influence phase stability. The ability to assess phases for diverse atomic percentages of elements in the W–Re–Ni–Co–Mo system will facilitate to analyse HEA systems for high-temperature turbine blades.

Age and petrogenesis of ore-bearing porphyry from the Houyu Mo-polymetallic deposit, central North China Craton

Porphyry-related molybdenum deposits formed within the plate's interior are unique, yet the understanding of the magmatic hydrothermal Mo system remains limited. Houyu is a typical porphyry-related Mo-polymetallic deposit situated in the inner region of the North China Craton (NCC). The ore bodies are found in Archean biotite plagioclase gneiss and diorite, followed by Early Cretaceous quartz porphyry, granite porphyry, and brecciated porphyry. Zircon U-Pb dating reveals that the biotite plagioclase gneiss, quartz porphyry, and granite porphyry were formed at 2499.2 ± 7.8 Ma, 135.19 ± 0.67 Ma, and 137.65 ± 0.84 Ma, respectively. Molybdenite Re-Os dating indicates a mean age of 134.94 ± 0.76 Ma and an isochron age of 134.7 ± 1.5 Ma, linking the Mo-polymetallic mineralization closely to the Early Cretaceous porphyry. The Houyu Cretaceous porphyry exhibits enrichment in light rare earth elements (LREEs), depletion in heavy rare earth elements (HREEs), and distinct positive Eu anomalies. Additionally, they are enriched in fluid-mobile large-ion-lithophile elements (LILEs) and significantly depleted in high-field-strength elements (HFSEs). These geochemical attributes suggest that the Cretaceous porphyry belongs to I-type adakitic granites. All samples exhibit consistently negative εNd(t) values ranging from −15.76 to −14.87 and εHf(t) values between −20.69 and −14.78, along with restricted 206Pb/204Pb (16.557–16.663), 207Pb/204Pb (15.262–15.300), and 208Pb/204Pb (36.601–36.747) ratios, indicating that they were derived from an ancient thickened lower continental crust (LCC). The Cretaceous magmatism and mineralization of the Houyu Mo-polymetallic deposit could be closely linked to the lithospheric thinning and destruction of the NCC triggered by the Paleo-Pacific or Izanagi Plate.

Theoretical study of transition metal subphthalocyanine molecules (TM@C24H12N6) as highly active electrocatalysts for the nitrogen reduction to ammonia

In this manuscript, we design a class of transition metal subphthalocyanine molecules as electrocatalysts for NRR. The results indicate that the Nb, Mo, and Tc systems can effectively absorb and activate a N2 molecule and reduce onset potentials (−0.50, −0.43, and −0.65 V, respectively). Among them, the Tc@C24H12N6 molecule has exceptionally high selectivity for NRR with the Faraday efficiency (FE) of ∼ 99.9 %. Therefore, the good stability, outstanding adsorption and activation properties of N2, very low onset potential, and high selectivity of Tc@C24H12N6 indicate it possesses promising catalytic activity for NRR among the investigated catalysts.

Phase equilibria in the Al–Fe–Mo system

This paper presents the results of our comprehensive study of phase equilibria in the Al–Fe–Mo system using DTA, X-ray diffraction, SEM and electron probe microanalysis. The liquidus and solidus projections were constructed. It is shown that the ternary compound Al8FeMo3 (τ) melts congruently at >1500 °C and has a homogeneity range from 2 to 9 at.% Fe and from 23.5 to 25 at.% Mo. Isostructural phases (Mo), (αFe) and AlMo (W-type structure, cI2-Im-3m) at solidus temperatures form a continuous solid solution (αFe,Mo,AlMo). Unlike the AlMo binary phase, which is not retained by quenching, the ternary (αFe,Mo,AlMo) phase is easily quenched due to its lower decomposition temperature. Among the binary based phases, the Al8Fe5 (ε) phase has the widest homogeneity region, which extends up to 24 at.% Mo at solidus temperatures. It is shown that the addition of Mo stabilizes the Al8Fe5 (ε) phase, and the temperature of its formation in the ternary system increases to 1331 °C in contrast to 1234 °C in the binary. Moreover, according to XRD data, the Al8Fe5 (ε) phase in the ternary system has a rhombohedral structure of the Al8Cr5-type (hR78-R-3m), rather than cubic Cu5Zn8-type structure (cI52-I-43m), like the binary one. A new binary compound Al45Mo7 was identified for the first time. Its crystal structure is established as monoclinic Al45V7-type (mS104-C2/m) with the lattice parameters a = 20.534, b = 7.561, c = 10.910 Å, β = 107.33. It was shown to form by peritectic reaction L + Al5Mo ⇄ Al45Mo7 at ∼800 °C. Iron additions stabilize the Al4Mo phase, which in the binary system is stable above 942 °C.

Design and Characterization of a Novel NiAl–(Cr,Mo) Eutectic Alloy

To enhance the mechanical properties of NiAl–(Cr,Mo) in situ composites for high‐temperature structural use, achieving a regular eutectic microstructure is crucial. A novel alloy with a composition of Ni30.6Al36Cr31.4Mo2 is developed that exhibits a significantly reduced solidification interval compared to well‐studied alloys such as Ni33Al33Cr28Mo6. This advancement results from using the in‐house developed alloy design tool PyMultOpt and Calculation of Phase Diagrams analysis to minimize the solidification interval. The refined alloy demonstrates a theoretical solidification interval of 0 K. These results are verified with differential scanning calorimetry measurements at different heating rates for the new alloy and compared with the established alloy Ni33Al33Cr28Mo6. The small solidification interval leads to a uniform eutectic microstructure consisting of a (Cr,Mo) phase embedded in the NiAl matrix without primary NiAl dendrites present. This indicates that deviating from the stoichiometric NiAl composition results in a significantly lower solidification interval and thus in an actual eutectic composition of the NiAl–(Cr,Mo) system.

Preparation of Z-type Cu2SnS3/g-C3N4 heterojunction material and its synergistic photocatalytic performance with H2O2

Due to poor visible light responsiveness and easy recombination of photo generated carriers, the photocatalytic performance of a single g-C3N4 is limited. This article presents a Z-type Cu2SnS3/g-C3N4 (CTS/CN) heterojunction photocatalyst prepared by in-situ growth of CTS on the surface of g-C3N4 using a simple solvothermal method. Through SEM results, it can be seen that as the content of g-C3N4 increases, the nanosheet gaps of flower shaped microspheres on the surface of CTS/CN increase and the size becomes thinner. The UV–vis DRS experiment showed that the introduction of CTS increased the visible light absorption range of CTS/CN composite and improved its visible light absorption ability.Under the synergistic effect of H2O2, the photocatalytic degradation efficiency of CTS/70% CN towards MO reached 99% at 50 minutes，At the same time, the degradation rate constants k of methylene blue (MB), ciprofloxacin (CIP) and levofloxacin (LEV) reached 0.06289 min−1, 0.02132 min−1 and 0.02787 min−1 respectively at 100 min.In the synergistic MO system of H2O2 for photocatalytic degradation, free radical capture experiments showed that the main active species were h+and • OH. Combined with the band structure of Cu2SnS3 and g-C3N4, a Z-type photocatalytic mechanism was proposed. Under visible light, H2O2 rapidly captured the photo generated electrons of CTS/CN, promoting the transport of photo generated carriers. This study provides theoretical guidance for the design and construction of Z-type heterojunctions with superior visible light driven photocatalytic performance.

Corrosion resistance investigation of the Ti–Al–Mo system supported by CALPHAD approach and key experiments

The corrosion resistance of Ti–Al–Mo alloys in seawater were investigated by thermodynamic calculations and electrochemical tests. Four as-cast alloys were designed based on thermodynamic calculations. The calculated results were verified by experimental determination. The Gibbs energy and electrochemical experiment results showed Ti55Al40Mo5 alloy has the most positive Gibbs energy and the best corrosion resistance. The bcc(Ti) phase has best corrosion resistance among AlTi, AlTi3 and bcc(Ti). The present work further proves the important role of phase diagram calculation in alloy design, and thermodynamic database provides important theoretical support for efficient development of new alloys.

Electrodeposited alloy electrodes in the Co–W–Mo system as highly efficient catalysts for hydrogen production from alkaline water electrolysis

In the presented paper the non-precious electrode materials containing Co, Mo, and W demonstrating high catalytic activity towards hydrogen evolution reaction were characterized. The studied alloy electrodes were electrodeposited from electrolytes with a simple composition, containing CoSO4, Na2WO4, Na2MoO4, and Na3C6H5O7. The structure, surface morphology, and composition of the prepared deposits were analyzed using scanning microscopy, X-ray diffraction, and transmission electron microscopy techniques. Cathodic polarization and electrochemical impedance spectroscopy were applied to assess the electrocatalytic activity and elucidate the HER mechanism in 1 M KOH solution. The nanocrystalline structure, fine grain size, and presence of microcracks on the surface of the studied alloys contributed to their notably high electrochemically active surface area (ECSA) (65.7e2, 11.7e4, and 99.7e3 cm2 for the Co–W, Co–Mo, and Co–W–Mo, respectively), a crucial factor driving their superior catalytic activity. The intrinsic catalytic activity evaluated at the overpotential of 150 mV was 9.2, 3.3, 0.78 and 1.4 μA cm-2 for the Co, Co–W, Co–Mo and Co–W–Mo electrodes, respectively. This indicates that the superior electrocatalytic characteristics observed for the alloy coatings, compared to Co resulted from the substantial increase in their ECSA. Among the investigated electrodes, the ternary Co–W–Mo alloy was characterized by the highest electrocatalytic performance confirmed by the lowest overpotential (42 mV) required to attain a current density of 10 mA cm−2.

Protracted metallogenic and magmatic evolution of the Kirazlı epithermal Au-Ag and porphyry Cu deposits, Biga Peninsula, NW Turkey: evidence from zircon U-Pb, muscovite 40Ar/39Ar, and molybdenite Re-Os geochronology

The Kirazlı deposit is located at the center of the Biga Peninsula metallogenic province, in a geological setting characterized by an extensional tectonic environment. A NNW-SSE trending high-sulfidation (HS) orebody with a total reserve of 33.86 Mt @ 0.69 g/t Au and 9.42 g/t Ag lies beneath the Kirazlı Main zone. A porphyry Cu orebody hosted by Eocene intrusive and volcanic rocks has been intersected by drilling within its vicinity. The HS epithermal deposit is hosted by a partly silicified and brecciated Oligocene volcanic and volcaniclastic sequence consisting mainly of basaltic andesite lava flow and lithic/crystal tuff. Lithogeochemistry and zircon U-Pb radiometric ages allow us to distinguish three distinct high-K calc-alkaline magmatic events at ca. 41, 38, and 32 Ma, sourced by metasomatized mantle melts, which have interacted with the crust during their ascent. Porphyry Cu mineralization took place at 36.7 ± 0.4 Ma (muscovite 40Ar/39Ar age) with subsequent re-opening and base metal deposition. Crosscutting quartz-pyrite-molybdenite veins were emplaced at 33.6 ± 0.2 Ma (molybdenite Re-Os age), and followed by the HS epithermal Au-Ag event at ca. 31 Ma, based on a previous study. Our radiometric data indicate that the Kirazlı deposit has recorded a long-lasting Cenozoic magmatic and metallogenic evolution during about 10 Myr. Our study demonstrates that successive, independent, and overprinting, but genetically unrelated, HS epithermal precious metal, hydrothermal Mo, base metal, and porphyry Cu systems have been active at the same location during protracted extensional tectonics of the Biga Peninsula.

The Ahadawa deposit—A newly discovered porphyry Cu–Mo system in the North Qaidam, Northern Qinghai-Tibet Plateau, NW China

Ongoing exploration in the North Qaidam, Northern Qinghai-Tibet Plateau, NW China, has led to the identification of a porphyry Cu-Mo system centered on Ahadawa. In this study, we conducted a detailed geochronological and geochemical study on porphyritic monzogranite from the Ahadawa deposit, which hosts the Cu-Mo mineralization. The weighted mean zircon U-Pb ages for three mineralized porphyritic monzogranite samples from different sites range from 218.8 ± 1.2 Ma (MSWD = 1.5) to 224.7 ± 1.6 Ma (MSWD = 1.8), and finally to 233.1 ± 0.9 Ma (MSWD = 1.4, n = 23). These results, combined with antecrystic grains as old as ∼ 245.7 Ma, collectively indicate more than 25 Ma multi-stage magmatic emplacement activity in the Ahadawa deposit. Corresponding to complex magma episodes, six studied molybdenite samples yielded variable Re-Os model ages ranging from 436.7 ± 6.6 to 232.6 ± 1.2 Ma, with the three youngest dates constraining a weighted mean Re-Os age of 234.0 ± 6.8 Ma. The 234 Ma mineralization age is consistent with the observed Late Triassic magmatism, whereas the Re-Os model ages of 436.7 to 245.7 Ma, if they remain robust through future investigation, may highlight a long-lived hydrothermal activity in the Ahadawa deposit. Whole-rock and zircon compositions indicate that the Late Triassic porphyries occurring at the surface display distinct geochemical features, with the early porphyritic monzogranite of 233.1 Ma characterized by much higher whole-rock Sr/Y, and zircon Eu/Eu* and Ce/Ce* than the younger (218.8 Ma and 224.7 Ma, respectively) porphyritic monzogranite. This suggests that the Late Triassic magmas were initially characterized by high water content and high oxidation state and the differences between the old and two younger groups might be related to plagioclase-dominated fractionation. The finding of the Ahadawa porphyry system highlights the need for ongoing exploration (especially in poorly studied remote areas) and systematically geochronological and geochemical studies to constrain the temporal and spatial evolution of mineralized episodes within a complex, protracted magmatic history.

The geochronology, geochemistry, and petrogenesis of the Leimengou porphyries, Qinling Orogen: A case study of intrusions associated with a Dabie-type porphyry Mo deposit

The Leimengou giant Mo deposit is a porphyry system in the northeastern Qinling Orogen along the southern margin of the North China Craton, comprising orebodies hosted mainly in a multiphase porphyritic granitic to monzonitic pluton emplaced in the Taihua Supergroup. Zircons from the syn-ore porphyritic monzogranite (PMG) and the porphyritic K-feldspar granite (PKG) yielded U − Pb ages of 131.3 ± 1.0 Ma and 130.6 ± 0.9 Ma, respectively. The post-ore, quartz monzonite porphyry (QMP), has a weighted mean 206Pb/238U age of 124.6 ± 1.0 Ma (n = 14, 1σ, MSWD = 0.13). These ages constrain the Leimengou porphyry system to have formed between 132 and 124 Ma. The PMG and PKG have similar geochemical characteristics, i.e., high-K calc-alkaline affinity, negative εHf(t) values of − 25.1 to − 22.0 and − 25.1 to − 19.2, and TDM2 ages of 2.77–2.57 Ga and 2.76–2.40 Ga, respectively. The PKG has lower concentrations for Sr, Ba, and negative anomalies of δEu, and also has higher total REE values compared to the PMG. These anomalies are interpreted to reflect fractional crystallization involving plagioclase and biotite. The characteristics of the PKG support its derivation from an evolved magma, which likely facilitated the enrichment of Mo. Additionally, the Hf isotope data suggest that the Leimengou porphyry system had a composite source, with inputs from the North Qinling Accretion Belt, the North China Craton, and the mantle. Compared to the syn-ore PMG, the post-ore QMP exhibits lower (La/Yb)N ratios of 20.5–22.8, higher zircon εHf(t) values of − 19.7 to − 9.0, and younger TDM2 ages of 2.42–1.75 Ga. This suggests that the Leimengou porphyry Mo system formed during thinning of an overthickened orogenic crust during the tectonic transition from collisional compression to post-collisional extension. The productive intrusions at Leimengou and other porphyry Mo deposits of Dabie-type have average Nb/Zr ratios that are typically below 1. Moreover, the Rb/Sr ratios range from 0.1 to 1, further distinguishing these intrusions from the intrusions associated with Climax- and Endako-type Mo deposits.

Diffusivities and atomic mobilities in bcc Ti–V–Mo alloys

In pursuit of a comprehensive exploration into the diffusion kinetics of bcc Ti–V–Mo alloys, sixteen sets of diffusion couples were prepared within the bcc phase of Ti–V–Mo alloys. These diffusion couples were subjected to annealing at 1373 K and 1473 K. Composition profiles were obtained by means of the electron probe micro-analysis technique (EPMA). The calculation of diffusivities in bcc Ti–V–Mo alloys was performed using the Whittle-Green and Hall methods. Based on available thermodynamic descriptions, the atomic mobility parameters of the bcc Ti–V–Mo system were assessed by using the DICTRA module of the Thermo-Calc software. A comparison is made between the simulated composition-distance curve and the diffusion path with the experimental values, revealing a significant level of concordance.

Ti-Al-based alloys with Mo: high-temperature phase equilibria and microstructures in the ternary system

ABSTRACT Molybdenum is one of the major alloying elements in TiAl-based alloys for high-temperature structural applications developed over the last decades. This is due to its stabilising effect on the (βTi) phase at high-temperatures, which crucially improves the hot-workability of such alloys. For further alloy development, an exact knowledge of the phase equilibria in the Ti–Al–Mo system is essential. However, there are still uncertainties and inconsistencies related to the ternary phase diagram. In this study, a series of ternary alloys was produced and heat-treated between 700 and 1300 °C. Composition, structure, and thermal stability of the phases were analysed and the resulting phase equilibria were established by applying a combination of scanning electron microscopy (SEM), electron probe microanalysis (EPMA), differential scanning calorimetry (DSC), and high-energy X-ray diffraction (HEXRD). From these results, a series of partial isothermal sections is obtained illustrating the phase equilibria in the Ti-rich part of the Ti–Al–Mo system.

Improvement of Fe(Ⅲ)/percarbonate system by molybdenum powder and tripolyphosphate: Co-catalytic performance, low oxidant consumption, pH-dependent mechanism

The homogeneous sodium percarbonate (SPC) systems are limited by narrow pH range, ineffective consumption of oxidant, and weak reusability of catalyst. Herein, molybdenum (Mo) powder and sodium tripolyphosphate (STPP) were selected to overcome these challenges. Sulfamethoxazole (SMX), as a model contaminant, was almost completely degraded in 60 min with higher removal rate (0.1367 min−1) than the Mo or STPP-absent system. In addition, Mo/STPP-Fe(Ⅲ)/SPC system was cost-effective in terms of oxidant consumption, requiring only 0.2 mM SPC. About activation mechanism, the main active species for SMX degradation was pH-dependent, with hydroxyl radical (·OH) as the dominant active species at pHi = 7 and ·OH, carbonate radical (CO3·-), and superoxide radical (O2·-) derived from a series of chain reaction at pHi = 10, respectively. Due to the generation of various electrophilic free radical, the system exhibited excellent performance towards electron-rich pollutants under a wide pH range. Furthermore, Mo exhibited excellent stability and reusability. SMX was degraded through hydroxylation, N-S cleavage, amino and sulfanilamide oxidation into intermediates whose toxicities were evaluated by Toxicity Estimation Software Tool (T.E.S.T.) software. This work provided new insights to Fe/SPC system towards high-efficiency and low consumption treatment of practical application.

Chemistry and boron isotope composition of tourmaline as a robust tool to characterize the origin of porphyry molybdenum systems: The case of Donggebi deposit in East Tianshan, China

Tourmaline is a chemically and mechanically stable mineral that commonly occurs in hydrothermal mineral systems, and has been used to trace the mineralization processes of many genetic types of ore deposits. Here we apply tourmaline chemistry and isotopic composition to trace the genesis of a porphyry Mo system for the first time. Tourmaline is widespread in the Donggebi Mo deposit in East Tianshan, NW China, where it occurs in five distinct associations: type PG disseminated in the porphyritic granite, TS as hydrothermal tourmalite in the country rocks (strata), V1 in quartz-molybdenite vein, V2 in quartz-polymetallic sulfide vein, and V3 quartz-calcite-fluorite vein. All the tourmaline types belong to the alkali group, with the V3 being schorl and the other types being dravite and schorl. The PG-type tourmalines partly inherit the features of the porphyritic granite, and are rich in F, Na, Al and Sc, and poor in Fe, Mg, Ca, Sr, Ba, Pb, V and Mo compared to the other types. They have low Fe3+ concentrations and low Fe3+/(Fe3++Fe2+) ratios, suggesting a reducing fluid system. They also display weaker Eu-depletion (with an average (Eu/Eu*)N value of 0.96) than the porphyritic granite, and are considered to be the products of interaction of the reducing fluids and the granites. The average (Eu/Eu*)N values of tourmalines decrease from 6.66 of type V1, 5.65 of type V2, to 4.80 of type V3, indicating that the fluids became progressively less reducing along with sulfide precipitation. The δ11B values of the tourmalines range between −15.9 ‰ and −12.5 ‰, resembling those of S-type granites or clastic sediment-sourced hydrothermal fluids. The tourmaline grains in our study do not display any remarkable δ11B variation from the cores to rims, indicating that the δ11B values of the fluids and their source were relatively constant.

Atomic structure and electronic properties of Ce + O films co-adsorbed on Mo(112)

The atomic structure, stoichiometry and electron work function of Ce + O films co-adsorbed on Mo(112) were studied by low-energy electron diffraction (LEED), Auger electron spectroscopy (AES) and contact potential difference (CPD) methods. The films with a significant predominance of one major species show the structure characteristic of the main component, which remains stable up to 15−50% of the minor species content. We report the c(4 × 4) and c(2 × 6) superstructures for Ce + O films with single layer Ce coverage as well as c(4 × 6) and (2 × 2) for double layer Ce coverage. They are exclusively specific to the (Ce + O)/Mo(112) system and have not been previously observed neither for cerium oxides nor pure cerium/pure oxygen adfilms. No noticeable electron work function change was detected due to oxygen addition to the Ce/Mo(112) films. Both oxygen-enriched and oxygen-depleted (Ce + O) films show similar typical electropositive properties.

Experimental testing of radial-shear rolling to obtain a deformed alloy of the Co – Cr – Mo system

Experimental testing of radial-shear rolling to obtain a deformed alloy of the Co – Cr – Mo system