Anisotropic atomic mobilities of hcp Zr(O) solid solution and their application in description of early-stage oxidation process of pure Zr

2021 ◽  
pp. 109445
Author(s):  
Qiang Tang ◽  
Sa Ma ◽  
Fangzhou Xing ◽  
Lijun Zhang
Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1686 ◽  
Author(s):  
Carolin Heim ◽  
Mohamad Rajab ◽  
Giorgia Greco ◽  
Sylvia Grosse ◽  
Jörg E. Drewes ◽  
...  

The focus of this study was to investigate the efficacy of applying boron-doped diamond (BDD) electrodes in an electrochemical advanced oxidation process, for the removal of the target compound diclofenac (DCF) in different water matrices. The reduction of DCF, and at the same time the formation of transformation products (TPs) and inorganic by-products, was investigated as a function of electrode settings and the duration of treatment. Kinetic assessments of DCF and possible TPs derived from data from the literature were performed, based on a serial chromatographic separation with reversed-phase liquid chromatographyfollowed by hydophilic interaction liquid chromatography (RPLC-HILIC system) coupled to ESI-TOF mass spectrometry. The application of the BDD electrode resulted in the complete removal of DCF in deionized water, drinking water and wastewater effluents spiked with DCF. As a function of the applied current density, a variety of TPs appeared, including early stage products, structures after ring opening and highly oxidized small molecules. Both the complexity of the water matrix and the electrode settings had a noticeable influence on the treatment process’s efficacy. In order to achieve effective removal of the target compound under economic conditions, and at the same time minimize by-product formation, it is recommended to operate the electrode at a moderate current density and reduce the extent of the treatment.


Solid Earth ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 1-21 ◽  
Author(s):  
Ariadni A. Georgatou ◽  
Massimo Chiaradia

Abstract. We investigate the occurrence and chemistry of magmatic sulfides and their chalcophile metal cargo behaviour during the evolution of compositionally different magmas from diverse geodynamic settings both in mineralised and barren systems. The investigated areas are the following: (a) the Miocene Konya magmatic province (hosting the Doğanbey Cu–Mo porphyry and Inlice Au epithermal deposits, representing post-subduction) and (b) the Miocene Usak basin (Elmadag, Itecektepe, and Beydagi volcanoes, the latter associated with the Kişladağ Au porphyry in western Turkey, representing post-subduction). For comparison we also investigate (c) the barren intraplate Plio-Quaternary Kula volcanic field west of Usak. Finally, we discuss and compare all the above areas with the already studied (d) Quaternary Ecuadorian volcanic arc (host to the Miocene Llurimagua Cu–Mo and Cascabel Cu–Au porphyry deposits, representing subduction). The volcanism of the newly studied areas ranges from basalts to andesites–dacites and from high-K calc-alkaline to shoshonitic series. Multiphase magmatic sulfides occur in different amounts in rocks of all investigated areas, and, based on textural and compositional differences, they can be classified into different types according to their crystallisation at different stages of magma evolution (early versus late saturation). Our results suggest that independently of the magma composition, geodynamic setting, and association with an ore deposit, sulfide saturation occurred in all investigated magmatic systems. Those systems present similar initial metal contents of the magmas. However, not all studied areas present all sulfide types, and the sulfide composition depends on the nature of the host mineral. A decrease in the sulfide Ni∕Cu (a proxy for the monosulfide solid solution (mss) to intermediate solid solution (iss) ratio) is noted with magmatic evolution. At an early stage, Ni-richer, Cu-poorer sulfides are hosted by early crystallising minerals, e.g. olivine–pyroxene, whereas, at a later stage, Cu-rich sulfides are hosted by magnetite. The most common sulfide type in the early saturation stage is composed of a Cu-poor, Ni-rich (pyrrhotite mss) phase and one to two Cu-rich (cubanite, chalcopyrite iss) phases, making up ∼84 and ∼16 area % of the sulfide, respectively. Sulfides resulting from the late stage, consisting of Cu-rich phases (chalcopyrite, bornite, digenite iss), are hosted exclusively by magnetite and are found only in evolved rocks (andesites and dacites) of magmatic provinces associated with porphyry Cu (Konya and Ecuador) and porphyry Au (Beydagi) deposits.


2019 ◽  
Author(s):  
Ariadni Georgatou ◽  
Massimo Chiaradia

Abstract. We investigate in both mineralised and barren systems the occurrence and chemistry of magmatic sulphides and their chalcophile metal cargo behaviour during evolution of compositionally different magmas in diverse geodynamic settings. The investigated areas are: (a) the Miocene Konya magmatic province (hosting the Doganbey Cu-Mo and Inlice Au-epithermal deposits) (Post-Subduction) and (b) the Miocene Usak basin (Elmadag, Itecektepe and Beydagi volcanoes, the latter associated with the Kisladag Au porphyry) in Western Turkey (Post-Subduction). For comparison we also investigate (c) the barren Plio-Quaternary Kula volcanic field, west of Usak (Intraplate) and finally we discuss and compare all the above areas with the already studied (d) Quaternary Ecuadorian volcanic arc (host to the Miocene Llurimagua Cu-Mo and Cascabel Cu-Au porphyry deposits) (Subduction). The volcanism of the studied areas displays a wide range of SiO2 spanning from basalts to andesites/dacites and from high K-calc-alkaline to shoshonitic series. Multiphase magmatic sulphides occur in different amounts in all investigated areas and based on textural and compositional differences, they can be classified in different types, which crystallised at different times (early versus late saturation). A decrease in the sulphide Ni/Cu (proxy for mss-monosulphide solid solution/iss-intermediate solid solution) ratio is noted with magmatic evolution. Starting with an early stage, saturating Ni-richer/Cu-poorer sulphides hosted by early crystallising minerals e.g. olivine/pyroxene, leading up to a later stage, producing Cu-richer sulphides hosted by magnetite. The most common sulphide type resulting from an early saturating stage is composed of a Cu-poor/Ni-rich (pyrrhotite/mss) and one/two Cu-rich (cubanite, chalcopyrite/iss) phases making up 84 and 16 area % of the sulphide, respectively. Our results suggest that independently of the magma composition, geodynamic setting and whether or not the system has generated an ore deposit on the surface, sulphide saturation occurred in variable degrees in all studied areas and magmatic systems and is characterised by a similar initial metal content of the magmas. However not all studied areas present all sulphide types and the sulphide composition is dependent on the nature of the host mineral. In particular sulphides, resulting from the late stage, consisting of Cu-rich phases (chalcopyrite ,bornite, digenite/iss) are hosted exclusively by magnetite and are found only in magmatic provinces associated with porphyry Cu (Konya and Ecuador) and porphyry Au (Beydagi) deposits.


2010 ◽  
Vol 645-648 ◽  
pp. 813-816 ◽  
Author(s):  
Keiko Kouda ◽  
Yasuto Hijikata ◽  
Hiroyuki Yaguchi ◽  
Sadafumi Yoshida

We have investigated the oxidation process of SiC (000-1) C-face at low oxygen partial pressures using an in-situ spectroscopic ellipsometry. The oxide growth rate decreased steeply at the early stage of oxidation and then slowly decreased with increasing oxide thickness. The initial oxide growth rate was almost proportional to the oxygen partial pressure for both the polar directions. This result suggests that the initial interfacial reaction rate is constant regardless of the concentration of oxidants reaching the interface.


2011 ◽  
Vol 172-174 ◽  
pp. 111-116 ◽  
Author(s):  
Francisca García Caballero ◽  
Michael K. Miller ◽  
Carlos García-Mateo

The amount of carbon in solid solution in bainitic ferrite at the early stage of transformation has been directly determined by atom probe tomography at 200 °C, taking advantage of the extremely slow transformation kinetics of a novel nanocrystalline steel. Results demonstrated that the original bainitic ferrite retains much of the carbon content of the parent austenite providing strong evidence that bainite transformation is essentially displacive in nature.


Author(s):  
Johsei Nagakawa ◽  
A. Sato ◽  
M. Meshii

Solid solution softening and the orientation dependence of yield stress can be regarded as the two most important phenomena characterizing the low temperature plastic deformation of b.c.c. metals. Recently, the orientation dependence of solid solution softening was reported in electron irradiated pure iron in which self-interstitial atoms simulate the solid solution effect. Single crystals oriented for the hard (112) slip showed the largest softening effect and became the softest crystals after irradiation (Fig. 1). Also, the shape of the stress-strain curve for the irradiation-softened crystal suggests that the irradiation may have influenced the dislocation structure at an early stage of deformation. Specimens oriented for the soft (211) slip showed hardly any effect. In this study, the dislocation structure was investigated to determine the mechanism responsible for the softening effect and the orientation dependence.


2016 ◽  
Vol 852 ◽  
pp. 9-13 ◽  
Author(s):  
Jin Lou ◽  
Cheng Xiang Ruan

0Cr18Ni10Ti stainless steel was coated by hot-dipping in a molten aluminum bath, and then diffusing annealing at 950 °C for 2h. Aluminized steel was composed of three layers: outer layer FeAl2 phase and FeAl phase, intermediate layer FeAl phase, and inner solid solution with Al. The cyclic oxidation resistance of aluminized steel with outer layer and aluminized steel without outer layer were tested at 900 °C for 24 cycles using resistance furnace. Morphology, and phase composition, element distribution of the oxide scale were characterized by XRD, SEM and EDS. The oxidation result showed that weight loss on aluminized steel with outer layer was observed at early stage, weigh gain was obtained slowly at later stage, while the weight gain was observed on aluminized steel without outer layer during 24 cycles. The weigh gain of both samples was about 0.7mg/cm2 after 24 cycles. It was found that cracks on aluminized steel with outer layer were more than aluminized steel without outer layer due to thicker FeAl layer on aluminized steel with outer layer. A thin NiAl phase layer was found between FeAl layer and inner solid solution layer on both samples decrease the depletion rate of aluminum.


2012 ◽  
Vol 476-478 ◽  
pp. 1318-1321
Author(s):  
Qi Zhi Cao ◽  
Jing Zhang

Nanostructured Fe25Al57.5Ni17.5intermetallics was prepared directly by mechanical alloying (MA) in a high-energy planetary ball-mill. The phase transformations and structural changes occurring in the studied material during mechanical alloying were investigated by X-ray diffraction (XRD). Thermal behavior of the milled powders was examined by differential thermal analysis (DTA). Disordered Al(Fe,Ni) solid solution was formed at the early stage. After 50 h of milling, Al(Fe,Ni) solid solution transformed into Al3Ni2,AlFe3,AlFe0.23Ni0.77 phase. The power annealed at temperature 500 results in forming of intermetallics AlFe3 and FeNi3 after 5h milling. The nanocrystalline intermetallic compound was obtained after 500h milling.


Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 247
Author(s):  
Jianping Jin ◽  
Wentao Zhou ◽  
Yongsheng Sun ◽  
Yuexin Han ◽  
Yanjun Li

It is particularly significant to investigate the reduction behavior and existing form of phosphorus in metal and slag phase during coal-based reduction for the efficient development and utilization of high-phosphorus oolitic hematite. The reduction behavior of phosphorus minerals and their existing form in the metal and slag phase during the coal-based reduction of high phosphorus oolitic hematite were systematically investigated using HSC software simulation, thermodynamic calculation, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectrometry (EDS). The results show that after Fe2O3 was reduced to metal iron, the reduction of apatite was promoted by providing the most inclined enrichment site of phosphorus (metallographic phase). Phosphorus existed mainly in two forms in the metal phase—one was in the form of Fe3P compound at the boundary of the metal phase, and the other was in the form of solid solution in the metal iron. There were two forms of phosphorus in the slag phase—one was incompletely reacted apatite, and the other was formed as CaO–SiO2–P2O5 solid solution. In the early stage of coal-based reduction, phosphorus in the slag phase mainly existed in the form of apatite, while in the later stage, it mainly existed in the form of CaO–SiO2–P2O5 solid solution.


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