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1.
In the present work, high temperature oxidation of HP40 alloy was carried out at 1050 °C under H2–H2O and air atmospheres; the influence of atmosphere on surface morphology and composition was studied. Octahedral crystals with considerable spalled regions are present on the surface of alloy oxidized under air, the oxide scale composes of MnCr2O4, Cr2O3 and (Fe, Ni)Cr2O4 and spalled regions exhibit base alloy and SiO2‐rich regions. The surface of alloy oxidized under H2–H2O is fully covered by small granular crystals and blade‐type structures without spallation, and the oxide scale composes of MnCr2O4 and Cr2O3. Moreover, X‐ray photoelectron spectroscopy analysis shows considerable difference in chemical valence states of Mn, Cr and O elements on both alloy surfaces, and hydroxyl compounds exist on the alloy oxidized under H2–H2O atmosphere. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

2.
In this study, the initial oxidation behaviour of laser‐treated Al/NiCrAlY bond‐coat is investigated. Two approaches, (i) Al film sputtering on the surface of bond‐coat and (ii) laser treatment, have been taken to enhance the oxidation resistance of NiCrAlY bond‐coat. Experimental results showed that after laser treatment, the Al/NiCrAlY bond‐coat exhibited a columnar dendritic microstructure without cracks and voids. A dense and continuous α‐Al2O3/Cr2O3 multilayer was found to form on the bond‐coat surface. Results on the cyclic oxidation at 1200 °C (for time ≤ 204 h) revealed that the laser‐treated Al/NiCrAlY bond‐coat exhibited better oxidation resistance compared to as‐sprayed NiCrAlY, Al/NiCrAlY and laser‐remelted NiCrAlY bond‐coat. The formation of θ‐Al2O3, NiO, Cr2O3 and NiCr2O4 spinel oxides was observed to be suppressed due to the preformed α‐Al2O3 scale during initial oxidation on the surface of laser pre‐oxidized Al/NiCrAlY bond‐coat. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

3.
Contributions on Crystal Chemistry and Thermal Behaviour of Anhydrous Phosphates. XXXI. (Mg1–xCrx)2P2O7, CaCrP2O7, SrCrP2O7 and BaCrP2O7 – New Diphosphates of Divalent Chromium In the quasi‐binary systems A2P2O7/Cr2P2O7 (A = Mg, Ca, Sr, Ba) the solid solution (Mg1–xCrx)2P2O7 as well as the new compounds CaCrP2O7, SrCrP2O7, and BaCrP2O7 have been synthesized and characterized for the first time. In the whole experimental range (0.01 < x < 0.94; T = 950 °C) the solid solution (Mg1–xCrx)2P2O7 is isotypic to the pure phases β‐Mg2P2O7 and β‐Cr2P2O7; but no phase transition (β → α) to a low‐temperature modification, as in Mg2P2O7 and Cr2P2O7, was found. CaCrP2O7 ( A ), SrCrP2O7 ( B ), and BaCrP2O7 ( C ), phases without detectable homogenity range in the other quasi‐binary systems are not structurally related to each other, but are isotypic to the corresponding compounds containing cobalt. [( A ): P‐1, Z = 2, a = 6.312(2) Å, b = 6.499(2) Å, c = 6.916(2) Å, α = 83.12(3)°, β = 88.37(3)°, γ = 67.72(3)°, 3235 independent reflections, R1 = 0.041, wR2 = 0.112; ( C ): P‐1, Z = 2, a = 5.382(8) Å, b = 7.271(8) Å, c = 7.589(4) Å, α = 103.33(7)°, β = 89.91(9)°, γ = 93.6(1)°, 1571 independent reflections, R1 = 0.085, wR2 = 0.31]. We have reported earlier details on SrCrP2O7. The coordination of Cr2+ by oxygen is distorted octahedral in ( A) , while in the structures of ( B) and ( C) square‐pyramidal environment is found. The results of UV/VIS‐spectroscopic and magnetic measurements as well as IR‐spectra of the diphosphates are reported.  相似文献   

4.
Ni‐based superalloys with niobium (Nb) or/and yttrium (Y) were prepared by vacuum melting. The oxidation kinetics of these alloys was studied by thermogravimetry at 800 °C for 100 h in static air. Morphology of oxides was studied using SEM, and the composition was analyzed by X‐ray diffraction. Energy‐dispersive X‐ray spectrometer was employed to examine the linear element distribution of the cross section of the oxidation films. Results showed that the oxidation kinetics all followed a parabolic law at different stages. The oxide films were mainly comprised of Cr2O3, NiCr2O4, Al2O3 and TiO2. All the oxide films exhibited layered structure owing to different oxidation stages. With the addition of Nb or Y, the high‐temperature oxidation resistance of the superalloy was improved significantly and the surface morphology of the oxidation film was ameliorated. The comprehensive effect of Nb and Y was remarkable in improving the high‐temperature oxidation resistance of Ni‐based alloys. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

5.
A new coordination polymer (CP), namely, [Cd(HL)(4,4′‐bipy)] ( 1 ) (H3L = 4‐(5‐carboxy‐pyridine‐3‐yloxy)‐phthalic acid, 4,4′‐bipy = 4,4′‐bipyridine), was synthesized employing a V‐shaped asymmetric tricarboxylic acid ligand under hydrothermal condition. Single‐crystal X‐ray diffraction analysis indicates that compound 1 exhibits a novel three‐dimensional (3D) framework with (3, 5)‐connected (63)(69 · 8) topology. Meanwhile, it shows high selectivity and sensitivity for oxoanion pollutants CrO42–, Cr2O72–, and MnO4 anions in aqueous solutions with detection limits of 4.12 × 10–6 M, 1.75 × 10–6 M, and 6.47 × 10–7 M, respectively. The high selectivity and low detection limit indicate that the compound is promising functional luminescence probe for CrO42–, Cr2O72–, and MnO4. The mechanisms of the quenching effect and sensing properties were discussed in detail.  相似文献   

6.
Cr‐Mn‐O spinel coating was prepared on the surface of cobalt‐based superalloy GH605 via an in‐situ oxidation method in H2O‐H2 environment. The composition, morphology, and chemical value state of the oxide spinel coatings were investigated by SEM, EDS, XRD, Raman spectra, and XPS. It indicated that the morphology of coating varied with oxidation temperature, and granular surface appeared when oxidation temperature increased to 1100°C. The formed Cr‐Mn‐O spinel coating was composed of Cr2O3 and MnCr2O4, and the thickness increased significantly with oxidation temperature. In the coating, Cr element existed in the state of Cr3+ ions and Cr6+ ions, while Mn element only existed in the form of Mn2+ ions.  相似文献   

7.
Novel heterogeneous catalysts were prepared using immobilization of bis(2‐decylsulfanylethyl)amine–CrCl3 (Cr‐SNS‐D) on various supports, namely commercial TiO2, Al2O3 and magnetic Fe3O4@SiO2 nanoparticles, to yield solid catalysts denoted as support@Cr‐SNS‐D. The structure of the catalysts was confirmed on the basis of spectroscopic analyses, N2 adsorption–desorption and inductively coupled plasma (ICP) analysis. The surface areas of Al2O3@Cr‐SNS‐D, Fe3O4@SiO2@Cr‐SNS‐D and TiO2@Cr‐SNS‐D catalysts were determined to be 70, 23 and 41 m2 g?1, respectively. A decrease in surface area from that of the supports clearly establishes accurate immobilization of Cr‐SNS‐D catalyst on the surface of the parent carriers. The loading of Cr was determined to be 0.02, 0.16 and 0.11 mmol g?1 for Cr‐SNS‐D supported on TiO2, Al2O3 and Fe3O4@SiO2, respectively, using ICP analysis. After preparation and full characterization of the catalysts, ethylene trimerization reaction was accomplished in 40 ml of dry toluene, at 80°C and 25 bar ethylene pressure and in the presence of methylaluminoxane (Al/Cr = 700) within 30 min. The supported chromium catalysts were found to be efficient and selective for the ethylene trimerization reaction. The highest activity (74 650 g1‐hexene gCr?1 h?1), as well as no polyethylene formation during reaction processes, was observed when TiO2 was used as the catalyst support.  相似文献   

8.
The crystal structure of EMIm diaquobis(μ‐oxalato)chromate(III) (1‐ethyl‐3‐methylimidazolium chromium(III) dioxalate dihydrate) was determined from X‐ray single crystal diffraction studies. A pale violet crystal of good optical quality was used for the structure determination at –100(2) and 25(2) °C. The basic crystallographic data for the low temperature structure are as follows: triclinic symmetry, space group P$\bar{1}$ , a = 7.6202(8) Å, b = 9.7668(9) Å, c = 10.7171(11) Å, α = 109.257(9)°, β = 90.494(8)°, γ = 105.685(8)°, V = 720.75(1) Å3. The crystal structure was solved by direct methods and refined (using anisotropic displacement parameters for all non‐hydrogen atoms) to a final residual of R1 = 0.039 for 2062 independent observed reflections [I > 2σ(I)]. The compound is built up from alternating layers parallel to (010) containing (EMIm)+ cations or Cr(C2O4)2(H2O)2 anions, respectively. The two crystallographically independent Cr(C2O4)2(H2O)2 octahedra reside on centers of symmetry (Wyckoff sites 1a and 1f). The corners of the octahedra consist of four oxygen atoms from two oxalate groups and two additional water molecules. EMIm+ cations provide linkage between different octahedral layers by hydrogen bridging. The water molecules in turn form hydrogen bonds with adjacent octahedra within the same layer. According to DTA/TG experiments the present compound shows several thermal processes in the range between room temperature and 1000 °C. However, pyrolysis is reproducibly yielding pure inorganic composites, qualifying this novel organic‐inorganic hybrid salt also as a stable precursor for nanoscalar ceramic materials. The final product consists of a distinct mixture of Cr2O3 and Cr3C2 in the molar ratio of 1:1. Concomittant oxide and carbide formation is an unprecedented disintegration pathway of the thermal treatment of oxalatochromates without reducing atmosphere.  相似文献   

9.
Novel inorganic–organic yolk–shell microspheres based on Preyssler‐type NaP5W30O11014? polyoxometalate and MIL‐101(Cr) metal–organic framework (P5W30/MIL‐101(Cr)) were synthesized by reaction of K12.5Na1.5[NaP5W30O110], Cr(NO3)3·9H2O and terephthalic acid under hydrothermal conditions at 200°C for 24 h. The as‐prepared yolk–shell microspheres were fully characterized using various techniques. All analyses confirmed the incorporation of the Preyssler‐type NaP5W30O11014? polyoxometalate into the three‐dimensional porous MIL‐101(Cr) metal–organic framework. The results revealed that P5W30/MIL‐101(Cr) demonstrated rapid adsorption of cationic methylene blue (MB) and rhodamine B (RhB) with ultrahigh efficiency and capacity, as well as achieving rapid and highly selective adsorption of MB from MB/MO (MO = methyl orange), MB/RhB and MB/RhB/MO mixtures. The P5W30/MIL‐101(Cr) adsorbent not only exhibited a high adsorption capacity of 212 mg g?1, but also could quickly remove 100% of MB from a dye solution of 50 mg l?1 within 8 min. The effects of some key parameters such as adsorbent dosage, initial dye concentration and initial pH on dye adsorption were investigated in detail. The equilibrium adsorption data were better fitted by the Langmuir isotherm. The adsorption kinetics was well modelled using a pseudo‐second‐order model. Also, the inorganic–organic hybrid yolk–shell microspheres could be easily separated from the reaction system and reused up to four times without any change in structure or adsorption ability. The stability and robustness of the adsorbent were confirmed using various techniques.  相似文献   

10.
Materials having both magnetic and catalytic properties have shown great potential for practical applications. Here, a reduced graphene oxide/iron oxide/silver nanohybrid (rGO/Fe3O4/Ag NH) ternary material was prepared by green synthesis of Ag on pre‐synthesized rGO/Fe3O4. The as‐prepared rGO/Fe3O4/Ag NH was characterized using Fourier transform infrared spectroscopy, X‐ray diffractometry, Raman spectroscopy, vibrating sample magnetometry, transmission electron microscopy and energy‐dispersive X‐ray spectroscopy. rGO sheets were covered with Fe3O4 (8–16 nm) and Ag (18–40 nm) nanoparticles at high densities. The mass percentages were 13.47% (rGO), 62.52% (Fe3O4) and 24.01% (Ag). rGO/Fe3O4/Ag NH exhibited superparamagnetic behavior with high saturated magnetization (29 emu g−1 at 12 kOe), and efficiently catalyzed the reduction of 4‐nitrophenol (4‐NP) with a rate constant of 0.37 min−1, comparable to those of Ag‐based nanocatalysts. The half‐life of 4‐NP in the presence of rGO/Fe3O4/Ag NH was ca 1.86 min. rGO/Fe3O4/Ag NH could be magnetically collected and reused, and retained a high conversion efficiency of 94.4% after the fourth cycle. rGO/Fe3O4/Ag NH could potentially be used as a magnetically recoverable catalyst in the reduction of 4‐NP and environmental remediation.  相似文献   

11.
Nanostructured spinel-type M(M = Mg, Co, Zn)Cr2O4 oxides with novel adsorbents for aqueous Congo red removal were synthesized by a polyacrylamide gel method and studied for their phase structure, microstructure, adsorption performance, and multiferroic behavior. The phase structure and purity analysis revealed that the nanostructured spinel-type M(M = Mg, Co, Zn)Cr2O4 oxides presented a spinel-type cubic structure, and the formation of a secondary phase such as Cr2O3, MgO, ZnO, or Co3O4 was not observed. The microstructure characterization confirmed that the spinel-type MCr2O4 oxides grew from fine spherical particles to large rhomboid particles. Adsorption experiments of spinel-type MCr2O4 oxides for adsorption of Congo red dye were fitted well with the pseudo-second-order kinetics. The adsorption capacity of the ZnCr2O4 oxide (44.038 mg/g, pH 7, temperature 28 °C, initial dye concentration 30 mg/L) was found to be higher than that of MgCr2O4 oxide (43.592 mg/g, pH 7, temperature 28 °C) and CoCr2O4 oxide (28.718 mg/g, pH 7, temperature 28 °C). The effects of initial adsorbent concentration, initial dye concentration, pH, and temperature between the ZnCr2O4 oxide and Congo red dye at which optimal removal occurs, were performed. The thermodynamic studies confirmed that a high temperature favors the adsorption of Congo red dye onto ZnCr2O4 oxide studied. The nanostructured spinel-type M(M = Mg, Co, Zn)Cr2O4 oxides that exhibited high adsorption performance for adsorption of Congo red dye can be ascribed to the synergistic effect of electrostatic interaction, pore filling, and ion exchange. The present work suggested that the nanostructured spinel-type M(M = Mg, Co, Zn)Cr2O4 oxides have excellent adsorption performance and multiferroic behavior, which shows potential applications for removal of the Congo red dye from wastewater, magnetic memory recording media, magnetic sensor, energy collection and conversion device, and read/write memory.  相似文献   

12.
Isothermal oxidation behavior of chromium with and without nanometric sol-gel CeO2 coating is studied at 1000℃ in air. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are used to examine the surface morphology and microstructure of their oxide films. It is found that ceria coating greatly improves the anti-oxidation property of chromium. Laser Raman spectrometer and X-ray diffraction spectrometer (XRD) are also used to study the stress level in oxide films formed on ceria-coated and ceria-free Cr. The difference in oxidation behavior is mainly attributed to the fact that ceria greatly reduces the growth speed and grain size of Cr2O3 film, and this fine grain-sized Cr2O3 film probably has better high temperature plasticity, i.e. oxide film can relieve parts of compressive stress by means of creeping. XRD and Raman testing results both show the stress declination due to nano-CeO2 application, and their deviation is analyzed conceming to the rare earth effect.  相似文献   

13.
The cluster anion {Ge9[Si(SiMe3)3]3} ( 1 ) is transferred intact into the gas phase via the electro spray method. Subsequently the fragmentation of 1 after resonant excitation as well as the oxidation reaction with O2 and Cl2 are investigated in an FT‐ICR mass spectrometer (Fourier Transform Ion Cyclotron Resonance). Unlike former results with off‐resonant excitation the fragmentation leads mainly to the end‐product Ge9. Moreover, applying an on‐resonant excitation the dissociation experiment can be quantified; 2.0 ± 0.15 eV (193 ± 15kJ · mol–1) for the elimination of the first two ligands and 2.7 ± 0.15 eV (261 ± 15 kJ · mol–1) for all ligands, respectively. Particular attention is turned on the first step, where sterically encumbered Si2(SiMe3)6 molecules are formed in a concerted reaction. This result, which is also important for elemental reactions on metal surfaces in catalyses, is based on experimentally determined threshold energies, DFT calculations and calculations on the lifetime of the involved species., In contrast to the high reactivity of crystalline 1 ·Li(THF)4, gaseous 1 is inert against oxygen. The analogy to recently published spin forbidden reactions of Al13 with O2 hints to a general importance of spin conversion during gas phase reactions of larger cluster molecules. The oxidation of 1 with Cl2 proceeds through different reaction channels. DFT calculations give a first insight on the complex primary oxidation steps. These calculations also reveal that the delocalized bonding situation in the Ge9 core is distorted upon oxidation. This result together with the dissociation experiments shed more light on differences and similarities between metalloid clusters and Zintl ions.  相似文献   

14.
15.
The chemical compatibility of perovskite-type Ba0.5Sr0.5Co0.8Fe0.2O3?δ (BSCF) oxides with Cr2O3 has been examined between room temperature and 1,100 °C. Differential thermal analysis and thermogravimetric analysis were used to analyze the thermal behavior of BSCF–Cr2O3 binary mixtures in all composition ranges (0–100 mass% BSCF). The reaction products were identified by X-ray analysis after heating at 700–1,100 °C. As we expected, it was found that perovskite-type BSCF oxide had a poor chemical compatibility with the Cr2O3 oxide. In particular, the decomposition process of the BSCF–Cr2O3 binary mixture is quite complex and it starts at about 700–750 °C. The mixtures of BSCF and Cr2O3 oxides reacted forming mixed complex oxides based on (Ba/Sr)FeO3, (Co/Fe)CrO4, and (Ba/Sr)CrO4 mixtures.  相似文献   

16.
Verproside, isovanilloylcatalpol, catalposide and 6‐O‐veratroyl catalpol are bioactive iridoid glucosides isolated from in a number of folk medicinal plants. A rapid, sensitive and selective liquid chromatography/mass spectrometric (LC/MS) method for the simultaneous determination of verproside, isovanilloylcatalpol, catalposide and 6‐O‐veratroyl catalpol in rat plasma was developed. The analytes were extracted from 50 µL of rat plasma with ethyl acetate using 7‐carboxymethyloxy‐3',4',5‐trimethoxyflavone as internal standard and analyzed on an X‐Bridge C18 column within 6.5 min with 40% methanol in 10 mm ammonium formate (pH 3.0). The analytes were quantified using an electrospray ionization mass spectrometry in the selected ion monitoring mode. The standard curves were linear over the concentration ranges of 10–2000 ng/mL for verproside, isovanilloylcatalpol and catalposide and 20–2000 ng/mL for 6‐O‐veratroyl catalpol. The coefficients of variation and relative errors of verproside, isovanilloylcatalpol, catalposide and 6‐O‐veratroyl catalpol for intra‐ and inter‐assay at four quality control levels were 2.5–8.0 and–4.0–6.6%, respectively. This method was successfully applied to the pharmacokinetic study of verproside and its possible metabolite isovanilloylcatalpol after intravenous administration of verproside, a candidate anti‐asthma drug, in male Sprague–Dawley rats. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

17.
The surface oxidation of FeCr alloys with 18, 28, and 43 mass‐% Cr was investigated in situ using grazing‐incidence X‐ray absorption spectroscopy (GIXAS) at the chromium and iron K‐edges. Oxidation in air was monitored in situ in the temperature range from 290 K to 680 K. The standard GIXAS data analysis is extended for the treatment of a single layer model in order to estimate the chromium concentrations of the oxide layer and of the near‐interface substrate as well as the oxide layer thickness. XANES analysis shows transitions from b.c.c. Fe to corundum type Fe2O3 and from b.c.c. Cr to corundum type Cr2O3. The initial oxide layers are 1.1‐1.4 nm thick and contain 60‐90 mass‐% chromium, while the near‐interface substrate is depleted in Cr. During heating, iron oxide growth dominates up to 560‐600 K. Then the chromium oxide layer loses its passivation effect and Cr oxidation sets in.  相似文献   

18.
《Solid State Sciences》2001,3(1-2):121-132
The structures of the tetramethylammonium dichromate, [(CH3)4N]2Cr2O7 and trichromate, [(CH3)4N]2Cr3O10, were determined from single-crystal X-ray diffraction data. These compounds crystallize in the orthorhombic system (space group Pnma, with Z=4 and a=17.192(1) Å, b=8.55(1) Å, c=10.637(1) Å), for the dichromate and in the monoclinic system (space group P21/n, with Z=4 and a=11.366(2) Å, b=8.493(2) Å, c=20.187(4) Å, β=103.98(3)° for the trichromate. The structures consist of discrete dichromate anions (Cr2O7)2– or trichromate anions (Cr3O10)2–, respectively, stabilized by quaternary ammonium [(CH3)4N]+. Phase transitions in [(CH3)4N]2Cr2O7 have been evidenced by differential scanning calorimetry as well as a new allotropic variety of [(CH3)4N]2Cr2O7 which was characterized by X-ray powder diffraction. It crystallizes in an orthorhombic system with the unit cell parameters a=24.49(1) Å, b=8.85(1) Å, c=8.705(8) Å.  相似文献   

19.
The new compounds Pr8(C2)4Cl5 (1), Pr14(C2)7Cl9 (2), Pr22(C2)11Cl14 (3), Ce2(C2)Cl (4), La2(C2)Br (5), Ce2(C2)Br (6), Pr2(C2)Br (7), Ce18(C2)9Cl11 (8), and Ce26(C2)13Cl16 (9) were prepared by heating mixtures of LnX3, Ln and carbon or in an alternatively way LnX3, and “Ln2C3–x” in appropriate amounts for several days between 750 and 1200 °C. The crystal structures were investigated by X‐ray powder analysis (5–7) and/or single crystal diffraction (1–4, 8, 9). Pr8(C2)4Cl5 crystallizes in space group P21/c with the lattice parameters a = 7.6169(12), b = 16.689(2), c = 6.7688(2) Å, β = 103.94(1) °, Pr14(C2)7Cl9 in Pc with a = 7.6134(15), b = 29.432(6), c = 6.7705(14) Å, β = 104.00(3) °, Pr22(C2)11Cl14 in P21/c with a = 7.612(2), b = 46.127(9), c = 6.761(1) Å, β = 103.92(3) °, Ce2(C2)2Cl in C2/c with a = 14.573(3), b = 4.129(1), c = 6.696(1) Å, β = 101.37(3) °, La2(C2)2Br in C2/c with a = 15.313(5), b = 4.193(2), c = 6.842(2) Å, β = 100.53(3) °, Ce2(C2)2Br in C2/c with a = 15.120(3), b = 4.179(1), c = 6.743(2) Å, β = 101.09(3) °, Pr2(C2)2Br in C2/c with a = 15.054(5), b = 4.139(1), c = 6.713(3) Å, β = 101.08(3) °, Ce18(C2)9Cl11 in P$\bar{1}$ with a = 6.7705(14), b = 7.6573(15), c = 18.980(4) Å,α = 88.90(3) °, β = 80.32(3) °, γ = 76.09(3) °, and Ce26(C2)13Cl16 in P21/c with a = 7.6644(15), b = 54.249(11), c = 6.7956(14) Å, β = 103.98(3) ° The crystal structures are composed of Ln octahedra centered by C2 dumbbells. Such Ln6(C2)‐octahedra are condensed into chains which are joined into undulated sheets. In compounds 1–4 three and four up and down inclined ribbons alternate (4+4, 4+33+4–, 4+43+44+3), in compounds 8 and 9 four and five (4+5, 5+44+54+4), and in compounds 4–7 one, one ribbons (1+1) are present. The Ln‐(C2)‐Ln layers are separated by monolayers of X atoms.  相似文献   

20.
Knudsen effusion mass spectrometry was used to study vaporization processes and thermodynamic properties of twenty samples of chromium‐containing slags in the CaO‐MgO‐Al2O3‐Cr2O3‐FeO‐SiO2 system in the temperature range 1850–2750 K. Tungsten cells were used and Cr2O3 solid was used as a reference material. The system was calibrated using liquid gold. As FeO was the first emanating vapor species, monitoring of the chromium‐containing species could be carried out only after the complete vaporization of FeO. This, however, was found to have very little impact on the concentration of the slags investigated. During the measurements, the ion current intensities of CrO+ and CrO species in the mass spectra of the vapor over the CaO‐MgO‐Al2O3‐Cr2O3‐FeO‐SiO2 samples were monitored and compared with those corresponding to solid Cr2O3. Data on the partial pressures of vapor species as well as the activities of Cr2O3 as a function of temperature were obtained. The results are expected to be valuable in the optimization of slag composition in high alloy steelmaking processes. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

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