scholarly journals Binary and ternary interstitial alloys - II. The iron-carbon-nitrogen system

Chemical and X-ray investigation of the reaction of carbon monoxide with iron nitrides and of the reaction of ammonia with iron carbides discloses the existence of iron carbonitrides— a series of new ternary interstitial alloys containing iron, carbon and nitrogen. ζ-phase carbonitrides, with structures similar to those of ζ-iron nitrides, have a range of homogeneity extending approximately from Fe 8 N 4 to Fe 8 C 3 N. The latter is isomorphous with Fe 2 N. Є-phase carbonitrides, which are isomorphous with Є-iron nitrides, have a composition range of approximately 25 to 33 atomic % nitrogen plus carbon, i.e. from Fe 3 X to Fe 2 X , in which the higher carbon concentration limit is not less than 16 atomic %. Probable phase fields for part of the iron-carbon-nitrogen system are given on a ternary diagram. Prolonged reaction of carbon monoxide with iron nitrides results in complete elimination of nitrogen. Below 500° C the product is a carbide of iron, now called iron percarbide, the narrow composition range of which includes Fe 20 C 9 . Above 500° C the product of the same reaction is cementite.

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 984
Author(s):  
Aleksei N. Kruk ◽  
Alexander G. Sokol ◽  
Yurii V. Seryotkin ◽  
Yuri N. Palyanov

Oxidation of native iron in the mantle at a depth about 250 km and its influence on the stability of main carbon and nitrogen hosts have been reconstructed from the isothermal section of the ternary phase diagram for the FeO-Fe3C-Fe3N system. The results of experiments at 7.8 GPa and 1350 °C show that oxygen increase in the system to > 0.5 wt % provides the stability of FeO and leads to changes in the phase diagram: the Fe3C, L, and Fe3N single-phase fields change to two-phase ones, while the Fe3C + L and Fe3N + L two-phase fields become three-phase. Сarbon in iron carbide (Fe3C, space group Pnma) is slightly below the ideal value and nitrogen is below the EMPA (Electron microprobe analysis) detection limit. Iron nitride (ε-Fe3N, space group P63/mmc) contains up to 2.7 wt % С and 4.4 wt % N in equilibrium with both melt and wüstite but 2.1 wt % С and 5.4 wt % N when equilibrated with wüstite alone. Impurities in wüstite (space group Fmm) are within the EMPA detection limit. The contents of oxygen, carbon, and nitrogen in the metal melt equilibrated with different iron compounds are within 0.5–0.8 wt % O even in FeO-rich samples; 3.8 wt % C and 1.2 wt % N for Fe3C + FeO; and 2.9 wt % C and 3.5 wt % N for Fe3N + FeO. Co-crystallization of Fe3C and Fe3N from the O-bearing metal melt is impossible because the fields of associated C- and N-rich compounds are separated by that of FeO + L. Additional experiments with excess oxygen added to the system show that metal melt, which is the main host of carbon and nitrogen in the metal-saturated (~0.1 wt %) mantle at a depth of ~250 km and a normal heat flux of 40 mW/m2, has the greatest oxygen affinity. Its partial oxidation produces FeO and causes crystallization of iron carbides (Fe3C and Fe7C3) and increases the nitrogen enrichment of the residual melt. Thus, the oxidation of metal melt in the mantle enriched in volatiles may lead to successive crystallization of iron carbides and nitrides. In these conditions, magnetite remains unstable till complete oxidation of iron carbide, iron nitride, and the melt. Iron carbides and nitrides discovered as inclusions in mantle diamonds may result from partial oxidation of metal melt which originally contained relatively low concentrations of carbon and nitrogen.


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1422.3-1423
Author(s):  
T. Hoffmann ◽  
P. Oelzner ◽  
F. Marcus ◽  
M. Förster ◽  
J. Böttcher ◽  
...  

Background:Interstitial lung disease (ILD) in inflammatory rheumatic diseases (IRD) is associated with increased mortality. Moreover, the lung is one of the most effected organs on IRD. Consequently, screening methods were required to the detect ILD in IRD.Objectives:The objective of the following study is to evaluate the diagnostic value of lung function test, chest x-ray and HR-CT of the lung in the detection of ILD at the onset of IRD.Methods:The study is designed as a case-control study and includes 126 patients with a newly diagnosed IRD. It was matched by gender, age and the performance of lung function test and chest x-ray. The sensitivity and specificity were verified by crosstabs and receiver operating characteristic (ROC) curve analysis. The study cohort was divided in two groups (ILD group: n = 63 and control group: n = 63). If possible, all patients received a lung function test and optional a chest x-ray. Patients with pathological findings in the screening tests (chest x-ray or reduced diffusing capacity for carbon monoxide (DLCO) < 80 %) maintained a high-resolution computer tomography (HR-CT) of the lung. Additionally, an immunological bronchioalveolar lavage was performed in the ILD group as gold standard for the detection of ILD.Results:The DLCO (< 80 %) revealed a sensitivity of 83.6 % and specificity of 45.8 % for the detection of ILD. Other examined parameter of lung function test showed no sufficient sensitivity as screening test (FVC = Forced Vital Capacity, FEV1 = Forced Expiratory Volume in 1 second, TLC = Total Lung Capacity, TLCO = Transfer factor of the Lung for carbon monoxide). Also, a combination of different parameter did not increase the sensitivity. The sensitivity and specificity of chest x-ray for the verification of ILD was 64.2 % versus 73.6 %. The combination of DLCO (< 80 %) and chest x-ray showed a sensitivity with 95.2 % and specificity with 38.7 %. The highest sensitivity (95.2 %) and specificity (77.4 %) was observed for the combination of DLCO (< 80 %) and HR-CT of the lung.Conclusion:The study highlighted that a reduced DLCO in lung function test is associated with a lung involvement in IRD. DLCO represented a potential screening parameter for lung manifestation in IRD. Especially patients with suspected vasculitis should receive an additional chest x-ray. Based on the high sensitivity of DLCO in combination with chest x-ray or HR-CT for the detection of ILD in IRD, all patients with a reduced DLCO (< 80%) should obtained an imaging of the lung.Disclosure of Interests:None declared


2001 ◽  
Vol 79 (3) ◽  
pp. 263-271
Author(s):  
Paul K Baker ◽  
Michael GB Drew ◽  
Deborah S Evans

Reaction of [WI2(CO)3(NCMe)2] with two equivalents of 1-phenyl-1-propyne (MeC2Ph) in CH2Cl2, and in the absence of light, gave the bis(1-phenyl-1-propyne) complex [WI2(CO)(NCMe)(η2-MeC2Ph)2] (1) in 77% yield. Treatment of equimolar quantities of 1 and NCR (R = Et, i-Pr, t-Bu, Ph) in CH2Cl2 afforded the nitrile-exchanged products, [WI2(CO)(NCR)(η2-MeC2Ph)2] (2-5) (R = Et (2), i-Pr (3), t-Bu (4), Ph (5)). Complexes 1, 2, and 5 were structurally characterized by X-ray crystallography. All three structures have the same pseudo-octahedral geometry, with the equatorial sites being occupied by cis and parallel alkyne groups, which are trans to the cis-iodo groups. The trans carbon monoxide and acetonitrile ligands occupy the axial sites. In structures 1 and 2, the methyl and phenyl substituents of the 1-phenyl-1-propyne ligands are cis to each other, whereas for the bulkier NCPh complex (5), the methyl and phenyl groups are trans to one another. This is the first time that this arrangement has been observed in the solid state in bis(alkyne) complexes of this type.Key words: bis(1-phenyl-1-propyne), carbonyl, nitrile, diiodo, tungsten(II), crystal structures.


2008 ◽  
Vol 1777 ◽  
pp. S71
Author(s):  
Kazumasa Muramoto ◽  
Naoki Nakagawa ◽  
Maki Taniguchi ◽  
Katsumasa Kanda ◽  
Kyoko Shinzawa-Itoh ◽  
...  

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lian Wang ◽  
Juncheng Zhou ◽  
Yuhao Chen ◽  
Liu Xiao ◽  
Guojia Huang ◽  
...  

Abstract An intensity modulated fiber-optic carbon monoxide (CO) sensor by integrating in-situ solvothermal-growth Ag/Co-MOF sensing film is fabricated and evaluated. The Michelson interference sensing structure is composed of single-mode fiber (SMF), enlarged taper, thin-core fiber (TCF), and Ag film as the reflector. Ag/Co-MOF was coated on the cladding of the TCF as the sensing material, and the enlarged taper is located between TCF and SMF as the coupler. The structure, morphology, compositions and thermal stability of the Ag/Co-MOF sensing film were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), etc. The sensitivity of the sensor is 0.04515 dB/ppm, and the fitting parameter of the CO concentration is 0.99876. In addition, the sensor has the advantages of good selectivity, good signal and temperature stability, and it has potential application in trace CO detection.


2011 ◽  
Vol 89 (7) ◽  
pp. 845-853 ◽  
Author(s):  
Sadok Letaief ◽  
Wendy Pell ◽  
Christian Detellier

The clay mineral kaolinite was used as support of gold nanoparticles for heterogeneous catalysis of oxidation reactions, particularly of carbon monoxide oxidation. The application of clay minerals in the preparation of new functional materials provides an alternative approach for the use of these abundant raw materials. To improve the physicochemical properties of kaolinite, as well as to ensure a strong immobilization of the adsorbed species, kaolinite was functionalized by grafting 2-amino-2-methyl-1,3-propanediol on the internal and external surfaces of the octahedral sheets by reaction with the aluminol groups. Gold nanoparticles were then deposited on the external surfaces of the fine particles of the functionalized kaolinite. The resulting gold kaolinite nanohybrid material was characterized by various physicochemical techniques. X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and energy-dispersive X-ray spectrometry confirmed that gold was effectively reduced to the metallic state during adsorption onto the external surfaces of the modified kaolinite. The gold nanoparticles have a narrow size distribution: more than 88% are less than 4 nm in diameter. Gold nanoparticles deposited on kaolinite catalyze the electro-oxidation of carbon monoxide in alkaline solution at room temperature.


2019 ◽  
Vol 61 (12) ◽  
pp. 2375
Author(s):  
В.А. Коморников ◽  
В.В. Гребенев ◽  
И.С. Тимаков ◽  
О.Б. Зайнуллин

Composite proton-conducting materials xCs6H (HSO4) 3 (H2PO4) 4+ (1 - x) AlPO4 were obtained in the composition range (x = 0.9–0.7). The methods of x-ray phase analysis, impedance spectroscopy, electron scanning microscopy studied their physicochemical and transport properties.


Sign in / Sign up

Export Citation Format

Share Document