Academic literature on the topic 'Manganese carbide'
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Journal articles on the topic "Manganese carbide"
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Karen, Pavel, and Bohumil Hájek. "Hydrolysis of manganese carbides Mn5C2 and Mn23C6." Collection of Czechoslovak Chemical Communications 51, no. 8 (1986): 1628–35. http://dx.doi.org/10.1135/cccc19861628.
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Diffractographically pure manganese carbides Mn5C2 and Mn23C6 were hydrolyzed with water at 25 and 60 °C. Based on the model of contracting spherical particles in the carbide powder particulate system, the corrosion rates were calculated from the course of gas evolution during the hydrolysis; the values obtained were as follows in μm/h: Mn5C2: 1.2 ± 0.4 at 25 °C and 10 ± 3 at 60 °C, and Mn23C6: 0.15 ± 0.01 at 25 °C and 2.2 ± 0.2 at 60 °C. The hydrolysis gives rise to hydrogen and a concentration-decreasing sequence of predominantly saturated hydrocarbons, the fraction of C2 and higher hydrocarbons being about 6 times lower for Mn23C6 than for Mn5C2. The hydrogen and hydrocarbon contents of the mixture after hydrolysis are consistent with the assumed reaction course, where the adsorbed active hydrogen, formed during the hydrolysis reaction due to the metallic nature of the carbide, partly reacts with the methane arising from the hydrolysis of the C1 groups in the carbide and partly combines to molecular hydrogen.
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Linnarsson, M. K., and A. Hallén. "Manganese in silicon carbide." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 273 (February 2012): 127–30. http://dx.doi.org/10.1016/j.nimb.2011.07.056.
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Iker, Mathieu, D. Gaude-Fugarolas, Pascal J. Jacques, and Francis Delannay. "Improvement of the Mechanical Properties of High Manganese Steels by Combination of Precipitation Hardening and Mechanical Twinning." Advanced Materials Research 15-17 (February 2006): 852–57. http://dx.doi.org/10.4028/www.scientific.net/amr.15-17.852.
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Twinning-Induced Plasticity steels (TWIP steels) are extensively studied due to their ultra-high strain-hardening rate, that brings about a remarkable combination of ductility and strength. Twinning can be observed in high manganese-carbon steels. This paper considers hardening by combination of mechanical twinning with carbide precipitation. The kinetics of precipitation and the morphological evolution of carbides with annealing time were studied for two different TWIP steels with high manganese and carbon contents. The steels are first cold-rolled and then annealed at 800°C for recrystallization and carbide precipitation. Depending on the steel composition, the kinetics of precipitation and the morphology of the carbides are quite different. The influence of the annealing cycle on the mechanical properties has also been assessed. The results are used to discuss the influence of composition, stacking fault energy (SFE) and carbide precipitation on twinning. We show that the usual criteria based on the SFE only are not sufficient to characterize the twinning ability of a steel.
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Byelikov, S., I. Volchok, and V. Netrebko. "Manganese Influence on Chromium Distribution in High-Chromium Cast Irons." Archives of Metallurgy and Materials 58, no. 3 (September 1, 2013): 895–97. http://dx.doi.org/10.2478/amm-2013-0095.
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Abstract It is shown that chromium distribution in the metal base of high-chromium cast irons depends on manganese content. According to the X-ray micro-spectral analysis data with the increase of manganese content from 0.72 to 6.49% chromium content decreased in the near-carbide zones. At the same time chromium content in carbides increased. This process obtained particularly strong development inside eutectic colonies of carbides. As a result of it, when total chromium content in the alloy has been 23%, its concentration in the local zones was 12,3%, thus the necessary level of corrosion resistance has not been provided. The minimal chromium content has to amount 23.2%, at 6.49% Mn and 2.2...2.5% C in order to provide corrosion resistance of high-chromium cast irons
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Feng, Yi Fan, Ren Bo Song, Shi Guang Peng, Chang Hong Cai, and Zhi Dong Tan. "Effect of Aging Temperature on Microstructure and Properties of V Alloyed High Manganese Austenitic Steel." Materials Science Forum 898 (June 2017): 766–71. http://dx.doi.org/10.4028/www.scientific.net/msf.898.766.
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The effect of aging temperature on microstructure and mechanical properties of Fe-16Mn-1.3C-0.3V steel was investigated. After a series of heat treatment experimental processes, including solution treatment at 1080 oC for 1 h then aging treatment at 350 oC, 400 oC, 450 oC, 500 oC and 550 oC for 1 h respectively, the microstructure of V alloyed high manganese austenitic steels were studied using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The experimental steel had the best comprehensive performance after aging treated at 450 oC for 1 h. It presented hardness of 249HB, impact toughness of 215 J·cm-2, tensile strength of 707 MPa, yield strength of 421 MPa and elongation of 30.8%. With the aging temperature increased, the amount of precipitates increased and precipitates gradually transformed from globularity to needle. EDS analysis showed the most striking difference between two types carbides. That the globular carbide had a lot of vanadium element, which could cause the hardness of globular carbide higher than needle-like carbide. TEM showed the size of these globular carbide particles were 10~100 nm. SADP demonstrated that the fine globular precipitate was vanadium carbide (VC).
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Kolli, R. Prakash, and David N. Seidman. "Co-Precipitated and Collocated Carbides and Cu-Rich Precipitates in a Fe–Cu Steel Characterized by Atom-Probe Tomography." Microscopy and Microanalysis 20, no. 6 (September 25, 2014): 1727–39. http://dx.doi.org/10.1017/s1431927614013221.
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AbstractThe composition of co-precipitated and collocated NbC carbide precipitates, Fe3C iron carbide (cementite), and Cu-rich precipitates are studied experimentally by atom-probe tomography (APT). The Cu-rich precipitates located at a grain boundary (GB) are also studied. The APT results for the carbides are supplemented with computational thermodynamics predictions of composition at thermodynamic equilibrium. Two types of NbC carbide precipitates are distinguished based on their stoichiometric ratio and size. The Cu-rich precipitates at the periphery of the iron carbide and at the GB are larger than those distributed in the α-Fe (body-centered cubic) matrix, which is attributed to short-circuit diffusion of Cu along the GB. Manganese segregation is not observed at the heterophase interfaces of the Cu-rich precipitates that are located at the periphery of the iron carbide or at the GB, which is unlike those located at the edge of the NbC carbide precipitates or distributed in the α-Fe matrix. This suggests the presence of two populations of NiAl-type (B2 structure) phases at the heterophase interfaces in multicomponent Fe–Cu steels.
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Tarraste, Marek, Jakob Kübarsepp, Kristjan Juhani, Märt Kolnes, Mart Viljus, and Arvo Mere. "Sintering of High Mn Cemented Carbides in Mn-Rich Environment." Defect and Diffusion Forum 405 (November 2020): 402–7. http://dx.doi.org/10.4028/www.scientific.net/ddf.405.402.
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The economic, environmental and healthcare aspects are pushing cemented carbide industry to reduce or even avoid the usage of conventional binder metals – nickel and cobalt. Commonly, austenitic Fe-Ni alloys have been preferred choice for substituting Co. Similar to Ni, manganese acts as austenite stabilizer and studies have shown that Fe-Mn alloys offer alternative binder metal to Co and Ni in cemented tungsten carbides. In addition, Fe-Mn as a binder potentially offers improved wear resistance due to the well-known wear properties of Fe-Mn-C steels. Addition of chromium to the binder composition increases corrosion performance of composite. Cemented carbides bonded with austenitic FeCrNi binder have demonstrated promising performance. In present work the possibility of achieving austenitic binder phase through substitution of nickel by manganese as an austenite stabilizer is investigated. Structure formation, phase composition and mechanical performance of WC-FeMn and WC-FeCrMn cemented carbides are discussed.
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Chubukov, M. Yu, D. V. Rutskii, and N. A. Zuyban. "Investigation of the Influence of the Chemical Composition of Tubular Steels on the Features of the Formation of Phase Constituents during the Solidification of Continuously Cast Billets by Computer Simulation." Materials Science Forum 945 (February 2019): 598–602. http://dx.doi.org/10.4028/www.scientific.net/msf.945.598.
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The paper presents the results of modeling the features of the formation of the main phase constituents and carbide phases during solidification and cooling of a continuously cast billet from low carbon pre-peritectic and peritectic steels used for the production of seamless pipes. As a result of calculation using the software system Fact Sage, it was found that with a carbon content in the range from 0.04% to 0.20%, and when vanadium and niobium carbide elements are introduced into the composition of carbide-forming elements of mass fraction to 0.08%, a change occurs phase composition of steels in different temperature ranges. Positive dynamics in the part of increasing the content of δ-ferrite and narrowing of the crystallization interval by transferring steel to the pre-peritectic class are noted. The temperature intervals for the separation of carbide and carbon-nitride phases in steels with different chemical compositions have been established. A comparative study of steels with manganese-vanadium / manganese-vanadium-niobium and steels with a manganese-silicon alloying system showed a significant difference in the separation of carbonitride phases in the temperature range 1200-800 ° C due to the formation of high-temperature constituents.
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Wang, Jing, Si Jing Fu, Shu Yong Jiang, and Hong Cheng. "Study on Titanium Carbide Particles Reinforced High Manganese Steel Composite." Advanced Materials Research 557-559 (July 2012): 232–35. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.232.
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High manganese matrix composite, reinforced by TiC particles, was synthesized in situ by means of conventional powder metallurgy route. The microstructure was investigated by means of Scanning electron microscopy. Pin-on-disc dry sliding wear tests had been carried out to study the wear behavior of TiC-reinforced high manganese steel matrix composites. The results show that TiC carbides are distributed uniformly in the composite. The abrasive wear resistance of the composites is higher than that of the unreinforced high manganese steel.
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Riebisch, M., B. Pustal, and A. Bührig-Polaczek. "Influence of Carbide-Promoting Elements on the Microstructure of High-Silicon Ductile Iron." International Journal of Metalcasting 14, no. 4 (March 9, 2020): 1152–61. http://dx.doi.org/10.1007/s40962-020-00442-1.
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Abstract Because of its low cost, steel scrap is one of the most important raw materials for the production of ductile iron (DI). The amount of carbide-promoting elements in steel scrap, such as chromium, manganese, molybdenum, niobium and vanadium, is expected to increase in the future. Most of these elements have a negative impact on the microstructure and mechanical properties of DI. The solubility of carbide-promoting elements in solid solution-strengthened DI materials, standardized in DIN EN 1563:2011, is modified by the high silicon content. For these new materials, the tolerance limits for carbide-promoting elements and their mutual influence must be known to ensure a sustainable production process. To investigate the individual and combined impact of carbide-promoting elements on the carbide content in high-silicon ductile iron EN-GJS-500-14, experimental investigations and thermodynamic–kinetic microstructure simulations were carried out. Microstructure was characterized using metallographic analysis, and quantitative relations between chemical composition and microstructure were developed by means of regression analysis. Besides this quantitative analysis, it was found that the formation of grain boundary carbides can be detected via thermal analysis. Furthermore, experiments and simulations showed that vanadium promotes the formation of chunky graphite in high-silicon DI castings.
Dissertations / Theses on the topic "Manganese carbide"
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Akil, Cem. "Optimization Of Conditions To Produce Manganese And Iron Carbides From Denizli-tavas Manganese Ore By Solid State Reduction." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608188/index.pdf.
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Main purpose of this study was to find the optimum conditions to produce a charge material for ferromanganese production or steelmaking with high content of iron and manganese carbides from Denizli-Tavas manganese ore by carbothermic reduction and investigate the effects of temperature, time, amount of active carbon addition and CaO addition on this reduction.
The ore was calcined and then mixed with active carbon and CaO. Experiments were performed in a horizontal tube furnace that can be heated up to 1700 ºC with MoSi2 heating elements. After each experiment weight loss data were obtained and converted to percentage reduction. X-Ray, SEM-EDS and chemical analyses were done in order to determine whether or not carbide phases have been obtained, and calculate the composition of the product. Considering the experimental results, the optimum conditions found for reduction of Denizli-Tavas manganese ore were 1250 °
C, 4 hours, 100% of stoichiometric amount of active carbon and 5% CaO addition. Under the optimum conditions 83.85% reduction of calcined ore was obtained.
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Kononov, Ring Materials Science & Engineering Faculty of Science UNSW. "Carbothermal solid state reduction of manganese oxide and ores in different gas atmospheres." Publisher:University of New South Wales. Materials Science & Engineering, 2008. http://handle.unsw.edu.au/1959.4/41459.
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The aim of the project was to establish rate and mechanisms of solid state reduction of manganese ores. The project studied carbothermal reduction of manganese oxide MnO, two Groote Eylandt (Australian) and Wessels (South African) manganese ores in hydrogen, helium and argon atmospheres at temperatures up to 1400C for MnO and 1200C for manganese ores. Experiments were conducted in the fixed bed reactor with on-line off-gas analysis. The major findings are as follows. ?? Rate and degree of reduction of MnO and ores increased with increasing temperature. ?? Reduction of MnO and manganese ores at temperatures up to 1200C was faster in helium than in argon, and much faster in hydrogen than in helium. The difference in MnO reduction in hydrogen and helium decreased with increasing temperature to 1400C. ?? Addition of up to 7 vol% of carbon monoxide to hydrogen had no effect on MnO reduction at 1200C. ?? In the process of carbothermal reduction of ores in hydrogen at 1200C, silica was reduced. ?? Reduction of both GE ores was slower than of Wessels ore. This was attributed to high content of iron oxide in the Wessels ore. ?? Carbon content in the graphite-ore mixture had a strong effect on phases formed in the process of reduction; thus, in the reduction of Wessels ore with 12-16 wt% C, a-Mn and Mn23C6 were formed; when carbon content was above 20 wt%, oxides were reduced to carbide (Mn,Fe)7C3. ?? Kinetic analysis showed that mass transfer of intermediate CO2 from oxide to graphite in carbothermal reduction in inert atmosphere was a contributing factor in the rate control. ?? High rate of reduction of manganese oxide in hydrogen was attributed to formation of methane which facilitated mass transfer of carbon from graphite to oxide. Hydrogen was also directly involved in reduction of manganese ore reducing iron oxides to metallic iron and higher manganese oxides to MnO. Reduction of Wessels and Groote Eyland Premium Fines ores in the solid state is feasible at temperatures up to 1200C; while temperature for solid state reduction of Groote Eyland Premium Sands is limited by 1100C.
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Reed, Izumi N. "Effect of chromium and manganese on corrosion behavior of Fe-TiC composites." Full text open access at:, 1998. http://content.ohsu.edu/u?/etd,276.
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Gao, Pengcheng. "Matériaux carbonés nanostructurés pour supercapacités électrochimiques." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20028/document.
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Différents matériaux carbonés nanostructurés ont été synthétisés et mis en oeuvre comme matériaux supercapacitifs à double couche électrochimique (EDLC) ou comme substrats de matériaux pseudocapacitifs avec pour objectif d'augmenter leur densité de puissance. Nous avons ainsi développé une méthode de synthèse simple et originale de carbures de silicium (SiC) qui procède par une réduction topotactique d'un composite silice/carbon par le magnésium. Du fait de la température de synthèse inférieure à 800°C, SiC résultant conserve la morphologie et/ou la structure poreuse du précurseur composite. Par cette approche, nous pouvons moduler la structure poreuse ordonnée de SiC à façon, développer des porosités hiérarchiques méso/macro, préparer des feuillets ou des fibres de SiC. Les différentes formes de SiC ont été converties par chloration en autant de carbones, opération introduisant une microporosité supplémentaire. En électrolyte organique, ces carbones à porosité hierarchique combinent à la fois des capacités importantes issues de la microporosité mais également des performances inégalées en terme de puissance du fait de la méso ou macro-porosité associée. Dans une approche différente, des feuillet de graphène ont été décorés par voie sol-gel non-hydrolytique (micro-onde en milieu alcool benzilique) par des nanoparticules de FeOx. Le composite FeOx/graphene résultant combine simultanément les comportements EDLC et pseudocapacitif du graphène et de FeOx. Du fait de sa structure particulière, le composite FeOx/graphene conserve les performances en puissance du graphène auxquelles s'ajoutent celles d'énergie de FeOx. Nous avons également décoré des nanofibres de carbone avec des carbones mésoporeux. Après dépôt de MnO2 birnessite, les composites gagnent à la fois en capacité et en puissance en particulier avec des carbones présentant des pores supérieurs à 10nmVarious nanostructured carbon materials were synthesized and further served as active materials of electrical double layer capacitor or substrates of pseudocapacitive materials in order to improve power capability of corresponding supercapacitor. On the one hand, a simple synthesis of porous silicon carbides (SiCs) was achieved by performing a topotactic thermal reduction by magnesium (Mg) of a silica/ carbon composite. Thanks to the low synthetic temperature (below 800 ºC), the SiCs well preserved the pristine skeletons of their silica/carbon precursors. Successively, the SiCs with diverse porous structures from their silica/carbon precursor emerged, e.g. ordered tunable mesoporous SiCs, 3D-hierarchical meso and macroporous SiC, SiC nanosheet and SiC nanofiber. Furthermore, the porous SiCs derived from magnesio-thermal reduction were reduced to hierarchical carbons with newborn narrow distributed microporosity by chlorination. In an organic electrolyte, the hierarchical carbon combines the high specific capacitance from narrow distributed microporosity and the outstanding rate capability from ordered-arranged meso or macroporosity that make it promising for high power and energy density capacitor. On the other hand, a “benzyl alcohol route” has been used to decorate RGO nanosheets with FeOx nanoparticles. The resulting FeOx/ RGO composite, due to their hybrid nanostructure, combine both EDLC capacitive and pseudocapacitive bahaviors of RGO and FeOx, respectively. Thanks to the laminated RGO and nano FeOx particles film, the resulting composite gains the same power capability as RGO and a higher energy density than raw FeOx. Furthermore, mesoporous carbon was introduced to adorn the CNF surface through self-assemble of resol, carbon nanofiber(CNF) and Pluronic@127. After further coating with birnessite-MnO2, the composite electrode gains extra capacitance and power improvement in presence of superficially coating mesoporous carbon with pore size larger than 10nm
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Nohair, Khaddouj. "Formation de liaison carbone-carbone par addition radicalaire de composés fonctionnalisés sur des oléfines : amorcage par Mn(III) formé "in situ" par voie électrochimique." Paris 12, 1991. http://www.theses.fr/1991PA120046.
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La these presente la mise au point d'une nouvelle methode de realisation de reactions d'addition radicalaire dans laquelle on associe un amorcage par des quantites catalytiques d'un complexe de manganese (iii) et la regeneration electrochimique de l'espece organometallique oxydante. Nous avons realise par cette methode l'addition de composes a hydrogene mobile ainsi que l'addition d'halogenures d'alkyle sur des olefines. Le procede est applicable aux olefines terminales ou cycliques ainsi qu'aux dienes non conjugues. Les composes a hydrogene mobile sont directement oxydes par l'acetate manganique. Pour les autres composes, on associe au sel de manganese un compose oxydable en un radical qui reagit ensuite avec l'halogenure. Les olefines terminales ou cycliques donnent avec les composes halogenes des produits d'addition avec de bons rendements. Les reactions mettant en jeu des dienes lineaires 1,6 et le cyclopenta-1,5-diene conduisent a des produits de cyclopentaniques. Par contre avec l'hexa-1,5-diene on obtient un produit de mono-addition lineaire. Les avantages de la methode resident principalement dans le fait que les reactions sont realisees a temperature ambiante ou voisine de l'ambiante, en atmosphere ordinaire, et dans un solvant polaire (l'acide acetique ou le methanol). Ce travail montre par ailleurs que les adduits polyhalogenes obtenus par addition radicalaire peuvent etre transformes ulterieurement par electroreduction en composes cycliques a trois ou cinq carbones selon la nature du reactif
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Johnson, Tony Richard. "Vinylidene and cyclic carbene chemistry of iron and manganese half-sandwich complexes." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340247.
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Martin, Thomas Antony. "Unravelling the photochemistry of organometallic N-heterocyclic carbene complexes." Thesis, University of Bath, 2011. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.547630.
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This thesis describes the synthesis, characterisation and reactivity of new manganese and rhenium(I) NHC complexes, which have been investigated both thermally and photochemically and the results contrasted with existing phosphine analogues in the literature. Cp’Mn(CO)2(NHC) (NHC = IEt2Me2 1, IMes 2, IiPr2Me2 3 and IPr 4) were synthesised and investigated by TRIR spectroscopy. Loss of CO was observed after 355 nm irradiation to form agostically stabilised intermediates, which reformed the parent species by recombination with CO on the nanosecond timescale. Loss of NHC was not observed, in contrast to Cp’Mn(CO)2(PPh3) which lost both CO and PPh3 upon photolysis. [Re(NHC)(Bpy)(CO)3]BAr4F (NHC = IEt2Me2 5, IMes 6) were synthesised and investigated by TRIR spectroscopy and UV/Vis absorption and emission spectrometry. Inclusion of an NHC altered the excited state manifold of the complexes, favouring population of the 3MLCT over the 3IL excited state. The lowest energy excited state for both 5 and 6 proved to be a 3MLCT excited state at 298 and 77 K. In contrast, [Re(PPh3)(Bpy)(CO)3]BAr4F exhibited 3MLCT at 298 K, but 3IL at 77 K. A series of complexes, M(NHC)(CO)4X and M(NHC)2(CO)3X (M = Re, X = Cl; M = Mn, X = Br) formed upon reaction of the corresponding M(CO)5X species and free NHC. The substitution pattern was dictated by the steric bulk of the NHC. Generation of the corresponding cations by halide abstraction was investigated. M(NHC)2(CO)3X was found to form agostic stabilised species upon halide abstraction by NaBAr4F in CH2Cl2. Under the same conditions, Re(IPr)(CO)4Cl was found to form the dichloromethane complex, [Re(IPr)(CO)4(η1-CH2Cl2)]BAr4F. In C6H5F solution under an atmosphere of dihydrogen, the CH2Cl2 ligand could be displaced by H2 to form the dihydrogen species, [Re(IPr)(CO)4(H2)]BAr4F.
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Van, der Westhuizen Belinda. "Synthetic investigation of Mn(I) and Re(I) N-heterocyclic carbene complexes." Diss., University of Pretoria, 2010. http://hdl.handle.net/2263/25922.
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The study involves synthetic approaches towards the preparation of novel NHC complexes of low valent rhenium and manganese transition metals. Diverse methods of synthesis were studied. The direct approach, in which the ylidene obtained from deprotonation of 1,3-bis(2,4,6- trimethylphenyl)imidazolium chloride was added to the metal substrate, proved to be unsuccessful as isolation of the free carbene should rather be performed in an argon filled glove box under extreme inert conditions. By way of further investigation the ylidene was prepared by in situ methods and then quenched with the metal substrate. Different bases for deprotonation purposes and reaction conditions were explored. All routes employed were investigated and compared using group VII transition metal substrates Re(CO)5Br, Mn(CO)5Br, Re2(CO)10 and Mn2(CO)10. Isolation and purification of these products proved to be very challenging due to the insolubility in some organic solvents with consequent problematic spectroscopic analyses of the complexes. The tendency of the products to undergo various side reactions is observed in all reactions. Specifically, hydrolysis of the imidazolium ligand, followed by vinyl formation, yielded the mesitylformamide compound (3). The results obtained for some of the monometal substrates indicated that the target complexes were formed but could not be isolated. However, the synthesis route employing deprotonation by nBuLi as base and [Mn2(CO)10] as dimetal substrate lead to the isolation of the target dinuclear complex [Mn2(CO)9IMes] (9). Other novel complexes obtained during the course of this study include the biscarbene tetrarhenium complex [Re2(CO)9.C(OEt)C4H2OC(OEt)Re2(CO)9] (12) and various side reaction products. In many cases, metal-metal bond cleavage and carbonyl insertion was observed, as is evident in the complex IMesH[ReO4] (6) and ketene product (13). Structural and theoretical studies were performed to investigate the bond character between the carbene ligand and the metal.Dissertation (MSc)--University of Pretoria, 2010.
Chemistry
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Zheng, Jianxia. "Earth-abundant metal complexes for catalyzed hydroelementation." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S148/document.
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Ce travail de recherche est consacré au développement de catalyseurs à base de métaux de transition abondants de la première rangée du tableau périodique, tels que Mn, Fe, et Ni, pour les réactions d'hydro-élémentation. Tout d'abord, l'hydrosilylation de cétones et d'aldéhydes a été accomplie en utilisant un système catalytique simple Ni(OAc)₂ 4H2O/PCy₃ avec le PMHS, silane peu coûteux et stable en tant que source d'hydrure. L'amination réductrice d'aldéhydes avec des amines a également été réalisée avec le même système catalytique et le TMDS, comme silane. Deuxièmement, l’efficacité des complexes de manganèse demi-sandwich CpMn(CO)₂(IMes) a été prouvée pour la réduction des aldéhydes et des cétones en présence de Ph₂SiH₂ (1,5 équiv.) sous irradiation UV. La transformation difficile d'acides carboxyliques en aldéhydes a été effectuée à l'aide de Mn₂(CO)₁₀ et de Et3SiH. Troisièmement, la méthylation des amines secondaires avec le carbonate de diméthyle en tant que source C1 a été démontrée dans des conditions catalytique douces avec [CpFe(CO)₂(IMes)]I. Ensuite, l'hydroboration d'alcènes et d'alcynes fonctionnalisés a été réalisée en présence d’un complexe de fer (0), Fe(CO)₄(IMes) sous irradiation UV. Enfin, la réaction d'hydroboration a été étendue avec succès à la réduction de CO₂ en methoxyboranes avec Fe(CO)₃[P(OPh)₃]₂ en tant que catalyseur et les diverses sources de borane, tels que HBpin, HBcat ou 9-BBNThis research work deals with the use of the catalysts based on the earth-abundant transition metals of the first row of the periodic table, such as Mn, Fe, and Ni, for hydroelementation reactions. First of all, the hydrosilylation of aldehydes and ketones was accomplished using a simple Ni(OAc)₂ 4H₂O/PCy₃ catalytic system with the inexpensive and stable silane PMHS as the hydride source. The reductive amination of aldehydes with amines was also achieved with the same catalytic system and TMDS, as the silane. Second, the efficiency of manganese half-sandwich complex CpMn(CO)₂(IMes) was exemplified for the reduction of aldehydes and ketones in the presence of Ph ₂ SiH ₂ (1.5 equiv.) under UV irradiation at room temperature. Still with manganese, the challenging transformation of carboxylic acids to aldehydes was performed using commercial Mn₂ (CO)₁₀ and Et₃SiH. Third, the methylation of the secondary amines with dimethyl carbonate as an alternative and safe C1 source was demonstrated under mild conditions with [CpFe(CO)₂(IMes)]I as the catalyst. Then, the hydroboration of functionalized alkenes and alkynes was catalyzed by an iron(0) carbonyl complex Fe(CO)₄(IMes) under UV irradiation. Finally, the hydroboration reaction was successfully extended to the reduction of CO₂ to methoxyboranes with Fe(CO)₃[P(OPh)₃]₂ as the catalyst and the borane sources, such as HBpin, HBcat or 9-BBN
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Bauvineau, Laurent. "Approche locale de la rupture ductile : application à un acier carbone-manganèse." Paris, ENMP, 1996. http://www.theses.fr/1996ENMP0794.
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Cette etude concerne la dechirure ductile a 300c d'un acier au carbone-manganese presentant une forte teneur d'inclusions de sulfure de manganese. Le programme experimental a porte sur des eprouvettes fissurees et axisymetriques entaillees. Des eprouvettes fissurees originales (sent et ct avec petites fissures) ont ete employees et ont montre que les parametres j#l#c et dj/da ne sont pas des caracteristiques intrinseques au materiau mais dependent de la geometrie de l'eprouvette employee. L'etude sur les eprouvettes entaillees a mis en evidence l'influence de la taille de celles-ci sur les valeurs a rupture : les variations observees sont de plus de 25% sur les deformations moyennes a rupture. Les mecanismes de rupture sont etudies sur des coupes metallographiques, des examens fractographiques et des essais in situ. La naissance de l'endommagement se caracterise par la rupture ou la decohesion des sulfures de manganese qui sont regroupes en amas. Une analyse inclusionnaire appuyee par des acquisitions en analyse d'images et un traitement avec les cellules de voronoi a permis de definir les grandeurs associees aux inclusions. La simulation de la dechirure ductile a ete effectuee a l'aide de l'approche locale de la rupture. Plusieurs modeles d'endommagement ont ete utilises pour simuler la rupture de ce materiau. Les modeles, dits decouples, nous ont permis de reproduire les effets de la geometrie sur la tenacite a l'amorcage j#l#c. Le developpement de modeles, dits semi-couples, avec l'appui des resultats obtenus en analyse d'images permet de decrire les effets de geometrie et d'echelle pour des structures non fissurees. La representation de l'ensemble des observations experimentales (effet de la geometrie sur les courbes j-a, effet d'echelle) a ete possible grace aux modeles couples (potentiels de gurson et de rousselier). Une comparaison entre l'approche locale et l'approche globale a deux parametres a ete egalement abordee.
Book chapters on the topic "Manganese carbide"
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Storms, E. K. "Manganese Carbide." In Inorganic Reactions and Methods, 315. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470145265.ch123.
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Sarbas, Bärbel, and Wolfgang Töpper. "Native Element, Solid Solution, Silicide, and Carbide." In Mn Manganese, 9–13. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-662-08907-1_2.
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Ignacio, Jose. "Reinforcement of Austenitic Manganese Steel with (TiMo) Carbide Particles Previously Synthesized by SHS." In Advances in Ceramics - Synthesis and Characterization, Processing and Specific Applications. InTech, 2011. http://dx.doi.org/10.5772/17044.
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Oshima, K. "Manganese–Carbene Complexes." In Compounds of Groups 7-3 (Mn..., Cr..., V..., Ti..., Sc..., La..., Ac...), 1. Georg Thieme Verlag KG, 2003. http://dx.doi.org/10.1055/sos-sd-002-00032.
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Oshima, K. "Manganese–Carbyne Complexes." In Compounds of Groups 7-3 (Mn..., Cr..., V..., Ti..., Sc..., La..., Ac...), 1. Georg Thieme Verlag KG, 2003. http://dx.doi.org/10.1055/sos-sd-002-00040.
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Oshima, K. "From Manganese–Carbene Complexes." In Compounds of Groups 7-3 (Mn..., Cr..., V..., Ti..., Sc..., La..., Ac...), 1. Georg Thieme Verlag KG, 2003. http://dx.doi.org/10.1055/sos-sd-002-00042.
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Taber, Douglass F. "C–H Functionalization." In Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.003.0021.
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Konstantin P. Bryliakov of the Boreskov Institute of Catalysis devised (Org. Lett. 2012, 14, 4310) a manganese catalyst for the selective tertiary hydroxylation of 1 to give 2. Note that the electron-withdrawing Br deactivates the alternative methine H. Bhisma K. Patel of the Indian Institute of Technology, Guwahati selectively oxidized (Org. Lett. 2012, 14, 3982) a benzylic C–H of 3 to give the corresponding benzoate 4. Dalibor Sames of Columbia University cyclized (J. Org. Chem. 2012, 77, 6689) 5 to 6 by intramolecular hydride abstraction followed by recombination. Thomas Lectka of Johns Hopkins University showed (Angew. Chem. Int. Ed. 2012, 51, 10580) that direct C–H fluorination of 7 occurred predominantly at carbons 3 and 5. John T. Groves of Princeton University reported (Science 2012, 337, 1322) an alternative manganese porphyrin catalyst (not illustrated) for direct fluorination. C–H functionalization can also be mediated by a proximal functional group. John F. Hartwig of the University of California, Berkeley effected (J. Am. Chem. Soc. 2012, 134, 12422) Ir-mediated borylation of an ether 9 in the position β to the oxygen to give 10. Uttam K. Tambar of the UT Southwestern Medical Center devised (J. Am. Chem. Soc. 2012, 134, 18495) a protocol for the net enantioselective amination of 11 to give 12. Conversion of a C–H bond to a C–C bond can be carried out in an intramolecular or an intermolecular sense. Kilian Muñiz of the Catalan Institution for Research and Advanced Studies cyclized (J. Am. Chem. Soc. 2012, 134, 15505) the terminal alkene 13 directly to the cyclopentene 15. Olivier Baudoin of Université Claude Bernard Lyon 1 closed (Angew. Chem. Int. Ed. 2012, 51, 10399) the pyrrolidine ring of 17 by selective activation of a methyl C–H of 16. Jeremy A. May of the University of Houston found (J. Am. Chem. Soc. 2012, 134, 17877) that the Rh carbene derived from 18 inserted into the distal alkyne to give a new Rh carbene 19, which in turn inserted into a C–H bond adjacent to the ether oxygen to give 20.
Conference papers on the topic "Manganese carbide"
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Nabti, Zineb, Tarik Bordjiba, Sara Bezzazi, and Imane Saidia. "Electrodeposition of manganese oxide on carbon paper and their applications in renewable energies Electrodeposition de l’oxyde de manganese sur le papier de carbone et leurs applications en énergies renouvelables." In 2018 International Conference on Electrical Sciences and Technologies in Maghreb (CISTEM). IEEE, 2018. http://dx.doi.org/10.1109/cistem.2018.8613576.
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Gra˚berg, Stig, Lars Volden, and Anthonius Johannes Paauw. "Mid Thickness Delayed Cracking of Z-Quality Offshore Steel." In ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-49003.
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During fabrication of a steel structure for an offshore modification project, delayed cracking was experienced in the mid plane or centre line of a 30 mm thick plate. The plate was part of a restraint box frame where 25 mm plates were welded to this 30 mm plate on both plate-surfaces. The applied 30 mm plate was a higher strength offshore steel (EN10225-S420 G2+M), with special through thickness properties and enhanced chemical composition as defined in material data sheet MDS Y30 of NORSOK M-120. Fracture mechanical testing including KV and CTOD in the mid plane confirmed that a very low toughness was present here with a brittle fracture type (cleavage). The plate was manufactured by the continuous casting process which due to centre line segregation resulted in high levels of manganese sulfide inclusions but also niobium carbides/nitrides. The plate manufacturer considered the documented toughness level as expected. Similar testing was performed on a 30 mm plate also delivered to the same material specification but of which the material certificate revealed a 10 times lower sulfur and phosphorus content indicating a much higher steel refinement. A significant higher toughness was obtained for this steel with high ductile behavior. Both steels showed a similar through thickness ductility, measured elongation for the through thickness tensile specimen, which implies that this property does not guaranty for the observed material behavior.
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Pourkia, Navid, Pirooz Marashi, Rouzbeh Leylabi, Seyed Alireza Tabatabaei, and Hadi Torshizi. "The Effect of Weld Metal Manganese Content on the Microstructure, Mechanical Properties and Hot Crack Susceptibility of Helically Welded Linepipes." In 2008 7th International Pipeline Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/ipc2008-64152.
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The effect of manganese addition on decreasing hot crack susceptibility of submerged arc welding in microalloyed steels is well understood, but its increment should not cause unsuitable changes in metallurgical and mechanical properties of weld metal. Therefore, since weld metal Mn content in SAW process is mainly controlled by welding wire composition, the aim of this investigation is to study the effect of wire Mn content on the microstructure, mechanical properties and hot crack susceptibility of helical linepipes weld metal. In this regard, three different wires with 0.88, 1.05 and 1.54 wt% of Mn content were selected and welding was performed in both experimental and production process condition of X70 helical linepipes. As a result, 1.26, 1.44 and 1.67 wt% of Mn in weld metal was obtained respectively. Metallographical examinations using optical and scanning electron microscopy showed that, increasing the amount of Mn in weld metal, decrease the grain size of all phases (acicular ferrite, primary ferrite and ferrite with aligned second phase). Moreover, in the expense of increasing acicular ferrite, the volume fraction of primary ferrite (mostly grain boundary ferrite) and ferrite with aligned second phase decreased. Also, the results of mechanical properties indicated that the higher the amount of Mn, the higher the strength and hardness of weld metal, but in the case of impact toughness and tensile elongation, an optimum level was observed and lower toughness in the highest Mn content weld metal is attributed to the increasing hardenability and thus formation of martensite/retained austenite islands and grain boundary carbides in coincident sites of acicular ferrite grains. Moreover, analyzes in more than 1000m helical linepipes weld metal length showed that increasing weld metal Mn content up to 1.4wt%, reduced the possibility of hot crack formation from total percentage of 0.005 to around 0.001.