Manganese Carbide Research Articles

High-Pressure Synthesis and Recovery of Single Crystals of the Metastable Manganese Carbide, MnCx.

Transition metal carbides find widespread use throughout industry due to their high strength and resilience under extreme conditions. However, they remain largely limited to compounds formed from the early d-block elements, since the mid-to-late transition metals do not form thermodynamically stable carbides. We report here the high-pressure bulk synthesis of large single crystals of a novel metastable manganese carbide compound, MnCx (P63/mmc), which adopts the anti-NiAs-type structure with significant substoichiometry at the carbon sites. We demonstrate how synthesis pressure modulates the carbon loading, with ~40 % occupancy being achieved at 9.9 GPa.

Study on the Alkali–Sulfur Co-Activation and Mechanical Properties of Low-Carbon Cementitious Composite Materials Based on Electrolytic Manganese Residue, Carbide Slag, and Granulated Blast-Furnace Slag

Industrial solid waste is characterized by complex mineral phases and various components. Low-carbon cementitious materials can be prepared through precise regulation based on the material composition and properties of various industrial solid wastes. In this study, electrolytic manganese residue (EMR), carbide slag (CS), and granulated blast-furnace slag (GBFS) were used as alternatives to cement to prepare multicomponent solid waste cementitious materials. The effects of the proportions of EMR and CS on the cementitious activity of GBFS and the activation mechanism of alkali and sulfur were studied. The results showed that with increasing EMR content, the strength first increased and then decreased. At a GBFS content of 20%, CS content of 2%, and EMR content of 8%, the compressive strength was highest, reaching 45.5 MPa after 28 days of curing, mainly because the OH− in CS and SO42− in EMR synergistically stimulated the active components in GBFS. Hydrated products such as ettringite and hydrated calcium silicate (C–S–H gel) were generated and interlaced with each other to improve the densification of the mortar. Overall, the proposed system provides an avenue to reduce or replace the production of cement clinker and achieve the high-value-added utilization of industrial solid waste.

Niobium’s Effect on the Properties of a Quasi-High-Entropy Alloy of the CoCrFeMnNi System

Niobium’s Effect on the Properties of a Quasi-High-Entropy Alloy of the CoCrFeMnNi System

To the question of improving the wear resistance of high manganese steel castings

Nowadays, one of the most significant tasks in production of equipment for mining industry is import substitution. In this regard, investigations aimed at improving the technologies of manufacturing high quality castings from wear resistance manganese austenitic steels seems to be relevant. The results of metallographic research of high manganese steel samples from foundries producing crushing plates and crushing cones, track links, hammers, shovel teeth, tooth caps etc. are given. Analysis of the microstructure of the presented castings showed that they are characterized by a coarse-grained structure with an austenite grain size of 1–2 points. In most cases, a thickened grain boundary, presence of manganese carbides along the grain boundaries and non-metallic inclusions are observed. The revealed mi-crostructure features of castings are one of the main indicators of low wear resistance of high manganese steel parts. The operational and technological factors affecting the wear resistance of castings are listed. Recommendations for improving the quality of steel products made from manganese steels are proposed, and the results of using original complex modifiers developed at NPP Technology Company in real manufacturing conditions are presented.

Resistance spot weldability of Fe‐15.4Mn‐2.1Al‐1.2C twinning induced plasticity steel

AbstractWelding of twinning induced plasticity steels contains problems due to high manganese constituent. Low manganese and high carbon included twinning induced plasticity steels have not studied throughly in the literature. In this study, resistance spot weldability of Fe‐15.4Mn‐2.1Al‐1.2C twinning induced plasticity steel was investigated. According to the results, interfacial, partial interfacial and pull‐out type failure modes were obtained in tensile‐shear tests. The maximum tensile‐shear load was measured as 17.7 kN with 125 J ⋅ Ω−1 heat input rate separated with pull‐out failure. Although the heat affected zone was narrow, it formed the weakest region of the joint. Cleavage facets which is a sign of brittle fracture were detected on the fracture surface that formed in heat affected zone. A sudden increase in hardness supports the brittleness of the heat affected zone. Also, grain coarsening reduced strength of the heat affected zone. A narrow partially melted zone was identified between heat affected zone and weld nugget. According to electron back scatter diffraction phase distribution analysis, formation of manganese carbides was detected in the heat affected zone.

Study on the influence of manganese and silicon carbide in Al7075 metal matrix composite produced by P/M route

The aluminium alloy-silicon carbide composite is widely used in the aircraft industry such as fuselage skins of aircraft, fuel entree covers and ventral fins in aircraft because of its low weight to high strength ratio, excellent corrosion protection at high temperatures and wear resistance and high hardness. In this work, powders of aluminium alloy 7075 (Al7075) is strengthened with silicon carbide (SiC) and manganese (Mn) in diverse fractions using a powder metallurgy approach to produce specimens of Al7075, Al7075 + 15 %Mn, Al7075 + 15 %Mn + 5 %SiC, Al7075 + 15 %Mn + 10 %SiC, Al7075 + 15 %Mn + 15 %SiC, and Al7075 + 15 %Mn + 20 %SiC. After fabricating, the specimens are subjected to microstructural analysis, X-ray diffraction (XRD), density, Rockwell hardness, and corrosion to find their suitability in engineering applications. The microstructure reveals the uniform dispersion of SiC and Mn in the Al7075 matrix. The hardness value decreases while increasing the SiC content above 15 % due to brittleness, but with the addition of Mn, the hardness value decreases as Mn induces ductility. It is inferred that the experimental density is lesser than the theoretical density due to the presence of small pores in the sample. Corrosion rate lowers with the inclusion of Mn to AL7075 and further decreases with higher fractions of SiC from 5 to 20 %.

Unveiling the atomic position of C in Mn5Ge3Cx thin films

Heavily carbon-doped ${\mathrm{Mn}}_{5}{\mathrm{Ge}}_{3}$ is a unique compound for spintronics applications as it meets all the requirements for spin injection and detection in group-IV semiconductors. Despite the great improvement of the magnetic properties induced by C incorporation into ${\mathrm{Mn}}_{5}{\mathrm{Ge}}_{3}$ compounds, very little information is available on its structural properties and the genuine role played by C atoms. In this paper, we have used a combination of advanced techniques to extensively characterize the structural and magnetic properties of ${\mathrm{Mn}}_{5}{\mathrm{Ge}}_{3}{\mathrm{C}}_{x}$ films grown on Ge(111) by solid phase epitaxy as a function of C concentration. The increase of the Curie temperature induced by C doping up to 435 K is accompanied by a decrease of the out-of-plane $c$-lattice parameter. The Mn and C chemical environments and positions in the ${\mathrm{Mn}}_{5}{\mathrm{Ge}}_{3}$ lattice have been thoroughly investigated using x-ray absorption spectroscopy techniques (x-ray absorption near-edge structures and extended x-ray absorption fine structures) and scanning transmission electronic microscopy (STEM) combined to electron energy loss spectroscopy for the chemical analysis. The results have been systematically compared to a variety of structures that were identified as favorable in terms of formation energy by ab initio calculations. For $x\ensuremath{\le}0.5$, the C atoms are mainly located in the octahedral voids formed by Mn atoms, which is confirmed by simulations and seen for the first time in real space by STEM. However, the latter reveals an inhomogeneous C incorporation, which is qualitatively correlated to the broad magnetic transition temperature. A higher C concentration leads to the formation of manganese carbide clusters that we identified as ${\mathrm{Mn}}_{23}{\mathrm{C}}_{6}$. Interestingly, other types of defects, such as interstitial Ge atoms, vacancies of Mn, and their association into line defects have been detected. They take part in the strain relaxation process and are likely to be intimately related to the growth process. This paper provides a complete picture of the structure of ${\mathrm{Mn}}_{5}{\mathrm{Ge}}_{3}{\mathrm{C}}_{x}$ in thin films grown by solid phase epitaxy, which is essential for optimizing their magnetic properties.

Influence of Cold Deformation on Carbide Precipitation Kinetics in a Fe-22Mn-0.45C TWIP Steel

The carbide precipitation kinetics in a Fe-22Mn-0.45C TWIP steel subjected to three different cold-deformation levels, annealed at various temperatures, were studied. The studied carbides included chemical compositions, morphology, precipitation sites, volume fraction, and size. Manganese carbides were precipitated in a temperature range between 525 and 650 °C. Volume fraction increased with cold-deformation and decreased with annealing temperature. Carbide size increased with cold-deformation and annealing temperatures up to 625 °C, suffering a notable reduction at 650 °C. Precipitation kinetics were described by means of precipitation curves for 0.1% (vol.) of Fe-Mn-carbides. A kinetic model was used, and two stages were found. Complementarily, austenite grain size and microhardness were also measured. With increases in annealing time, microhardness decreased until it reached a nearly constant value, indicating that recrystallization was complete, while, with increases in annealing temperature, grain size increased.

Study of Manganese Recovery in the CaO-SiO<sub>2</sub>-MgO-Al<sub>2</sub>O<sub>3</sub>-MnO-Fe<sub>2</sub>O<sub>3</sub> System by Thermodynamic Simulation

The results of thermodynamic simulation of the manganese recovery in the CaO-SiO2-MgO-Al2O3-MnO-Fe2O3 system by carbon are presented. Parameters of the initial system are temperature range 1400-at a step of , a total pressure of 0.1 MPa, and N2. The composition of the oxide system is corresponded by the manganese ore (wt %) 1.1 MnO2, 44.3 MnO, 28.4 CaO, 9.3 SiO2, 5.4 MgO, 0.3 Al2O3, 11.2 Fe2O3 and silicomanganese slag. It contains (wt %) 16.3 MnO, 18.4 CaO, 52 SiO2, 7.8 MgO, 5.26 Al2O3, and 0.24 FeO. The amount of silicomanganese slag in the system was 0, 5, 12, and 25%. Carbon is used as a reducing agent. Its consumption is increased by 5% from the stoichiometry for the recovery of Fe and Mn and by 8% of the metal mass for the formation of iron, manganese, and silicon carbides. The simulation is carried out using HSC Chemistry 6.12 () software package. The thermodynamic characteristics of the Fe3C, Fe2O3, FeO, MnO2, Mn, Mn3C, Mn5C2, Mn7C3, Mn23C6, and SiC compounds existing in the database are refined. It was determined that an increase in the melt temperature from 1400 to increases the degree of manganese recovery (ηMn) for all compositions of the systems. An increase of the silicomanganese slag content in the mixture from 0 to 25% decreases ηMn from 89.3 to 85% at and from 95.8 to 91.5% at . The chemical composition of the high-carbon ferromanganese alloy is (wt %): 71.9-72.8 Mn, 16.6-17.9 Fe, 0.015-1.64 Si, and 9-. The simulation results can be used to develop a technology for producing a high-carbon ferromanganese when silicomanganese slag is involved in metallurgical processing.

Synergistic solidification/stabilization of electrolytic manganese residue and carbide slag

Electrolytic manganese residue (EMR) contains high concentrations of NH4+ and heavy metals, such as Mn2+, Zn2+, Cu2+, Pb2+, Ni2+ and Co2+, while carbide slag (CS) contains high amount of OH− and CO32−, both posing a serious threat to the ecosystem. In this study, EMR and CS synergistic stabilization/solidification (S/S) was discussed science CS could stabilize or solidify EMR and simultaneously reduce its corrosive. The results showed that after the synergistic S/S for 24 h when liquid-solid ratio was 17.5% and CS dosage was 7%, Mn2+ and NH4+ leaching concentrations of the S/S EMR were below the detection limits (0.02 mg/L and 0.10 mg/L) with a pH value of 8.8, meeting the requirements of the Chinese integrated wastewater discharge standard (GB 8978–1996). Mn2+ was stabilized as MnFe2O4, Mn2SiO4, CaMnSi2O6, and NH4+ escaped as NH3. Zn2+, Cu2+, Pb2+, Ni2+ and Co2+ in EMR can also be stabilized/solidified because of the react with OH− and CO32− in CS. Chemical cost was only $ 0.54 for per ton of EMR synergistic harmless treatment with CS. This study provided a new idea for EMR cost-effective and environment-friendly harmless treatment.

Synthesis and Corrosion Resistance of FeMnNiAlC10 Multi-Principal Element Compound.

A multi-principal element FeMnNiAlC10 bulk alloy was produced by vacuum arc melting. The same alloy was sintered as a thin film on a silicon substrate by ion beam sputter deposition. The bulk alloy has a multiphase structure the elements predominantly segregating into iron manganese carbides and nickel aluminium phases. The thin film is amorphous without detectable phase segregations. The absence of segregation is attributed to the film composition and deposition onto substrate at temperature below 400 K. The corrosion resistance of the thin film alloy was evaluated in 3.5% NaCl. The FeMnNiAlC10 thin film alloy has better corrosion resistance than 304SS. The hardness of the thin film was approximately 7.2 ± 0.3 GPa and the reduced Young’s modulus was approximately 103 ± 4.6 GPa. FeMnNiAlC10 thin film could be a good candidate for coating oil and gas extraction soft iron infrastructure.

High-Temperature Synthesis of Composite Materials Based on MAX Phases in the Cr–Mn–Al–C System

High-temperature synthesis of cast composite materials in the Cr–Mn–Al–C system with various ratios between the Cr2AlC MAX phase and chromium and manganese aluminides and carbides was studied. Experiments were performed in a universal 3-L reactor under argon pressure Р = 5 MPa. Mixtures of powders of chromium(III) and manganese(II, IV) oxides and calcium peroxide with aluminum (ASD-I) and carbon were used as a charge. The synthesis features and the phase composition and microstructure of the target products are significantly influenced by the reactant ratio in the charge. At the stoichiometric ratio of the components corresponding to the Cr2AlC phase, a cast composite material consisting of the Cr2AlC MAX phase, chromium carbides Cr7C3 and Cr3C2, and chromium aluminide Cr5Al8 is formed. In the course of combustion of the charge with the component ratio corresponding to the Mn2AlC phase, a cast composite material consisting of manganese carbides (Mn3AlC, Mn0.545Al0.42C0.035) and aluminide (MnAl) is formed. When these compositions are combined in an 0.75 : 0.25 ratio, the final product is a composite material consisting of a solid solution based on the Cr2AlC MAX phase, manganese carbides (Mn3AlC), and chromium aluminides (Cr2Al). When these compositions are combined in an 0.5 : 0.5 ratio, the final product is a composite material consisting of the manganese-doped Cr2AlC MAX phase and of manganese (Mn14Al86, Mn22.5Al77.5) and chromium (Cr5Al8) aluminides. The final products were characterized by X-ray diffraction and local microstructural analysis.

Magnetic Levitation of Diamond Modified with Manganese and Bismuth

Operating diamond grits to produce a precise grind tool is need. In order to lift up a diamond grit by magnetic force, the magnetic flux was estimated to be 100 μT/g. Diamond (110) surface was modified with manganese powder at 450°C (720 K) then with bismuth powder at 270°C (540 K) due to its low melting temperature. Manganese carbides were formed on the diamond surface which was confirmed by an X-ray diffraction. A magnet that exhibits ferrimagnetism was formed on the surface, it had a spontaneous magnetism. We conducted to form six small disk magnets at hexagonal apex positions on the diamond (110) by using gold film mask. The magnetic flux measured at the center of the hexagon magnets on was 232 μT at room temperature, and the surface modified diamond grid could be lifted up in the magnetic field between two solenoid coils.

Decorated carbon nanofibers with mixed nickel−manganese carbides for methanol electro-oxidation in alkaline solution

Transition metal carbides were recently investigated in many vital applications due to their satisfactory thermal, mechanical and chemical characteristics. They showed a metallic architecture of the host lattice containing interstitial voids of carbon atoms. In this work, mixed nickel-manganese carbides were synthesized onto carbon nanofibers [NiC–MnC@CNFs] in different proportions using the electrospinning process with subsequent calcination at 800 °C. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) were employed to physically characterize the prepared nanomaterials. Homogeneous distribution of nanometallic particles over CNFs was clearly observed in SEM images. XRD charts detected the formation of mixed metallic carbides of Ni0.98C0.02 and (Mn9C)0.4 formulations in different nanomaterials. Excellent electrocatalytic behavior was displayed by NiC–MnC@CNFs nanocatalysts when methanol molecules were introduced into the alkaline solution. Methanol oxidation current density of 110.34 mA cm−2 was measured at the nanomaterial containing NiAc:MnAc ratio of 90:10 with a lowered Eonset value of 310 mV (Ag/AgCl). The effect of varying methanol concentration and the scan rate during the electro-oxidation reaction on the resultant nanomaterial activity was studied. Moreover, the feasibility of charge transfer step was significantly affected by the chosen potential value. Highly pronounced rate was measured at 450 mV. The chronoamperometric study revealed a promising stability trend with increased steady state oxidation current densities especially at nanopowders with lowered MnAc wt.%. The synergistic effect between mixed metallic carbides and CNFs could account for the improved electrocatalytic properties towards methanol molecules oxidation.

Impact of addition of manganese and boron carbide on aluminium metal matrix composites using powder metallurgy process

Aluminium boron carbide composite forms an important class of low weight high strength composite that is widely used in aerospace and defence industry. Owing to its high cost and brittleness at high concentrations, use of boron carbide is limited up to certain extent. The main purpose of this study is to maximize the strength of aluminium composites by adding boron carbide & manganese in it by powder metallurgy process to obtain better mechanical properties. As the pure Aluminium has a low tensile strength and is less ductile and it can undergo the deformation easily at low temperatures. Small additions of manganese and boron are used to give strength to the alloy and enhance its mechanical strength and cast ability. Powder metallurgy technique is used to make the composites with better mechanical properties. These composites can replace the Aluminium metal and the practical applications can be made into the automobile industry, aerospace applications and military applications. Optimum weight percentage of Aluminium boron & Manganese were mixed in different proportions to make the cylindrical shape samples to determine their strength these samples were made by mixing the powders at 2% 4% 6% and the strength were compared.

New perspective on the interface reaction and morphology evolution in the reduction of manganese silicate for silicomanganese alloy production

SiMn alloy is the largest consumption product in the Mn series alloys. Manganese silicates generated during the pre-treatment procedures of manganese ores are the main ingredient for SiMn alloy production. However, conventional cognition is that manganese and silicon in the silicates are respectively reduced to Mn7C3 and SiC by carbon, and then the carbides interact to form alloy. In current study, pure MnSiO3 was synthesized firstly and then a new perspective on the interface reaction and morphology evolution for the reduction of pure MnSiO3 were investigated via XRD, SEM, XPS and thermodynamics analyses. Interface reaction showed that the MnSiO3 was firstly reduced to manganese carbides and SiO2, and then the SiO2 was further reduced by the carbides to generate SiMn alloy. The intermediate product Mn7C3 played a crucial role since the reduction of SiO2 by newly born Mn7C3 preferentially conducted than the carbon reductant. Morphology evolution of the interface between C and MnSiO3 as well as thermodynamic calculations of Mn-Si-O and Mn-Si-C-O systems were minutely clarified in this work to clarify the reduction mechanism. In addition, decomposition of SiMn alloy to SiC ceramic at 1700 °C was an important inducement to illustrate the frangibility of industrial SiMn alloy product.

Two-dimensional hexagonal manganese carbide monolayer with intrinsic ferromagnetism and half-metallicity

Recent experimentally observed intrinsic ferromagnetism in two-dimensional (2D) van der Waals crystals has ignited substantial interests due to their great potential in spintronic devices. However, their practical applications are hampered by rather low Curie temperature and small magnetic anisotropic energy. Here, we predict from first-principles calculations that the 2D pristine hexagonal manganese carbide (h-MnC) sheet exhibits robust ferromagnetic and half-metallic features with complete spin polarization, sizable magnetic anisotropic energy, and wide half-metallic gap near the Fermi energy level. Moreover, the h-MnC sheet can retain its structure up to the temperature of 1000 K, indicating a highly thermodynamic stability. The Monte Carlo simulations based on the Heisenberg model with single-ion anisotropy predict a Curie temperature of 233 K in 2D h-MnC crystal. We confirm the robustness of the ferromagnetism and half-metallicity against the external strain from −6% to 10%. Also, a feasible experimental fabrication route is proposed to realize the h-MnC monolayer via heterostructure engineering and exfoliation techniques. Overall, the robustness of the half-metallicity in combination with the high-temperature ferromagnetism render the freestanding h-MnC monolayer and even its energetically favorable h-MnC/MoS2 and h-MnC/MoSe2 heterostructures quite promising materials for developing practical spintronic nanodevices.

Reduction behavior of medium grade manganese ore from Karangnunggal during a sintering process in methane gas

In this investigation, manganese has been produced from medium grade manganese ore from Karangnunggal mine (West Java, Indonesia). The effects of keeping it at a temperature of 1200°C in methane gas on the structural properties have been studied. The material’s properties have been characterized on the basis of the experimental data obtained using X-ray fluorescence (XRF), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Fourier Transform Infrared (FTIR) spectroscopy. It has been found that MnO2 is reduced to hausmannite (Mn3O4), manganosite (MnO) and manganese carbide (Mn7C3). An increase of the keeping time up to 45 minutes during the sintering process leads to an increase of the MnO concentration, while at 90 minutes, the concentration decreases. The analysis based on the interpretation of both XRD patterns and FTIR spectrum allows one to explain the blockage in the particle surface of the ore by an increase of the carbon deposition.

Synergic effects of electrolytic manganese residue-red mud-carbide slag on the road base strength and durability properties

The present study was designed to prepare the road base material by using electrolytic manganese residue (EMR), red mud (RM) and carbide slag (CS) as main raw materials. The mix was optimized and mechanical properties, durability, strength formation mechanism and environmental behavior were investigated. X-ray diffraction (XRD), Mercury intrusion porosimetry (MIP), 29Si and 27Al magic-angle spinning (MAS) nuclear magnetic resonance (NMR) and electron probe microanalysis method (EPMA) were used for microstructure characterization. The results show that after curing for 7 days, the EMR-RM-CS exhibited the highest unconfined compressive strength (UCS), showed the best durability, the best pore diameter distribution and critical pore size. Hydration characteristics reveal that C-A-S-H gel and AFt are generated in EMR-RM-CS, which is positive to the form of UCS and durability. 29Si analysis demonstrates that the synergy of EMR, RM and CS has the best polymerized structure. Al in the hydrated pastes exists in the form of AlIV and AlVI, and one part of the dominant AlIV is activated and another one is converted to AlVI. The leaching results meet the Chinese groundwater standards which indicate that EMR-RM-CS system can well solidify the heavy metals. The road base material prepared by EMR not only consumes a significant quantity of solid wastes but also provides a new idea for the synergistic utilization of solid wastes.

Study of the scull composition in the blast furnace hearth of Kosaya Gora steel-works, producing ferromanganese with application of schungite (report 1)

Processes of lining erosion and scull formation effect considerably the blast furnace (BF) campaign duration. Among factors, influencing the processes, impacts are distinguished, stipulated by the kind of smelted product as well as materials used for scull formation. In the BF No. 2 of Kosaya Gora steel-works within the campaign from October 1999 until November 2015, 930,000 t of high-carbon ferromanganese (mainly ФМн78 grade) and 110,000 t of foundry iron were produced. After it stoppage for overhaul, samples of the scull were picked out and studied. It was revealed, that the scull of walls of BF hearth has a laminated structure and consists of crystallization products of metal and slag melts, namely: graphite, iron carbides, manganese carbides, iron, ferromanganese, slag components. At the macro level the scull has a lamellar structure. Since during the last campaign the blast furnace apart from ferromanganese was smelting foundry iron rather long time, in the samples, picked out at the level of iron notch at some distance from the cooler, the scull metallic phase mainly consisted of iron and iron carbide. In the sample picked out at a big distance from the cooler, in the scull metallic phase the following phases were discovered by X-ray structural and Moessbauer methods: ferromanganese; complicated manganese and iron carbides, as well as α-iron. Quantity of slag components in the scull decreases in direction from iron notch level to the hearth that speaks about splitting (still in the BF hearth) slag and metallic components of the heat products. In the scull content different slag components present: silicate (38.3–47.2% SiO2) with high content of К2О + Na2O (до 32.2%), MnO (up to 7.5%) and FeO (up to 33.2%). During the quick cooling of the components on the hearth cooler, different compositions are formed: X-ray amorphous “glassy phase”, olivine composition slags of Ca(Mn,Fe,Mg)SiO4 type, wollastonite, melilite with high amount of iron and manganese. Fine inclusions of titanium nitride are presented in the scull in a small amount, as well as manganese and silicon nitrides and carbonitrides, perofskite CaTiO, the role of which is insignificant in the scull forming.