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We report a combined experimental and theoretical study to ascertain carbon solubility in nickel nanoparticles embedded into a carbon matrix via the one-pot method. This original approach is based on the experimental characterization of the magnetic properties of Ni at room temperature and Monte Carlo simulations used to calculate the magnetization as a function of C content in Ni nanoparticles. Other commonly used experimental methods fail to accurately determine the chemical analysis of these types of nanoparticles. Thus, we could assess the C content within Ni nanoparticles and it decreases from 8 to around 4 at. % with increasing temperature during the synthesis. This behavior could be related to the catalytic transformation of dissolved C in the Ni particles into graphite layers surrounding the particles at high temperature. The proposed approach is original and easy to implement experimentally since only magnetization measurements at room temperature are needed. Moreover, it can be extended to other types of magnetic nanoparticles dissolving carbon. [ABSTRACT FROM AUTHOR]

Carbide-free bainitic steels show attractive mechanical properties but are difficult to process because of the sluggish phase transformation kinetics. A macroscopic model based on the classical nucleation theory in conjunction with the modified Koistinen–Marburger relationship is proposed in this study to simulate the kinetics of incomplete bainitic and martensitic phase transformations with and without austenite deformation. A 0.26C-1Si-1.5Mn-1Cr-1Ni-0.003B-0.03Ti steel and a 0.18C-1Si-2.5Mn-0.2Cr-0.2Ni-0.02B-0.03Ti steel were investigated with different levels of ausforming. The concept of ausforming is expected to accelerate the onset of the bainitic transformation and to enhance the thermodynamic stability of austenite by increased dislocation density. The phase transformation kinetics of both steels is quantitatively analyzed in the study by dilatometry and X-ray diffraction so that the carbon concentration in the retained austenite and bainitic ferrite, as well as their volume fractions, is determined. A critical comparison of the numerical and experimental data demonstrates that the isothermal kinetics of bainite formation and the variation of driving energy can be satisfactorily described by the developed model. This model captures the incompleteness of the bainite phase transformation and the carbon enrichment in the austenite well. A fitting parameter can be used to elucidate the initial energy barrier caused by the ausforming. An increase in austenite stability can be described by the nucleation reaction and the thermodynamic energies associated with the change of dislocation density. The proposed model provides an in-depth understanding of the effect of ausforming on the transformation kinetics under different low-carbon steels and is a potential tool for the future design of heat treatment processes and alloys. [ABSTRACT FROM AUTHOR]

The article presents the discussion on granular technologies for accelerating decarbonization. Topics include low-carbon technological solutions varying in scale from solar panels, e-bikes, and smart thermostats to carbon capture and storage; and focusing on the specific needs of accelerated low-carbon transformation such as rapid technology deployment, escaping lock-in, and social legitimacy.

The sediment characterisation of wetlands belonging to the Northeastern Region of India particularly regarding the assessment of sediment carbon stock is very scanty. The presently available literature on the wetlands cannot be employed as a common model for managing the wetlands of the Northeastern Region of India as wetlands are a sensitive ecosystem with a different origin or endogenous interventions. Thereby, this research was conducted on Deepor Beel for investigating the spatial and seasonal variation of sediment parameters, the relationship between the parameters and pollution status of the wetland. Results revealed that the study area is of an acidic nature with a sandy clay loam type texture. Organic carbon, total nitrogen and available nitrogen were higher in sediments in the monsoon period. The mean stock of the sediment carbon pool of Deepor Beel is estimated to be 2.5 ± 0.7 kg m−2. The average non-residual fraction percentage (63.2%) of Pb was higher than the residual fraction. Zn content ∼490 mg kg−1 exceeding its effect range medium (ERM) was determined to suggest frequent biological adverse effects. Highest metal enrichment factor (EF) values were shown by Zn and Pb, which ranged between 78 and 255. Risk assessment code (RAC) values of Pb between 21 and 29% indicated its high bio-accessibility risk. Pearson's coefficient matrix revealed a low degree of positive correlation between organic carbon content and metal concentration. Principal component analysis revealed that the first component comprising of EC, basic cations and metals accounted for 62.3% of variance while the second component (OM, OC, TN, AN, AP) and the third component (pH) accounted for 21.8% and 7.0% of the variance, respectively. The present study revealed the adverse impact of human inputs on the Deepor Beel quality status. Image 1 • First carbon stock report for freshwater wetland from northeastern region of India. • Carbon stock of Deepor Beel sediment was estimated to be 2.5 ± 0.7 kg m−2 • A significant percentage of Pb present in bioavailable exchangeable fraction. • Zinc was determined with the potential to cause an adverse biological effect. This study suggests a deteriorating sediment quality status of Deepor Beel wetland due to the effect of unchecked regional anthropogenic activities in and around the wetland. [ABSTRACT FROM AUTHOR]

Abstract TiCN/TiNbCN multilayers were deposited on silicon substrates by r.f. magnetron sputtering with alternatively changing the sputtering plasma composition between pure Ti + C and Nb elements under a reactive mixture Ar/N 2. Bilayer period values varied from nanometric range (15 nm) to higher micrometric range (1.5 μm). The coatings structural and stoichiometric properties were analyzed by HAX-ray, X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS) and cross-sectional transmission electron microscopy (HRTEM). The multilayer period and relative thickness were clearly determined, and a growth structure was found on the TiCN/TiNbCN multilayers. Additionally, an epitaxial relationship was found between layers inside each columnar crystallite, given by (111)[110] TiCN //(111)[110] TiNbCN. The mechanical properties showed an evolution as function of bilayer period increase under cube-on-cube epitaxial growth effect. Highlights • Modulation of the niobium signal (83Nb+) in the [TiCN/TiNbCN] 30 multilayer system with superlattices effect. • Cube-on-cube epitaxial growth. • Epitaxial relationship (111)[110]TiCN//(111)[110]TiNbCN. • Thank you very much. [ABSTRACT FROM AUTHOR]

During solidification, the peritectic reaction can occur in a wide range of materials, including ferrous and non-ferrous alloys. The kinetic and thermodynamic principles that govern the peritectic reaction in regard to solute diffusion and phase transformation are well understood, and the negative impact that the peritectic reaction has on the surface quality of as-cast steel products is well documented. In ferroalloys, the peritectic reaction occurs between the hypoperitectic (0.09 pct C) and hyperperitectic (0.53 pct C) regions of the iron-carbon phase diagram. Beside the carbon content, the magnitude of the peritectic reaction in a given steel is affected by the contents of other solute elements. However, our understanding of the effect of all dissolved elements on the peritectic reaction is still evolving. There are over a dozen equations that have been proposed for predicting the peritectic nature of steels. Some of these equations were developed for application to specific groups of steels, chemistries, and casting conditions. In this paper, the predictive power of four peritectic equations is compared to the results from thermal analysis experiments conducted on steels with varying concentrations of dissolved elements. Based on the thermal analysis results, an equation is proposed for calculating the latent heat of the peritectic reaction for a given solute element. [ABSTRACT FROM AUTHOR]

A new type of oxygen-supplying technology was developed for electric arc furnace (EAF) steelmaking using submerged CO2 and O2 mixed injection (S-COMI). S-COMI injects O2 into the molten steel bath directly by a submerged injector installed in the furnace bed; so the metallurgical reactions can be accelerated with a high utilization ratio of oxygen. However, there has been limited research on the impact characteristics of the S-COMI submerged gas jet in EAF steelmaking. In this study, water model experiments and numerical simulations were carried out to analyze the submerged gas jet behavior, and a theoretical model was built to depict the axis trajectory of submerged gas jet in the liquid bath. The numerical results were validated against the water model experiments to show that the gas flow rate and the installed angle have a significant influence on the jet impact characteristics. The results show that as the gas flow rate increases, the horizontal and vertical penetration distances increase; as the installed angle increases, the horizontal penetration distance increases while the vertical penetration distance decreases. In addition, the erosion mechanism of the element around the submerged injector exit was studied. As the installed angle increases, the velocity component in the vertical direction increases, the fluid flow is accelerated, and the wall shear stress of the underpart of the injector element increases. Therefore, the erosion rate of the upper part of the element decreases, while that of the underpart increases. [ABSTRACT FROM AUTHOR]

Abstract The objective of this paper is the investigation of the abrasive wear behavior of tempering steel by the analysis of its deformation behavior and dominant abrasion micro mechanisms under controlled single scratch testing. We analyzed single scratches induced by a sphero-conical diamond tip with constant and progressively increasing load in tempering steel with varying carbon content in the as quenched condition. Among scratch and hardness testing the analysis and characterization included the optical determination of the deformation behavior (SEM, CLSM, AFM). The results show that the deformation behavior strongly depends on applied normal load and strength (yield stress, ultimate tensile strength) as it varies with carbon content. It was shown that an increasing load leads to the transition of predominant abrasion micro mechanisms from ideal micro ploughing to wedge and chip formation. The scratch resistance increased with increasing carbon content until for higher carbon contents a saturation tendency due to the presence of retained austenite is observed. An increasing carbon content also shifted the aforementioned transition of dominant micro mechanisms not only to higher applied normal loads, but also to higher scratch depths. Highlights • Deformation and dominant micro-mechanisms of abrasion were analyzed as a function of carbon content and scratch normal load. • Different deformation regimes that depend on scratch depth and material strength were analyzed. • It is seen a shift of deformation regimes as a function of material strength. [ABSTRACT FROM AUTHOR]

Graphical abstract The nature of synergistic interface between TaC and g-C emerges as an important parameter controlling the catalytic activity. This synergistic interface ensures that not only does the presence of g-C results in higher SSA but also, higher electron mobility by efficient charge transfer. TaC and g-C powders as stable catalyst for both HER (1000 cycles) and degradation of MB dye (4 cycles). Highlights • Photocatalytic and electrocatalytic properties of TaC powders are contrasted. • TaC and g-C powders as stable catalyst for both HER (1000 cycles) and degradation of MB dye (4 cycles). • The nature of synergistic interface between TaC and g-C emerges as an important parameter controlling the catalytic activity. • Phase purity and size of TaC powders are important parameters for electocatalytic and photodegradation reactions. • TaC properties modify and control the adsorption properties of the powder for HER as well as dye degradation reactions. Abstract Nano transition metal carbides (TMCs) have emerged as materials of great interest for different catalytic applications in fuel cells and also as catalysts for photo-treatment of organic effluents in industrial waste water. For both the catalytic phenomenon, the charge transfer pathways between the TMC and the surrounding carbon are of significant importance. In present work, well characterized nano powders of Tantalum Carbide (TaC) have been used as a model system to understand the effect and relative importance of powder parameters such as phase purity, particle size and amount of graphitic carbon (g-C) present (in the powder sample) in determining the performance for Hydrogen Evolution Reaction (HER) and photodegradation of Methylene Blue (MB) dye. For both the applications, TaC particle size and specific surface area (SSA) of the powder emerged as a key parameter. Larger SSA results in better performance even for powder with incomplete TaC phase formation. For same sized TaC, single phase powders give better performance. The SSA of the powders depends on the size of the carbide particles and the g-C present in the powders. The nature of synergistic interface between TaC and g-C emerges as an important parameter controlling the catalytic activity. This synergistic interface ensures that not only does the presence of g-C results in higher SSA but also, higher electron mobility by efficient charge transfer. The study of TaC powders with variable g-C content brought to fore the difference in the reaction pathways of the two catalytic systems in spite of the common requirement of charge transfer from TaC to g-C. As a consequence of the synergistic interface, dye adsorption properties of the g-C are modified by the presence of TaC and can be tailored. XPS, PL and UV data has been used to propose a possible degradation mechanism for the photo-oxidation of MB dye under visible irradiation. [ABSTRACT FROM AUTHOR]

Abstract The carbon is one of the basic alloying solutes in steels. In the present study, the newly carbon microalloyed X80 steel was designed for the next generation of pipeline and the carbon microalloying effect of base material on the crystallographic structure of coarse grained heat affected zone (CGHAZ) of X80 girth welded joints was systematically investigated using electron back-scattering diffraction (EBSD), considering the fact that crystallography is the most intrinsic aspect in evaluating the microstructure. The results indicated a remarkable variation in the density of high angle grain boundaries and their dispersion by increasing the carbon content of 0.03wt%. It was attributed to the differential shearing mechanism, which was primarily sheared by variant pairing of V1/V2 at 0.06 wt% carbon, whereas at lower 0.03wt% carbon, V1/V4 pairing mechanism dominated the transformation. The preferential variant pairing transformation mechanism at differential carbon content therefore generated dissimilarly selected variants. Thus, as the carbon content increased, the variant selection effect upon phase transformation was attenuated by generating more variants from different Bain groups. The variant pair V1/V2 belonging to different Bain groups neighboring in CGHAZ of high carbon steel increased the density of high angle boundary (Σ3 boundary). Moreover, the variation in CTOD (crack-tip opening displacement) property of HAZ suggested that it should be primarily correlated to the block size (or density of block boundaries) of CGHAZ. Graphical Abstract Unlabelled Image Highlights • Microalloying of carbon (0.03 wt%) for base material within a limited scope was beneficial for CGHAZ. • An increase of carbon from 0.03 to 0.06 wt% in base material alters the shearing mechanism of CGHAZ dramatically. • The possible correlation between crystallographic structure of CGHAZ and CTOD property of HAZ was elaborated. [ABSTRACT FROM AUTHOR]

The effect of quenching temperature and tempering time on the microstructure, content of retained austenite and carbon content in retained austenite of a copper and niobium alloyed medium carbon steel were investigated by using optical, electron microscopy and X-ray diffraction. Results showed the microstructure of the quenching–partitioning–tempering steel consisted of lath martensite, retained austenite and carbides. With the increase of quenching temperature, the martensite laths became coarsened and the content of retained austenite increased. With the increase of tempering time, the content of retained austenite initially increased, reached to the maximum at 600 s and then gradually decreased. [ABSTRACT FROM AUTHOR]

Based on the previous study of Cr-containing Fe-0.63C-1.52Mn-1.49Si-0.62Cr-0.036Nb high carbon steel, although normalization process as a pretreatment of quenching–partitioning–tempering (Q-P-T) was performed in this high carbon steel to raise the ductility, its impact toughness only is 7.4 J/cm2. Microstructural characterization reveals that strain-induced twin-type martensite transformed from considerable chunky retained austenite destroys toughness. Therefore, a novel Cr-free Fe-0.67C-1.52Mn-1.49Si-0.038Nb (wt.%) high carbon steel was designed and normalization process as pretreatment of Q-P-T process was still employed so that the volume fraction of retained austenite evidently decreases from 21% to 10%. This high carbon steel not only keeps high tensile strength (1660 MPa) and elongation (29.0%), but also exhibits high impact toughness of 33.2 J/cm2. The high impact toughness is attributed to the elimination of chunky retained austenite accompanying dispersive and fine retained austenite with high mechanical stability, which effectively reduces the formation of brittle strain-induced twin-type martensite during deformation. [ABSTRACT FROM AUTHOR]

Abstract Porous CaSiO 3 ceramics were prepared via a solid-state reaction method using CaCO 3 and SiO 2 as raw materials and active carbon as a pore-forming agent. The results indicated that porous CaSiO 3 ceramics could be obtained under a low sintering temperature of 1320 °C. The addition of active carbon significantly affected the volume density, microstructure, pore size distribution and mechanical strength of porous CaSiO 3 ceramics. With the increase of active carbon content, the volume density decreased, meanwhile the pore size and porosity increased gradually. Besides, the three-point bending tests demonstrated that the mechanical strength was decreased with increasing active carbon content. However, all the porous ceramics still exhibited high mechanical strength. These results implied that the increase of active carbon content not only enlarged the pore size and enhanced the porosity, but also kept a remarkable mechanical strength of porous CaSiO 3 ceramics. Therefore, these rationally designed CaSiO 3 porous ceramics will be a highly potential material in various applications due to its high mechanical strength, low sintering temperature and narrow pore size distribution. [ABSTRACT FROM AUTHOR]

Highlights • Spark testing to measure carbon content based on fractal box counting is proposed. • Box counting analysis is used to calculate the fractal dimension of spark picture. • An exponential function is employed to describe carbon content and fractal dimension. Abstract Spark testing is an effective and inexpensive way to classify the steel materials in industrial practice. Especially, it could determine carbon content in a moment. However, this method has reliance upon the skill and experience of operator. Therefore, computer recognition of spark has been developed to determine carbon content for increasing reliability and efficiency. The numerable high-resolution images of sparks emitting at high speed are taken pictures by camera or mobile phone, then input the images into computer, and calculated the fractal dimension of spark based on fractal box counting method. Result shows that the fractal dimension has a good correlation with carbon content, and the similar natural logarithm function is obtained by a least squares fit through plots of carbon content against fractal dimension. Carbon content measurement error is about 0.06%. It means a convenient and accurate way to identify an unknown carbon steel may be achieved. [ABSTRACT FROM AUTHOR]

Abstract The quenching and partitioning response of intercritically annealed steel with aluminum contents in the 2–3 wt.% range and a carbon content of 0.2 wt.% was studied. Two types of morphologies for retained austenite were observed in electron backscatter diffraction studies: blocky, untransformed austenite grains and partially transformed austenite located primarily at prior austenite and packet boundaries. The amount of retained austenite was found to correlate with the initial quench temperature, as well as with the uniform elongation of the specimens in subsequent tensile testing. The transformation characteristics of austenite were rationalized on the basis of prior austenite grain size and inhomogeneous carbon distribution. The martensite transformed during the initial quench was found to favor Σ3 twin-type lath combinations, supplemented by neighboring variants providing self-accommodation. Graphical Abstract Highlights • The effect of intercritical annealing on Q&P treatments is determined. • The morphology and crystallography of the martensitic phase are investigated. • The blocky-type retained austenite is found to remain primarily at packet and PAG boundaries. • The amount of retained austenite was shown to correlate with both the quench temperature and the elongation of tensile tested specimens. [ABSTRACT FROM AUTHOR]

The low-lying (up to about 40 000 cm-1) doublet and quartet states of AlC have been studied at the CASSCF and MRCI levels of theory. The bonding in the X 4Σ- state is shown to involve three one-electron bonds. The first excited state, a 2Π, lies about 8700 cm-1 higher and like the X 4Σ- state is derived from ground state Al and C, but has a two-electron π bond leading to a much shorter bond length. Those states derived from Al 3s13p2 are much higher in energy, since the promotion energy is not recovered by the formation of two-electron bonds. Transition moments are presented for all the dipole-allowed transitions. The very strong B 4Σ-–X 4Σ- transition near 22 600 cm-1 is probably the best way to observe AlC in either emission or absorption. [ABSTRACT FROM AUTHOR]

Presents a study which examined the defect structure of carbon rich silcon carbide (a-SiC:H) films using optical absorption measurements. Benefits offered by devices based on a-SiC:H; How optical energy gap or the refractive index of films can be varied; Experimental procedure used to conduct the study; Results and discussion of the study.

Highlights • Quantification of predictive uncertainty in data-driven models of power plants. • Multi-objective optimisation under uncertainty to find optimal NOx and UBC trade-off. • Novel solution selection method based on maximum probability of dominance. • Optimisation for all load demands in a single run: no need for repeated optimisation. • Methods are demonstrated on the data collected from Jianbi power plant, China. Abstract Coal remains an important energy source. Nonetheless, pollutant emissions – in particular Oxides of Nitrogen (NOx) – as a result of the combustion process in a boiler, are subject to strict legislation due to their damaging effects on the environment. Optimising combustion parameters to achieve a lower NOx emission often results in combustion inefficiency measured with the proportion of unburned coal content (UBC). Consequently there is a range of solutions that trade-off efficiency for emissions. Generally, an analytical model for NOx emission or UBC is unavailable, and therefore data-driven models are used to optimise this multi-objective problem. We introduce the use of Gaussian process models to capture the uncertainties in NOx and UBC predictions arising from measurement error and data scarcity. A novel evolutionary multi-objective search algorithm is used to discover the probabilistic trade-off front between NOx and UBC, and we describe a new procedure for selecting parameters yielding the desired performance. We discuss the variation of operating parameters along the trade-off front. We give a novel algorithm for discovering the optimal trade-off for all load demands simultaneously. The methods are demonstrated on data collected from a boiler in Jianbi power plant, China, and we show that a wide range of solutions trading-off NOx and efficiency may be efficiently located. [ABSTRACT FROM AUTHOR]

Abstract Porous Fe 3 O 4 /C microspheres, which were Fe 3 O 4 nanocrystals (～8 nm) embedded in an open nanostructured carbon network, were successfully synthesized via a facile hydrothermal process. The porous Fe 3 O 4 /C microspheres possessed many distinct attributes that facilitate efficient broadband electromagnetic wave absorption (EMWA). EMWs were attenuated through multiple reflections and absorption in the 3D interconnected porous structure of the microspheres; these processes collectively improved the interaction between the EMWs and the absorber. Additionally, the carbon network and embedded Fe 3 O 4 nanoparticles caused significant dielectric losses and magnetic losses, respectively, which also enhanced EMWA. The EMWA characteristics of the microspheres could be precisely tuned via changing the carbon content to achieve optimized impedance matching. Porous Fe 3 O 4 /C microspheres with a 71.5 wt% carbon content displayed particularly impressive EMWA properties: a maximum reflection loss (RL) value of − 31.75 across broad band frequencies in the range of 7.76–12.88 GHz (RL < −10 dB) at an absorber thickness of 3.0 mm. These excellent EMWA properties may be attributed to both dielectric loss (carbon) and magnetic loss (Fe 3 O 4). Additionally, the 3D interconnected porous structure of the Fe 3 O 4 /C microspheres is especially favorable for impedance matching. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]

There is a marked correlation between the composition, microstructure and properties in TiCN-based cermets. In the case of using iron alloys as metallic matrix the carbon content is of particular significance, as not only influences the stoichiometry of ceramic phase but also induces phase transformations in the steel matrix. However, such influence has been less studied in steel matrix cermets than in conventional Ni or Co ones, so the aim of this work is to contribute to the study of the influence of carbon content on the microstructure and properties of a steel matrix cermet containing fixed quantities of alloying elements. Samples were prepared by powder metallurgy and characterized combining different techniques as Transmission Mössbauer spectroscopy (TMS), X Ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), to explain differences found in hardness and toughness. [ABSTRACT FROM AUTHOR]

The changing carbon content of coal consumed in China between 2002 and 2012 is quantified using information from the power sector. The carbon content decreased by 7.7% over this interval, the decrease particularly pronounced between 2007 and 2009. Inferences with respect to the changing carbon content of coal and the oxidation rate for its consumption, combined with the recent information on coal use in China, are employed to evaluate the trend in emissions of CO 2 . Emissions are estimated to have increased by 158% between 2002 and 2012, from 3.9 Gt y-1 to 9.2 Gt y-1. Our estimated emissions for 2005 are notably consistent with data reported by China in its “Second National Communication” to the UN (NDRC, 2012) and significantly higher than the estimation published recently in Nature. The difference is attributed, among other factors, to the assumption of a constant carbon content of coal in the latter study. The results indicate that CO 2 emissions of China in 2005 reported by Second National Communication are more reliable to serve as the baseline for China's future carbon commitments (e.g. those in Paris Agreement of the UNFCCC). Discrepancies between national and provincial statistics on coal production and consumption are investigated and attributed primarily to anomalous reporting on interprovincial trade in four heavily industrialized provinces. [ABSTRACT FROM AUTHOR]

A numerical model for calculation of temperature and thermal stress in initial steel shell in plate and grooved slab continuous casting moulds was established to predict the influence of steel carbon content on the temperature and stress fields. The calculated results show that the temperature non-uniformity and surface stress of the initial shell increase as the steel temperature decreases. Among the steel grades with carbon contents of 0.06, 0.17, 0.45 and 0.80 wt-%, the initial shell surface stress of steel with 0.17 wt-% (peritectic steel) is the highest. In the grooved mould the temperature non-uniformity and surface stress of the initial shell are significantly lower than those in the plate mould. At 1.7 s after initial shell formation, the non-uniformity of shell surface temperature and stress in the grooved mould are four to nine times and three to nine times, respectively, lower than those in the plate mould. [ABSTRACT FROM AUTHOR]

The V-Ti-N microalloyed steel with a carbon content gradient was innovatively obtained through surface decarburization. Then, the effect of carbon contents on intragranular ferrite (IGF) formation was studied. With the carbon contents increasing from 0.39% to 0.47% (mass percent), the volume fraction of IGF decreases from 8.2% to 4.6%, but the number of IGF has no significant change. The critical size of IGF nuclei was calculated on the basis of classic heterogeneous nucleation theory. According to the results of calculation and statistics, with the carbon content increasing from 0.39% to 0.47%, the number of IGF nuclei does not decrease significantly. When the carbon content is relatively low, some (Ti, V)(C, N) particles precipitating in austenite matrix may also act as the nuclei of IGF to refine the pearlite-ferrite microstructure. [ABSTRACT FROM AUTHOR]

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The stress partitioning among ferrite, martensite and retained austenite, and the stability of retained austenite under uniaxial tensile loading of a TRIP-assisted multiphase steel are investigated using in-situ high-energy X-ray diffraction technique. The results indicate that the stress partitioning, mainly occurring in elastic and elastoplastic regions, is activated by the “stress feedback mechanism”. In the elastic region, the decline of increasing rate of ferrite stress is accompanied by the sudden increase of martensite and retained austenite stresses, which indicates a stress transfer from ferrite to martensite and retained austenite. During deformation, martensitic transformation first occurs in the retained austenite with low carbon content, followed by those with high carbon content, which is denominated “selective transformation mechanism”. In addition, the increment of average carbon content in retained austenite continuously increases with the gradual transformation of retained austenite into martensite. The evolution of retained austenite strain versus engineering stress is similar to that of martensite strain, except that austenite strain is higher than martensite strain at the end of uniform deformation, which is related to the high carbon content in retained austenite. [ABSTRACT FROM AUTHOR]

This study investigated the effects of carbon content on the tensile and low-cycle fatigue (LCF) properties of hydrogen-charged high-Mn steels. Fe-17Mn- x C ( x  = 0.5, 0.7, and 0.9 wt%) steels were electrochemically hydrogen-charged for this purpose. Interestingly, the carbon content gave rise to opposite hydrogen embrittlement (HE)-resistance trends between monotonic and cyclic loadings; with increasing carbon content, tensile properties deteriorated, while LCF life showed a positive correlation. Such differences were interpreted in terms of primary deformation mechanisms under each loading condition. Increasing carbon contents accompanied an increasing number of thin mechanical twins as well as a higher density of sessile dislocations in monotonic tensile deformation. However, stacking fault energy, which is closely related to carbon content, changed the slip mode during cyclic deformation, thus resulting in the opposing trends found in this work. [ABSTRACT FROM AUTHOR]

The increasing demand for high-performance steel alloys has led to development of transformation-induced plasticity (TRIP) and twinning-induced plasticity (TWIP) alloys over the past three decades. These alloys offer exceptional combinations of high tensile strength and ductility. Thus, the mechanical behavior of these alloys has been a subject of significant work in recent years. However, the challenge of economically providing Mn in the quantity and purity required by these alloys has received considerably less attention. To enable commercial implementation of ultrahigh-Mn alloys, it is desirable to lower the high material costs associated with their production. Therefore, the present work reviews Mn processing routes in the context of the chemical requirements of these alloys. The aim of this review is to assess the current state of the art regarding reduction of manganese ores and provide a comprehensive reference for researchers working to mitigate material processing costs associated with Mn production. The review is presented in two parts: Part 1 introduces TRIP and TWIP alloys, current industrial practice, and pertinent thermodynamic fundamentals; Part 2 addresses available literature regarding reduction of Mn ores and oxides, and seeks to identify opportunities for future process development. [ABSTRACT FROM AUTHOR]

Wrought iron containing 0.001%C was carburized in the intercritical temperature range between A3 and A1 and water quenched. During carburizing, a planar austenite-ferrite phase boundary migrates into the iron in this temperature range and the carbon content in the austenite at the boundary drops from 0.77% to 0% as the temperature rises from 727°C to 912°C. It is shown that the microstructure of the quenched austenite at the interface changes from martensite at the lower temperatures of the intercritical region to a bainite form at the higher temperatures. The cause of this change is discussed. Diffusion analysis is presented, showing reasonable agreement of case depths versus carburizing times. Metallographic evidence shows that carbon diffusion rates along ferrite/slag inclusions of the wrought iron far exceed either grain boundary diffusion or bulk diffusion rates. [ABSTRACT FROM AUTHOR]

The composite of low alloy steel reinforced with TiC particles (36 wt%) was prepared by the powder metallurgy (PM) process in this paper. The effects of the chromium content and the total carbon content on the composites were studied. The scanning electron microscopy (SEM) was used to observe the microstructure and such properties as porosity, hardness, transverse rupture strength (TRS) and fracture morphology of the samples were tested. The results show that the optimum sintering temperature decreases with the increase of chromium content. The porosity of sintered samples decreases with increasing the total carbon content, and increases with increasing the chromium content. The TRS and hardness of samples increase with the increase of the carbon content. With the increase of the chromium content, the TRS of the sample gradually decreases, and the hardness firstly increases and then decreases a little. This results from the combined effects of the martensite amount and the shape, size and composition of precipitated chromium carbides in the steel matrix. [ABSTRACT FROM AUTHOR]

The paper deals with hypereutectic high chromium cast irons. The subject of examination was the effect of various alloying elements (Ti, W, Mo, V) on the size of primary carbides and on the resultant material hardness. Using a scanning electron microscope with a wave dispersion analyser, the carbon content in carbides was established. To determine the other elements, an energy dispersion analyser was used. It was found that both the primary and the eutectic carbides were of the M7C3 type and very similar in composition. The carbides always contained Cr and Fe, and also W, Mo, V or Ti, in dependence on the alloying elements used. The structure of materials containing only chromium without any alloying additions exhibited coarse acicular primary carbides. The structure of materials alloyed with another element was always finer. Marked refinement was obtained by Ti alloying. [ABSTRACT FROM AUTHOR]

This paper describes the mechanism of a developed process--an integrated pyrolysis-tar decomposition process--to produce oil palm empty fruit bunch- (EFB-) derived biochar with additional solid carbon within the biochar bodies, produced by decomposition of tar vapor on its pore surface, using the chemical vapor infiltration (CVI) method. The product, carbon-infiltrated biochar, was characterized to investigate the possibility to be used as partial coke breeze replacement in ironmaking. Carboninfiltrated biochar is proposed to be utilized for a sintering process that could reduce the consumption of coke and CO2 emission in iron-steel industry. [ABSTRACT FROM AUTHOR]

The relationship between the carbon content of W1.4855 steel, and the parameters of heat treatment of solution quenching (maintaining time and maintaining temperature) is investigated. The obtained experimental data are used to perform a statistical processing, resulting in a regression equation, useful for predicting the remaining eutectic carbide content in W1.4855 steel as function of carbon content and heat treatment parameters. [ABSTRACT FROM AUTHOR]

Three sediment cores collected from GL-1, V-1(Vetehiya) and L-6 lakes of Schirmacher Oasis, East Antarctica were studied for sediment components (sand, silt, clay, total organic carbon, total nitrogen, TOC/TN ratio and biogenic silica), major elements (Aluminium, Iron and Manganese) and trace metals (Chromium, Zinc, Lead, Cobalt, Cadmium and Nickel). High sand content in all the three cores revealed the release of coarser sediments through mechanical weathering in fluvio-glacial environment. Relatively, high biogenic silica along with high total organic carbon associated with high clay in some sections indicated high primary productivity due to the warming and exposure of the lakes to the ice-melt water influx. TOC/TN ratio for all the cores was found to be < 10 which indicated that the major source of organic matter was autochthonous. Metals were found to be strongly associated with clay and organic carbon in core V-1, with sand and clay in core L-6 while, with silt and organic matter in core GL-1 indicating their role in regulating the distribution of metals. Cadmium in lake GL-1 was found to be associated with total organic carbon and showed largely biogenic origin, while, Cd and Pb in lakes L-6 and V-1 were found to be of anthropogenic origin. All the other metals showed signatures of lithogenic origin. [ABSTRACT FROM AUTHOR]

In the present study, the effect of the chemical and phase composition on the thermal properties of silicon oxide carbides (SiOC) has been investigated. Dense monolithic SiOC materials with various carbon contents were prepared and characterized with respect to their thermal expansion, as well as thermal conductivity. SiOC glass has been shown to exhibit low thermal expansion (e.g., ca. 3.2 × 10−6 K−1 for a SiOC sample free of segregated carbon) and thermal conductivity (ca. 1.5 W/(m∙K)). Furthermore, it has been observed that the phase separation, which typically occurs in SiOC exposed to temperatures beyond 1000–1200 °C, leads to a decrease of the thermal expansion (i.e., to 1.83 × 10−6 K−1 for the sample above); whereas the thermal conductivity increases upon phase separation (i.e., to ca. 1.7 W/(m∙K) for the sample mentioned above). Upon adjusting the amount of segregated carbon content in SiOC, its thermal expansion can be tuned; thus, SiOC glass ceramics with carbon contents larger than 10–15 vol % exhibit similar coefficients of thermal expansion to that of the SiOC glass. Increasing the carbon and SiC content in the studied SiOC glass ceramics leads to an increase in their thermal conductivity: SiOC with relatively large carbon and silicon carbides (SiC) volume fractions (i.e., 12–15 and 20–30 vol %, respectively) were shown to possess thermal conductivities in the range from 1.8 to 2.7 W/(m∙K). [ABSTRACT FROM AUTHOR]

The synthesis of mesoporous Mo 2 C/carbon catalysts by carbothermal hydrogen reduction is reported. Petroleum coke (petcoke) was activated with KOH at 800 °C to obtain high surface area microporous activated petcoke (APC; ~ 2000 m 2 /g). The APC was wet impregnated with ammonium heptamolybdate (AHM: 10 wt% Mo), dried and reduced in H 2 at temperatures from 400 to 800 °C, to yield Mo 2 C/APC catalysts. Increased reduction temperature increased the Mo 2 C yield and the mesoporous volume of the Mo 2 C/APC. At a reduction temperature of 750 °C the mesopore volume of the catalyst doubled compared to the APC support and accounted for 37% of the total pore volume. Maintaining the final CHR temperature for 90 min further increased the Mo 2 C yield and mesoporosity of the catalyst. The role of Mo 2 C in the catalytic hydrogenation of the APC and mesopore generation is demonstrated. The activity of the Mo 2 C/carbon catalysts in the hydrodeoxygenation of 4-methyl phenol increased with increased CHR temperature and catalyst mesoporosity. [ABSTRACT FROM AUTHOR]

In recent years, the rolling densification process has become increasingly widely used to strengthen powder metallurgy parts. The original composition of the rolled powder metallurgy blank has a significant effect on the rolling densification technology. The present work investigated the effects of different carbon contents (0 wt. %, 0.2 wt. %, 0.45 wt. %, and 0.8 wt. %) on the rolling densification. The selection of the raw materials in the surface rolling densification process was analyzed based on the pore condition, structure, hardness, and friction performance of the materials. The results show that the 0.8 wt. % carbon content of the surface rolling material can effectively improve the properties of iron-based powder metallurgy parts. The samples with 0.8 wt. % carbon have the highest surface hardness (340 HV0.1) and the lowest surface friction coefficient (0.35). Even if the dense layer depth is 1.13 mm, which is thinner than other samples with low carbon content, it also meets the requirements for powder metallurgy parts such as gears used in the auto industry. [ABSTRACT FROM AUTHOR]

The thermal power industry, the cement industry and the iron & steel industry are among the top energy consumers and air-polluters in China, which have significant impacts on climate change. The annual productions of these three industry sectors are all ranked as the top one in the world. In order to assist the short-term policy making for the development of critical LCTs in China, an evaluation of the performance of low carbon technologies (LCTs) for the top three energy-intensive industries in China is conducted in this paper through multi-criteria decision making (MCDM) method. There are 31 LCTs identified for these three industries based on the criteria including environmental performance, technological performance, and economic performance. Based on the experts’ evaluation, top 10 LCTs are selected as the critical LCTs which should be given priority in the short-term technology diffusion in China. Suggestions are provided for policy-makers on the carbon mitigation and cleaner production in the main energy-intensive industries in China. [ABSTRACT FROM AUTHOR]

Ti(C, N)-based cermets with different carbon content were prepared by vacuum sintering and gas pressure sintering (Ar, 20 MPa). Effects of carbon content and sintering method on the microstructure, composition and mechanical properties of cermets were studied. Results showed average grain size and thickness of rim phase to increase with higher carbon or by gas pressure sintering, which was caused by the accelerated dissolution-precipitation process. More uniform morphology with broadened grain size distribution was obtained by gas pressure sintering, leading to improved density and properties. Cermets with 0.8 wt%C showed the best mechanical properties, i.e. 2105 MPa (TRS), 10.55 MPa m 1/2 (K IC ), and 1581 (H V 10), although containing residue Ni 2 (W, Ti) 4 C. Further increasing the carbon addition leads to thick rims and high amount of white core-grey rim phases, which can deteriorate the properties. Adequate control of size and composition of the core-rim structure plays a key role in ensuring satisfactory mechanical properties. [ABSTRACT FROM AUTHOR]

This work aims to investigate the effects of pre-straining and microstructure on bake hardening (BH) response of dual phase (DP) steels. Four kinds of different grades of commercial DP steels, DP340/600, DP420/780, DP500/780 and DP550/980, were pre-strained in tension to 0.5%, 1%, 2%, 4%, 6% and 8%, then baked at 170 °C for 20 min followed by restraining, or just baked at 170, 190, 210, 230, 250 °C for 20 min and at 250 °C for 40 min followed by straining without pre-straining. Electron backscattered diffraction (EBSD) measurements and temperature-dependent internal friction measurements were conducted to characterize geometrically necessary dislocations (GNDs) and analyze solute carbon content and interactions between point defects and dislocations in DP steels. The results show that for all grades of DP steels investigated, BH values increase to peak values at pre-straining ranging from 0.5% to 2% and then decline with further pre-straining. At BH condition of 170 °C/20 min, peak BH values with pre-straining are 33 MPa for DP340/600, 34 MPa for DP420/780, 78 MPa for DP500/780 and 90 MPa for DP550/980 respectively. Pre-straining can cause increase in tensile strength and decrease in total elongation after baking, especially for DP500/780 and DP550/980. DP steels without pre-straining can reach very high BH 0 values by applying either higher temperature or longer holding time. Solute carbon content in ferrite controls the speed of BH response in DP steels. Microstructures of higher volume fraction of martensite, smaller martensite islands and smaller ferrite grains can produce higher BH values. [ABSTRACT FROM AUTHOR]

Here, we have systematically investigated how the nature of the support influenced the oxygen mobility and activities in catalysts comprised of AgPt nanoshells deposited over inorganic oxides. We first synthesized AgPt nanoshells by galvanic replacement reaction between Ag nanospheres and PtCl combined with Pt reduction using hydroquinone as an auxiliary reducing agent. The nanoshells were then supported over TiO, AlO and CeO. Through this methodology, we prepared materials with similar metallic nanoparticle AgPt compositions (~0.99 wt% Pt), sizes (43 ± 2 nm diameter), spherical shapes, surface morphologies, number of active sites $$ (\sim4.5\;\upmu{\text{mol}}\;{\text{g}}_{{{\text{cat}} .}}^{ - 1} ) $$ and uniform distribution over the supports, differing only in terms of the nature of the support. The oxide reduction temperature, its capability of re-oxidation and the presence of oxygen mobility were strongly dependent on the metal-support interaction between AgPt nanoshells and oxide supports. These properties have significantly influenced their catalytic performances toward the CO oxidation. At 230 °C, the CO oxidation TOF was 40.4 ± 0.4, 6.9 ± 1, 1.4 ± 0.8 min for AgPt/CeO, AgPt/TiO, AgPt/AlO, respectively. These differences were attributed to the concentration of oxygen vacancies in each catalyst, which presented exactly the same trend as that of the catalytic activities. Our results may have important contributions to the design of highly active metal oxide-based catalysts toward gas-phase oxidation transformations. [ABSTRACT FROM AUTHOR]

This paper compares data from various sources concerning the impact of high magnetic field (HMF) on changes that occur in pearlite with respect to microstructure, phase transition, and mechanical properties. HMF raises the transformation temperatures of both ferrite and pearlite. This effect can be enhanced by increasing the carbon content. Other alloying elements may influence austenite decomposition temperature, Curie temperature, and magnetic moment, thus either increasing or decreasing the effect of HMF on phase transformation temperature. By altering the transformation thermodynamics, HMF increases the volume fraction of proeutectoid ferrite, decreases that of cementite, and decreases the lamellar spacing. HMF introduces the microstructure anisotropy and aligns proeutectoid ferrite grains parallel to the direction of the HMF. This effect becomes smaller when the cooling rate is higher. By affecting both phase transformation and the alignment of grains, HMF affects the morphology and microstructure of proeutectic ferrite and pearlite, and, consequently, their mechanical properties and corrosion resistance. [ABSTRACT FROM AUTHOR]

The development of several novel multifunctional components to perform specific unique functions is directed towards meeting the demands for advanced components in industries. In this study, the role played by carbon (C) variation on the steel part composition of cemented tungsten carbide and steel bilayer processed via powder metallurgy was investigated. Microstructural examination through field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS) revealed the presence of detrimental eta carbide phase (MC) distributed across the interface of sintered bilayer compacts. A significant reduction of MC was observed with 0.8 wt.% C when interlayer diffusion was accelerated resulting in better morphology and higher hardness values of 735.70 and 150.97 kgf mm in WC and Fe layers, respectively. Tensile strength property was evaluated to examine the sintering compatibility and the interfacial bond strength of bilayer specimens. Excellent bond strength was achieved in all sintered bilayer with increasing C level and enhanced densification which consequently improved tensile strength by 19%. [ABSTRACT FROM AUTHOR]

Pressed WC-Co hardmetal compacts of two different compositions, 6 and 10 wt% Co, were heat treated under flowing atmospheres of nitrogen, hydrogen and methane at temperatures from 500 to 900 °C prior to sintering under argon. Microstructural examination showed excessive carburisation up to 2.5 mm into the compacts with regions most exposed to heat treatment atmospheres showing greatest carburisation. η-Phase was present in the 6 wt% Co samples heat treated at low temperatures without methane but was not present with heat treatment temperatures of 700 °C or above with methane present. The hardness of both materials was significantly lower in highly carburised regions, highlighting the need for careful control of heat treatment parameters. [ABSTRACT FROM AUTHOR]

Supported Ni catalysts are prepared by water impregnation, ammonia impregnation and ammonia impregnation combined with dielectric-barrier discharge (DBD) method. The catalyst prepared by the third method shows superior activity, excellent aiti-sintering and anti-coking performances at high temperature in CO methanation. For this catalyst X-ray powder diffraction and transmission electron microscopy reveal the high dispersion of Ni particles. High-resolution transmission electron microscopy shows special surface with more Ni(111). Temperature programmed reduction uncovers the strong metal-support interaction between Ni and SiO. This is mainly caused by the formation of nickel-containing phyllosilicate during ammonia impregnation and the controlled growth at lower temperature in subsequent process of DBD treatment. High dispersion of Ni particles leads to improved activity. Strong metal-support interaction suppresses the mobility of Ni particles, which further improves the anti-sintering performance of Ni/SiO. Small Ni particles with more Ni(111) facets inhibit carbon deposition. Hence, DBD method combined with ammonia impregnation is an effective way to enhance the activity and high temperature stability of Ni/SiO catalyst. [ABSTRACT FROM AUTHOR]

The as-quenched martensite crystal structure is widely accepted as body-centered tetragonal. The classical Honda & Nishiyama model, c/a = 1 + 0.045 wt%C, was obtained based only on the experimental results for steels containing more than 0.6 wt% of carbon. This model was used to predict that steels containing less than 0.6 wt% of carbon would follow the same relation. However, it was reported by Sherby that the steel with less than 0.6 wt% of carbon is body-centered cubic, and c/a ratio equals to 1. This debate is caused by highly overlapped martensite (002) and (200) peaks when the carbon content of steel is less than 0.6 wt%. In this paper, the martensite lattice parameters of the as-quenched steels with different carbon contents were measured using high-resolution X-ray diffractometer. Rietveld refinement was used to deconvolute overlapped martensite peaks. For the steel with less than 0.6 wt% of carbon, the structure is proved to be body-centered tetragonal. It was found that the relationship between c/a ratio and carbon content follows as c/a = 1 + 0.031 wt%C. [ABSTRACT FROM AUTHOR]

Carbon-wrapped MnO nanodendrites interspersed on reduced graphene oxide sheets (C-MnO/rGO) were prepared on nickel foam by a facile vacuum filtration and a subsequent thermal treatment. As a binder-free anode of lithium-ion battery, the nanodendritic structure of C-MnO accommodates the huge volume expansion and shortens the diffusion length for lithium ion and electron, rGO sheets prevent C-MnO nanodendites from aggregation and offer a good electronic conduction. As a result, the electrode with such a novel architecture delivers superior electrochemical properties including high reversible capacity, excellent rate capability and cycle stability. Moreover, MnO nanodendrites change to nanoparticles wrapped in graphene sheets during the lithiation/delithiation process, which is a more beneficial microstructure to further increase the specific capacity and cycle life of the electrode. [ABSTRACT FROM AUTHOR]

Novel functionally graded hardmetals comprise a low-Co hard surface layer and a tough core region containing lots of Co. They are fabricated by self-assembly during liquid-phase sintering due to Co drifts from the surface layer having a high carbon content towards the core region with a low carbon content. A new mechanism of the self-assembly of the functionally graded hardmetals is proposed and their superior properties are explained by examining WC-WC grain boundaries on the nano-level. [ABSTRACT FROM AUTHOR]

1The object of research is the structural lamellar graphite cast iron, where the carbon equivalent (Ceq) is in the range of (4,214-4,372) % and the carbon content (C) is in the range of (3,425-3,563) %. The aim of research is to describe the distribution of values of tensile strength of cast iron series in the factor space C-Ceq at a fixed level of Cr-Ni-Cu-Ti alloyed complex in narrow ranges. To achieve this aim, there are the next objectives. 1. Build a workable analytical description of the impact of the selected input variables on the tensile strength of cast iron. 2. Study the response surface and identify the most informative point of the factor space for further detailed investigation of the microstructure in these points. It is shown that polynomial regression equation provides forecast accuracy, exceeding the accuracy using a linear regression equation in 1,23 times. An existence of a saddle point is revealed on the basis of the canonical transformation of response surface. It is an informative indicator, which suggests that the respective values of the input variables C = 3,492 %, Ceq = 4,28 % when the content of alloying elements Cr ± 0,032 %, Cu ± 0,026 % form a microstructure that guarantees the value of cast iron tensile strength TS = 203 MPa. In view of the resulting confidence interval, this value with a probability of 95 % is in the range of TS = (193-213) MPa. Metallographic microstructure description in the saddle point is important and can be obtained by the development of modeling results. It is noted that there is a fundamental opportunity to improve accuracy and obtaining more precise description of the response surface - due to numerical building of D-optimal plan or artificial orthogona- lization of full factorial experiment, inside the considered in this work [ABSTRACT FROM AUTHOR]

Low-cost, single-step synthesis of hollow nanotubes of N-doped carbon deposited on CoS is enabled by the simultaneous use of three functionalities of polyacrylonitrite (PAN) nanofibers: 1) a substrate for loading active materials, 2) a sacrificial template for creating hollow tubular structures, and 3) a precursor for in situ nitrogen doping. The N-doped carbon in hollow tubes of CoS provides a high-capacity anode of long cycle life for a rechargeable Li-ion or Na-ion battery cell that undergoes the conversion reaction 2 A++2 e−+CoS →Co+A2S with A=Li or Na. [ABSTRACT FROM AUTHOR]

To clarify the effect of C addition on shape memory effect (SME) in Fe-Mn-Si-based alloys, the SME and microstructures of two Fe-Mn-Si-Cr-Ni alloys with different C contents had been studied after deformed between 293 K and 77 K. The results showed that the SME in the Fe-Mn-Si-based alloys can be significantly enhanced by the addition of more C when deformed at a proper temperature. A comparable recovery strain of 4.2% to that in the Fe-Mn-Si-based alloys subjected to special treatments was obtained in a solution treated Fe-16.99Mn-5.59Si-9.28Cr-5.67Ni-0.12 C alloy when deformed at 77 K. This significant improvement can be ascribed to the remarkably increased difference between the critical stress for the permanent slip and that for the stress-induced ε martensitic transformation due to the addition of more C. [ABSTRACT FROM AUTHOR]