Journal articles: 'Metal carbide'

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Penghui, Yang, Hanguang Fu, Lin Jian, Cheng Haiqiang, and Lei Yongping. "Experimental and ab initio study of the influence of a compound modifier on carbidic ductile iron." Metallurgical Research & Technology 116, no. 3 (2019): 306. http://dx.doi.org/10.1051/metal/2018124.

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To improve the morphology of carbides in carbidic ductile iron, a compound modifier consisting of 0.1% Nb + 0.1% Ti + 0.1 wt.% Y was added to the base ductile iron with chemical composition of 3.72% C, 2.77% Si, 0.51% Mn, 0.99% Cr and balance Fe (wt.%). The effect of this compound modifier on the microstructures of carbidic ductile iron was studied. Also, first-principles calculations were carried out to better understand the modification mechanisms. The results showed that the maximum diameter of spheroidal graphite nodules decreased from 58 to 34 µm after the addition of compound modifier, and continuous carbide networks changed into a broken network. The roundness of graphite nodules decreased slightly, and the percent nodularity of the graphite nodules and the number of carbides decreased by 3 and 1.8%, respectively. Compounds with higher melting point are formed thanks to the compound modifier which acts as heterogeneous core, and the remaining Ti and Nb elements can be selectively attracted by (010) surface of Fe8Cr4C4. Furthermore, Cr elements can be easily replaced by Ti and Nb in the carbides to form more stable Fe8Cr3TiC4 and Fe8Cr3NbC4, which can prevent the continuing growth of carbide on the Fe8Cr4C4 (010) crystal surface and break the continuous network M3C. Y atoms cannot be directly adsorbed onto Fe8Cr4C4 (010) surfaces. They combine first with oxygen in the ductile iron to form Y2O3. The work of adhesion of the interface between a Y2O3 (100) and a Fe8Cr4C3 (010) is predicted to be 0.3 J/m2. The addition of Y element is found to have a positive effect on breaking up the continuity of the carbide network.

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De Bonis, Angela, Mariangela Curcio, Antonio Santagata, Agostino Galasso, and Roberto Teghil. "Transition Metal Carbide Core/Shell Nanoparticles by Ultra-Short Laser Ablation in Liquid." Nanomaterials 10, no. 1 (January 14, 2020): 145. http://dx.doi.org/10.3390/nano10010145.

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Transition metal carbide nanoparticles are a class of technological interesting materials with a wide range of applications. Among metal carbides, tantalum carbides have good compatibility with the biological environment while molybdenum carbides are used as catalyst in electrochemical reactions. Laser ablation of bulk transition metal targets in some liquids is here reported and laser ablation in organic solvents is used as simple synthetic strategy for the production of carbide nanostructures. Herein, the nanoparticles produced by ultra-short laser ablation of tantalum and molybdenum in water, acetone, ethanol and toluene have been characterized by TEM, XRD and XPS analysis. The combined effect of metal and solvent chemical and physical properties on the composition of the nanomaterials obtained has been pointed out. In particular, the different reactivity of Ta and Mo with respect to oxidizing species determines the composition of particles obtained in water, on the other hand the organic solvents decomposition allows to obtain transition metal carbide (TMC) nanoparticles. The observed carbonaceous shell formed on TMC allows to protect the particle’s carbidic core and to improve and tailor the applications of these nanomaterials.

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He, Bao, Jing Li, Cheng-bin Shi, and Hao Wang. "Effect of Mg addition on carbides in H13 steel during electroslag remelting process." Metallurgical Research & Technology 115, no. 5 (2018): 501. http://dx.doi.org/10.1051/metal/2018071.

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The effect of Mg on carbides precipitation in H13 steel was studied based on the Thermo-Calc thermodynamic calculation. The results showed that the precipitation temperature of MC phase was significantly improved by adding Mg. The Mg addition had no effect on the type of precipitated carbides. The as-cast microstructure and the characteristic of carbides in Mg-containing H13 steel were analyzed by OM and SEM-EDS. The results showed that the segregation of as-cast microstructure was released and the size of carbides was reduced by increasing Mg. The distribution of carbides was more homogeneous. The formed MgO · Al2O3 arising from Mg treatment provided preferred nucleation site for TiN, which was the core of heterogeneous nucleation of carbides, resulted in decreasing the size of carbides. Furthermore, partial Mg would melt into the carbides, which would change the morphology of carbide and induce the formation of leaf-like carbides. The electron probe micro-analysis (EPMA) results showed that the segregation of V and Mo in H13 steel was inhibited by Mg, and the dissolved Mg in carbide promoted the heterogeneous nucleation of carbides.

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Guerra, Francisco Vapeani, Arnoldo Bedolla-Jacuinde, Jorge Zuno-Silva, Ignacio Mejia, Edgar Cardoso-Legorreta, and Alberto Arenas-Flores. "Effect of the simultaneous Ti and W addition on the microstructure and wear behavior of a high chromium white cast iron." Metallurgical Research & Technology 116, no. 6 (2019): 602. http://dx.doi.org/10.1051/metal/2019031.

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The present work analyzes the effect of 0.7%Ti and 1.7%W addition to a 17% chromium white iron in as-cast condition and after destabilization heat treatment. These alloys are commonly used in applications where a high abrasive wear resistance is required. For this reason, in addition to the characterization, a complementary wear test was performed. The alloys were characterized by optical and electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The simultaneous Ti and W addition promoted the (Ti,W)C primary carbides formation which grow in the early stages of solidification. These carbides were found well distributed in the iron matrix with an average hardness value of 2450 HV. Moreover, tungsten was found partially distributed in the different phases increasing the microhardness by solid solution and refining the eutectic carbide. These microstructural modifications resulted in the increase of the bulk hardness and abrasive wear resistance of the alloyed iron. After destabilization heat treatment, the carbide precipitation and the matrix transformation produced a secondary hardening reducing the wear losses. Based in the results of the present study, the simultaneous addition of these elements to promote the (Ti,W)C carbide formation during solidification represents an effective method to increase the hardness and wear resistance of these kind of alloys via small additions.

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Krutskii, Yuriy L., Tatiana M. Krutskaya, Tatiana S. Gudyma, Konstantin B. Gerasimov, Roman R. Khabirov, and Anna V. Mass. "Carbothermal and boron carbide reduction of oxides of some transition metals." MATEC Web of Conferences 340 (2021): 01040. http://dx.doi.org/10.1051/matecconf/202134001040.

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The study presents a possible mechanism to produce carbides and diborides of transition metals, such as titanium, vanadium, chromium and zirconium. The carbothermal synthesis of transition metal carbides has defined the direct dependence between the thermodynamic stability of oxides and the temperature range of the reduction onset (the stronger the oxide, the higher the value of the temperature is). It reaches 2000-2100, 1500-1600, 1300-1400 and 2100-2200°C for such carbides as TiC, VC0,88, Cr3C2 and ZrC respectively. The same dependence has not been found for the diborides of these metals. Optimum synthesis temperatures for all these compounds lie in the range of 1600-1700 °C. This viable method to produce transition metal carbides consists in the transfer of vaporous higher and lower oxides. Diborides preparation involves the transfer of oxides and boron vapors onto the surface of the carbon material with the subsequent chemical interaction. In the case of carbide-boron reduction of zirconium oxide in excess of boron carbide, the reaction product will be a composite material (B4C – ZrB2). The ceramics based on this composite possesses high performance properties.

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Sharin, P. P., M. P. Akimova, and S. P. Yakovleva. "Structural-Phase State of the Interphase Boundary at Thermal Diffusion Metallization of Diamond Grains by Cr and Ti." Materials Science Forum 992 (May 2020): 670–75. http://dx.doi.org/10.4028/www.scientific.net/msf.992.670.

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Structural-phase state of the diamond-metallized coating interphase boundary after thermal diffusion metallization of diamond grains by transition metals Cr, Ti were studied. Metallization were conducted under temperature-time mode corresponding to the sintering of cemented carbide matrices with Cu impregnation. The structural-phase state of the metallized coating and diamond-coating interphase boundary was studied by scanning electron microscopy, X-ray phase analysis and Raman spectroscopy. It was found that a thin continuous metal carbide coating chemically bonded to the diamond and consisting of the corresponding metal, their carbides and small amount of graphite phases is formed during thermal diffusion metallization of diamond by Cr and Ti under the conditions specified in the experiment. It was shown that graphite is formed not by a continuous layer, but in the form of local inclusions. This ensures a strong adhesion of the metallized coating to the diamond through the carbides of the corresponding metals. The results can be useful in the development of compositions and technological methods that provide an increased level of diamond retention in the matrices of tools based on cemented carbide powder mixtures.

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Weinberger, Christopher R., and Gregory B. Thompson. "The crystal structure and phase stability of the zeta phase in the group VB transition metal carbides: a computational investigation." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 75, no. 5 (September 20, 2019): 870–79. http://dx.doi.org/10.1107/s2052520619011302.

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The crystal structure and composition of the zeta phase in the group VB transition metal carbides are not completely understood despite decades of experimental studies. As such, the phase rarely appears on phase diagrams of the group VB transition metal carbides. There is currently renewed interest in this phase, as tantalum carbide composites exhibit high fracture toughness in the presence of this phase. This work extends the initial computational study using density functional theory of the phase stability of the zeta phase in the tantalum carbide system, where the tantalum carbide zeta-phase crystal structure and stability were determined, to the niobium and vanadium carbides. It is shown that the zeta phases in the three systems share the same crystal structure and it is an equilibrium phase at low temperatures. The carbon atom ordering in the three different phases is explored and it is demonstrated that the zeta phase in the tantalum carbides prefers to order carbon atoms differently than in the niobium and vanadium carbide zeta phases. Finally, the properties of this crystal are computed, including elastic constants, electronic densities of states and phonon dispersion curves, to illustrate that this crystal structure is similar to other transition metal carbides.

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Li, Qing, Guangxu Cheng, Mu Qin, Yafei Wang, and Zaoxiao Zhang. "Research on Carbide Characteristics and Their Influence on the Properties of Welding Joints for 2.25Cr1Mo0.25V Steel." Materials 14, no. 4 (February 13, 2021): 891. http://dx.doi.org/10.3390/ma14040891.

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The carbide characteristics of 2.25Cr1Mo0.25V steel have an extremely important influence on the mechanical properties of welding joints. In addition, hydrogen resistance behavior is crucial for steel applied in hydrogenation reactors. The carbide morphology was observed by scanning electron microscopy (SEM) and the carbide microstructure was characterized by transmission electron microscopy (TEM). Tensile and impact tests were carried out and the influence of carbides on properties was studied. A hydrogen diffusion test was carried out, and the hydrogen brittleness resistance of welding metal and base metal was studied by tensile testing of hydrogenated samples to evaluate the influence of hydrogen on the mechanical properties. The research results show that the strength of the welding metal was slightly higher and the Charpy impact value was significantly lower compared to the base metal. The hydrogen embrittlement resistance of the welding metal was stronger than that of the base metal. The presence of more carbides and inclusions was the main cause of the decreased impact property and hydrogen brittleness resistance of the welding metal. These conclusions have certain reference value for designing and manufacturing hydrogenation reactors.

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Wyzga, Piotr, Lucyna Jaworska, Piotr Putyra, Marcin Podsiadlo, and Jolanta Cyboron. "Characterization of Metal-Like Carbides-Graphene Composite Prepared by SPS Method." Key Engineering Materials 655 (July 2015): 87–91. http://dx.doi.org/10.4028/www.scientific.net/kem.655.87.

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High hardness, good thermal and electrical conductivity make carbides technologically important materials. The high melting temperature and low coefficients of self-diffusion make it difficult to obtain full dense material. In this paper the results of Spark Plasma Sintering (SPS) of transition metal carbides: NbC, TaC, TiC, ZrC, VC with the addition of graphene 10-20 nm x 14 microns in an amount of 2.5 mass % are presented. Powders were mixed in isopropyl alcohol in a planetary ball mill for 1h. The sintering processes was carried out at 2200°C at two different times: 5 and 30 min. Microstructure of the samples was analyzed using scanning electron microscopy. The measurements of density, Young's modulus hardness and electrical properties were carried out, also. The best properties were obtained for titanium carbide powder, sintered for 30 min. The most significant density increase of the sintered carbide–graphene composite by about 5.3% (depending on increasing sintering duration) was obtained for niobium carbide, while the smallest densities change for zirconium carbide.

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10

ZURER, PAMELA. "Caged Metal Carbide." Chemical & Engineering News 79, no. 4 (January 22, 2001): 16. http://dx.doi.org/10.1021/cen-v079n004.p016a.

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Zou, Xingli, Kai Zheng, Xionggang Lu, Qian Xu, and Zhongfu Zhou. "Solid oxide membrane-assisted controllable electrolytic fabrication of metal carbides in molten salt." Faraday Discussions 190 (2016): 53–69. http://dx.doi.org/10.1039/c5fd00221d.

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Silicon carbide (SiC), titanium carbide (TiC), zirconium carbide (ZrC), and tantalum carbide (TaC) have been electrochemically produced directly from their corresponding stoichiometric metal oxides/carbon (MO_x/C) precursors by electrodeoxidation in molten calcium chloride (CaCl₂). An assembled yttria stabilized zirconia solid oxide membrane (SOM)-based anode was employed to control the electrodeoxidation process. The SOM-assisted controllable electrochemical process was carried out in molten CaCl₂ at 1000 °C with a potential of 3.5 to 4.0 V. The reaction mechanism of the electrochemical production process and the characteristics of these produced metal carbides (MCs) were systematically investigated. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy analyses clearly identify that SiC, TiC, ZrC, and TaC carbides can be facilely fabricated. SiC carbide can be controlled to form a homogeneous nanowire structure, while the morphologies of TiC, ZrC, and TaC carbides exhibit porous nodular structures with micro/nanoscale particles. The complex chemical/electrochemical reaction processes including the compounding, electrodeoxidation, dissolution–electrodeposition, and in situ carbonization processes in molten CaCl₂ are also discussed. The present results preliminarily demonstrate that the molten salt-based SOM-assisted electrodeoxidation process has the potential to be used for the facile and controllable electrodeoxidation of MO_x/C precursors to micro/nanostructured MCs, which can potentially be used for various applications.

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Qiao, Gui-ying, Xiu-lin Han, Xiao-wei Chen, Xu Wang, Bo Liao, and Fu-ren Xiao. "Transformation of M/A Constituents during Tempering and Its Effects on Impact Toughness of Weld Metals for X80 Hot Bends." Advances in Materials Science and Engineering 2019 (July 17, 2019): 1–10. http://dx.doi.org/10.1155/2019/6429045.

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Impact toughness of the weld metal is one of the important factors affecting the quality of hot bends, which is strongly dependent on the microstructure transformation during hot bending and tempering. In this study, three kinds of weld metals with different Ni contents were selected, and then the effects of tempering temperature on the microstructure impact toughness of weld metals for hot bends were investigated by simulation conducted on a Gleeble-3500 thermal simulator. The results show that the nonmetallic inclusion particles in weld metals can become the nuclear core of acicular ferrite like in as-welded metal. So, the overlapping acicular ferrite microstructure is obtained in the weld metal after direct cooling from the reheating temperature. During tempering, the overlapping acicular ferrite microstructure is degenerated, and martensite/austenite (M/A) constituents in the acicular ferrite microstructure decompose into ferrites and carbides. The resulting carbide particles mainly distribute along the acicular ferrite grain boundaries. With the increase of the tempering temperature, the carbide particles coarsen, which decreases the impact toughness of the weld metal of hot bends. Addition of Ni to weld metals can refine the acicular ferrite and improve the impact toughness.

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Ahmad, Saba, Iffat Ashraf, Muhammad Adil Mansoor, Syed Rizwan, and Mudassir Iqbal. "An Overview of Recent Advances in the Synthesis and Applications of the Transition Metal Carbide Nanomaterials." Nanomaterials 11, no. 3 (March 18, 2021): 776. http://dx.doi.org/10.3390/nano11030776.

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Good stability and reproducibility are important factors in determining the place of any material in their respective field and these two factors also enable them to use in various applications. At present, transition metal carbides (TMCs) have high demand either in the two-dimensional (2D) form (MXene) or as nanocomposites, nanoparticles, carbide films, carbide nano-powder, and carbide nanofibers. They have shown good stability at high temperatures in different environments and also have the ability to show adequate reproducibility. Metal carbides have shown a broad spectrum of properties enabling them to engage the modern approach of multifacet material. Several ways have been routed to synthesize metal carbides in their various forms but few of those gain more attention due to their easy approach and better properties. TMCs find applications in various fields, such as catalysts, absorbents, bio-sensors, pesticides, electrogenerated chemiluminescence (ECL), anti-pollution and anti-bacterial agents, and in tumor detection. This article highlights some recent developments in the synthesis methods and applications of TMCs in various fields.

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Zhao, Lili, Chaoqun Chai, Wolfgang Petz, and Gernot Frenking. "Carbones and Carbon Atom as Ligands in Transition Metal Complexes." Molecules 25, no. 21 (October 26, 2020): 4943. http://dx.doi.org/10.3390/molecules25214943.

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This review summarizes experimental and theoretical studies of transition metal complexes with two types of novel metal-carbon bonds. One type features complexes with carbones CL2 as ligands, where the carbon(0) atom has two electron lone pairs which engage in double (σ and π) donation to the metal atom [M]⇇CL2. The second part of this review reports complexes which have a neutral carbon atom C as ligand. Carbido complexes with naked carbon atoms may be considered as endpoint of the series [M]-CR3 → [M]-CR2 → [M]-CR → [M]-C. This review includes some work on uranium and cerium complexes, but it does not present a complete coverage of actinide and lanthanide complexes with carbone or carbide ligands.

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Zhang, Fu, Wenkai Zheng, Yanfu Lu, Lavish Pabbi, Kazunori Fujisawa, Ana Laura Elías, Anna R. Binion, et al. "Superconductivity enhancement in phase-engineered molybdenum carbide/disulfide vertical heterostructures." Proceedings of the National Academy of Sciences 117, no. 33 (July 29, 2020): 19685–93. http://dx.doi.org/10.1073/pnas.2003422117.

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Stacking layers of atomically thin transition-metal carbides and two-dimensional (2D) semiconducting transition-metal dichalcogenides, could lead to nontrivial superconductivity and other unprecedented phenomena yet to be studied. In this work, superconducting α-phase thin molybdenum carbide flakes were first synthesized, and a subsequent sulfurization treatment induced the formation of vertical heterolayer systems consisting of different phases of molybdenum carbide—ranging from α to γ′ and γ phases—in conjunction with molybdenum sulfide layers. These transition-metal carbide/disulfide heterostructures exhibited critical superconducting temperatures as high as 6 K, higher than that of the starting single-phased α-Mo2C (4 K). We analyzed possible interface configurations to explain the observed moiré patterns resulting from the vertical heterostacks. Our density-functional theory (DFT) calculations indicate that epitaxial strain and moiré patterns lead to a higher interfacial density of states, which favors superconductivity. Such engineered heterostructures might allow the coupling of superconductivity to the topologically nontrivial surface states featured by transition-metal carbide phases composing these heterostructures potentially leading to unconventional superconductivity. Moreover, we envisage that our approach could also be generalized to other metal carbide and nitride systems that could exhibit high-temperature superconductivity.

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Lima, Maria Jose S., M. V. M. Souto, A. S. Souza, M. M. Karimi, F. E. S. Silva, Uilame Umbelino Gomes, and Carlson P. de Souza. "Synthesis of Nanostructured Tungsten Carbide (WC) from Ammonia Paratungstate-APT and its Characterization by XRD and Rietveld Refinement." Materials Science Forum 899 (July 2017): 31–35. http://dx.doi.org/10.4028/www.scientific.net/msf.899.31.

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The carbides of refractory metals like tungsten carbide (WC), tantalum carbide (TaC) and niobium carbide (NbC), has been extensively studied due to their applications in several areas of industry, because of their specific properties; such as high melting point, high hardness, wear resistance, oxidation resistance and good electrical conductivity. The tungsten carbide, particularly, is generally used at hardmetal industries due to its high hardness and wear resistance. New synthesis techniques have been developed to reduce the synthesis temperature of refractory metal carbides using more reactive precursors and gas-solid reactions for carbon reduction. The result is producing pure carbides suitable properties for production of high quality cemented carbides and more selective catalysts. In this work, pure and nanostructured WC was obtained from the ammonium paratungstate hydrate (APT), at low temperature and short reaction time. Hydrogen (H2) and methane (CH4) were used as a reducing gas and carbon source, respectively. The precursor and obtained product were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results obtained by diffraction of X-rays showed that complete reduction and carburization of APT have been took place resulted in pure WC formation. The average crystallite size was in nanometer order reaching values of approximately 20.8 nm and a surface area (BET) of 26.9 m2/g.

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Chen, Meng, Yufei Ma, Yanqiang Zhou, Changqing Liu, Yanlin Qin, Yanxiong Fang, Guoqing Guan, Xiumin Li, Zhaoshun Zhang, and Tiejun Wang. "Influence of Transition Metal on the Hydrogen Evolution Reaction over Nano-Molybdenum-Carbide Catalyst." Catalysts 8, no. 7 (July 22, 2018): 294. http://dx.doi.org/10.3390/catal8070294.

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The highly efficient electrochemical hydrogen evolution reaction (HER) provides a promising way to solve energy and environment problems. In this work, various transition metals (Fe, Co, Ni, Cu, Ag, and Pt) were selected to support on molybdenum carbides by a simple organic-inorganic precursor carburization process. X-ray diffraction (XRD) analysis results indicated that the β-Mo2C phase was formed in all metal-doped samples. X-ray photoelectron spectroscopy analysis indicated that the binding energy of Mo2+ species (Mo2C) shifted to a lower value after metal was doped on the molybdenum carbide surface. Comparing with pure β-Mo2C, the electrocatalytic activity for HER was improved by transition metal doping on the surface. Remarkably, the catalytic activity improvement was more obvious when Pt was doped on molybdenum carbide (2% Pt-Mo2C). The 2% Pt-Mo2C required a η10 of 79 mV, and outperformed that of pure β-Mo2C (η10 = 410 mV) and other transition metal doped molybdenum carbides, with a small Tafel slope (55 mV/dec) and a low onset overpotential (32 mV) in 0.5 M H2SO4. Also, the 2% Pt-Mo2C catalyst demonstrated a high stability for the HER in 0.5 M H2SO4. This work highlights a feasible strategy to explore efficient electrocatalysts with low cost via engineering on the composition and nanostructure.

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Helava, Heikki I., Evgeny N. Mokhov, Oleg A. Avdeev, Mark G. Ramm, Dmitri P. Litvin, Alexander V. Vasiliev, Alexander D. Roenkov, Sergey S. Nagalyuk, and Yuri N. Makarov. "Growth of Low-Defect SiC and AlN Crystals in Refractory Metal Crucibles." Materials Science Forum 740-742 (January 2013): 85–90. http://dx.doi.org/10.4028/www.scientific.net/msf.740-742.85.

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Recently the wide bandgap semiconductors, silicon carbide (SiC) and aluminum nitride (AlN), have acquired increased importance due to the unique properties that make them applicable to a variety of rapidly-emerging, diverse technologies. In order to meet the challenges posed by these applications the materials need to be manufactured with the highest possible quality, both structural and chemical, at increasingly lower cost. This requirement places rather extreme constraints on the crystal growth as the simultaneous goals of high quality and low cost are generally incompatible. Refractory metal carbide technology, particularly, tantalum carbide (TaC), was originally developed for application in highly corrosive and reactive environments. The SiC group of Prof Yuri A Vodakov (for example, [1]) at Karmon Ltd in St Petersburg, Russia was the first to study and utilize the properties of refractory metal carbides, first for the growth of SiC and later for the growth of AlN. We discuss how the refractory metal carbides can answer many of the problems of growing SiC and AlN in a relatively simple and low cost manner.

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Bober, Mariusz, Jacek Senkara, and Bogdan Wendler. "Persistence of the thin layers of transition metal carbides in contact with liquid NiBSi alloy." Welding Technology Review 93, no. 1 (February 27, 2021): 5–12. http://dx.doi.org/10.26628/wtr.v93i1.1128.

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The article presents the results of study on interaction between the liquid NiBSi alloy and solid, thin, micrometer-range layers of transition metal carbides of IVB - VIB groups of the periodic table. The reactive magnetron sputtering method was adopted to deposit of these layers on molybdenum substrates. Carbide layers are destroyed in contact with liquid alloy by dissolving, intensified by the penetration of the liquid along the coating - substrate interface. The strong interaction between liquid NiBSi and both the carbide ceramics and the refractory metal substrate was revealed. The effect intensity differs somewhat for both tested carbide groups: IVB (relatively fast) and VIB (less intense).

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Yan, Li, Gang Qin Shao, Z. Xiong, Xiao Liang Shi, Xing Long Duan, and T. G. Wang. "Properties of Carbide-Metal Cermets Prepared from Composite Powders by Direct Reduction and Carburization Process." Key Engineering Materials 368-372 (February 2008): 1099–103. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.1099.

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The transition-metal carbide cemented by metal has excellent combined properties. In this study, cermets were prepared by vacuum sintering from carbide-metal composite powders. The transition- metal oxides (Cr2O3, MoO3, V2O5, Nb2O5 and TiO2), cementing-metal oxides (Co3O4 and NiO), and carbon black were used as raw materials to pre-synthesize composite powders such as Cr3C2-Co, Mo2C-Co, VC-Co, NbC-Co and TiC-Ni, by a direct reduction and carburization process in vacuum. Results show that the participation of Co3O4 and NiO as well as the vacuum circumstance were greatly propitious to the carburization of transition-metal oxides into carbides. The carbothermal condition was greatly improved by the direct reduction and carburization process.

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Lan, Leilei, Xingce Fan, Yimeng Gao, Guoqun Li, Qi Hao, and Teng Qiu. "Plasmonic metal carbide SERS chips." Journal of Materials Chemistry C 8, no. 41 (2020): 14523–30. http://dx.doi.org/10.1039/d0tc03512b.

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Zykova, Anna P., Irina Kurzina, Dmitry V. Lychagin, Andrey V. Chumaevsky, Artem A. Kachaev, and Vladimir Andreevich Bataev. "Structural State, Phase Composition and Mechanical Properties of Wear-Resistant Cast Iron Modified by Ultrafine Powders." Advanced Materials Research 872 (December 2013): 84–88. http://dx.doi.org/10.4028/www.scientific.net/amr.872.84.

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The paper explores the effect of a modifier based on ultrafine powders of refractory metal oxides on the change of structural state, phase composition and mechanical properties of cast iron of ИЧХ28Н2 (Russian grade). It was shown that the modifier added to the melt does not change the phase composition of ferrite-austenitic matrix and carbides and is not carbide-forming. Material microstructure changes only due to the presence of a large amount of crystallization nuclei during the casting cooling. It was established that the modification increases the ultimate stress limit by 53%, plasticity by 10.7%, corrosion resistance by 15%, and leads to the reduction of friction factor and linear wear due to the decreasing of structural elements: carbide phase and austenitic-carbidic eutectic.

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Gezerman, Ahmet Ozan, and Burcu Didem Çorbacıoğlu. "Effects of Mechanical Alloying on Sintering Behavior of Tungsten Carbide-Cobalt Hard Metal System." Advances in Materials Science and Engineering 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/8175034.

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During the last few years, efforts have been made to improve the properties of tungsten carbides (WCs) by preparing composite materials. In this study, we prepared WC particles by mechanical alloying and investigated the effects of mechanical alloying conditions, such as mechanical alloying time and mechanically alloyed powder ratio, on the properties of 94WC-6Co. According to experimental studies, increasing the mechanical alloying time causes an increase in the density of tungsten carbide samples and a decrease of crystal sizes and inner strength of the prepared materials. With the increase of mechanical alloying time, fine particle concentrations of tungsten carbide samples have increased. It is observed that increasing the mechanical alloying time caused a decrease of the particle surface area of tungsten carbide samples. Besides, the amount of specific phases such as Co3W3C and Co6W6C increases with increasing mechanical alloying time. As another subject of this study, increasing the concentration of mechanically alloyed tungsten carbides caused an increase in the densities of final tungsten carbide materials. With the concentrations of mechanically alloyed materials, the occurrence of Co6W6C and Co3W3C phases and the increase of crystallization are observed.

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Zhang, Yuanheng, Kai Ding, Guanzhi Wu, Bingge Zhao, Yuanfang Wang, Tao Wei, and Yulai Gao. "Aging-induced formation of the nano-sized clustered carbides in the weld metal of Co-based alloy/AISI 410 stainless steel dissimilar welded joint." Metallurgical Research & Technology 117, no. 4 (2020): 402. http://dx.doi.org/10.1051/metal/2020033.

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The microstructure evolution in Co-based alloy/AISI 410 stainless steel dissimilar welded joints by aging at 566 °C for 200, 400, 600, and 800 h was systematically investigated. In particular, the specimen aging treated for 800 h was emphasized in the present study for its nano-sized clustered characteristic microstructure. The results showed that the microstructure of the weld metal (WM) was mainly γ-Co matrix with dendritic morphology. Before aging treatment, the elements Cr and W segregated slightly in the interdendritic regions. Nevertheless, a large amount of nano-sized clustered carbides rich in elements Cr and W precipitated along grain boundaries after aging treatment. The element segregation during solidification and element diffusion under high-temperature condition could trigger the carbide formation. Though the precipitated carbides revealed a negligible influence on the microhardness of weld (∼ 275 HV), yet a stable performance under high-temperature condition was anticipated for this weldment considering the grain boundary strengthening effect of the nano-sized carbides.

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Reinholdt, Anders, Konrad Herbst, and Jesper Bendix. "Delivering carbide ligands to sulfide-rich clusters." Chemical Communications 52, no. 10 (2016): 2015–18. http://dx.doi.org/10.1039/c5cc08918b.

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The propensity of the terminal ruthenium carbide Ru(C)Cl₂(PCy₃)₂ (RuC) to form carbide bridges to electron-rich transition metals enables synthetic routes to metal clusters with coexisting carbide and sulfide ligands.

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Makarov, Yu N., D. Litvin, A. Vasiliev, and S. Nagalyuk. "Sublimation Growth of 4 and 6 Inch 4H-SiC Low Defect Bulk Crystals in Ta (TaC) Crucibles." Materials Science Forum 858 (May 2016): 101–4. http://dx.doi.org/10.4028/www.scientific.net/msf.858.101.

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Recently, the wide bandgap semiconductors, especially silicon carbide (SiC), have become more important due to the unique electrical and thermophysical properties that make them applicable to a variety of electronic devices (Schottky and PiN diodes, JFETs, MOSFETs, etc.). For these applications, the crystals need to be manufactured with highest possible quality, both structural and chemical, at reduced cost. This requirement places rather extreme constraints on the crystal growth as the simultaneous goals of high quality and low cost are generally incompatible.Refractory metal carbide technology, particularly, tantalum carbide (TaC), was originally developed for application in highly corrosive and reactive environments. Yu. Vodakov [1] demonstrated for the first time advantages of use of refractory metal carbides for PVT growth of SiC and later AlN bulk crystals. In the present paper we discuss the effect of refractory metal on PVT growth of large diameter 4H SiC bulk crystals.

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Tarraste, Marek, Jakob Kübarsepp, Kristjan Juhani, Märt Kolnes, and Mart Viljus. "High Energy Milling of WС-FeСr Cemented Carbide." Key Engineering Materials 799 (April 2019): 136–41. http://dx.doi.org/10.4028/www.scientific.net/kem.799.136.

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During production of cemented carbides hard and brittle tungsten carbide (WC) and ductile metal powders (mainly from Fe-group) are milled together. Complete milling results in a Gaussian distribution and narrow particle size range of the milled powder which promote the homogeneity and improve the properties of sintered composites. Cobalt, conventional metal employed in cemented carbides, possesses good comminution characteristics with WC powder. However, its toxicity and fluctuating price pushes researchers to find suitable alternatives and Fe-based alloys have shown most promising results. Cemented carbides with the Fe-Cr system as metal binder phase have potential to perform better than regular WC-Co composites in corrosive and oxidative environments. The goal of this paper was to prepare uniform cemented carbides powders with relatively high fraction of stainless Fe-Cr steel. To achieve a uniform powder mixture is a challenge at high ductile steel fraction. High energy milling (HEM) is a powerful technique for achieving (ultra) fine powder mixtures with narrow powder size range. HEM was carried out in a novel high energy ball mill RETSCH Emax. Milling in tumbling ball mill, which is the most widely used method, was employed for reference. Prepared powder mixtures were characterised in terms of particle size, size distribution and shape. In addition, powder mixtures were consolidated via spark plasma sintering to evaluate the effect of the milling method and the duration on the microstructure of final cemented carbide.

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Su, Qing Cai, Jian Hua Zhang, Long Wei Yin, and Mu Sen Li. "The Research on Microstructure of Catalyst and Growth Mechanism of Boron-Doped Diamond." Advanced Materials Research 399-401 (November 2011): 1147–50. http://dx.doi.org/10.4028/www.scientific.net/amr.399-401.1147.

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The microstructure of catalyst discs and fracture topography of boron-doped diamond blocks are analyzed in this paper. The results show that boron can promote or inhibit the growth of diamond crystal. The battens of metal carbides in catalyst are the main carbon source in the nucleation and growth of diamond. Crystal nucleus can absorb the carbon atoms from metal carbide in catalyst disc, and continually grow. It is resulted that the carbon atoms around the diamond grains in catalyst disc reduce, and the battens of metal carbides are thin. The more diamond grains are produced, the thinner battens of metal carbides in catalyst disc are formed.

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Zhang, Yuan Bin, Hui Luo, and Guo Fan Wang. "The Effect of the Microstructure on the Wear-Resistance in the Welding Deposited Metal." Key Engineering Materials 353-358 (September 2007): 766–69. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.766.

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The microstructure and wear-resistance of the welding deposited metal of Fe-Ti-Nb-V-C and Fe-Cr-W-Mo-C alloy system (with American MG700 as example) are studyed by using SEM , TEM and MM200 wear testing machine. It is revealed that Ti and Nb promote the formation of dispersed MC type carbide granules, while the carbides of Cr and W or Mo tend to precipitate along grain boundary. The formation of MC carbide granules depletes the carbon content in the matrix, and then low carbon martensite matrix can be achieved. The hard and tough matrix and the granular carbides improve the wear-resistance of the deposited metal. But excessive Ti and Nb induce the formation of bigger granules with sharp corner and result too soft matrix, then the wear-resistance decrease. As to the Fe-Cr-W-Mo-C alloy system, network carbides and high carbon martensite matrix make the deposited metal very brittle. During wearing process, the propagating of microcrack in the matrix induces lots of scraps flake off, which decrease the wear-resistance of the deposited metal. The deposited metal of Fe-0.64Ti-1.18Nb-2.18V-1.43Cr-0.97C alloy system in current study achieve the best wear-resistance.

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30

Waki, T., S. Terazawa, Y. Umemoto, Y. Tabata, K. Sato, A. Kondo, K. Kindo, and H. Nakamura. "Metamagnetism of η-carbide-type transition-metal carbides and nitrides." Journal of Physics: Conference Series 320 (September 28, 2011): 012069. http://dx.doi.org/10.1088/1742-6596/320/1/012069.

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31

Носенко, Владимир, Vladimir Nosenko, Александр Фетисов, Alexander Fetisov, С. Носенко, S. Nosenko, Валентин Харламов, and Valentin Kharlamov. "Contact interaction intensity and material transfer at grinding and refractory metal micro-scratching." Science intensive technologies in mechanical engineering 2, no. 10 (October 4, 2017): 9–18. http://dx.doi.org/10.12737/article_59d496eb7ba532.91441180.

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Peculiarities in the contact surfaces formation and material transfer at micro-scratching and grinding of refractory metals are investigated. There is shown a connection of metal quantity transferred to the area of crystal wear, a degree of ground surface charging with silicon carbide crystals and wear of an abrasive tool with the electron structure of atoms in refractory metals. It is defined, that the intensity of metal transfer in a crystal surface layer decreases with the increase of a principle quantum number of metal valence electrons. According to the intensity of the interaction silicon carbide during grinding and micro-cutting the refractory metals are classified into adhesion-active metals of IVB, VB sub-groups and inert metals of VIB subgroup of the Periodic Table.

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32

Lu, Hao, Chong Zhao, Haibin Wang, Xuemei Liu, Rong Yu, and Xiaoyan Song. "Hardening tungsten carbide by alloying elements with high work function." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 75, no. 6 (November 8, 2019): 994–1002. http://dx.doi.org/10.1107/s2052520619012277.

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There is intensive searching for superhard materials in both theoretical and experimental studies. Refractory and transition metal carbides are typical materials with high hardness. In this study, first-principles calculations were performed first to analyze the electronic structures and mechanical properties of the tungsten-carbide-based compounds. The results indicated that tungsten carbide could be hardened by alloying elements with high work functions to tailor the Fermi level and electron density. Guided by the calculations, a new type of tungsten carbide alloyed with Re was synthesized. The Young's modulus and hardness of the Re-alloyed tungsten carbide are increased by 31% and 44%, respectively, as compared with those of tungsten carbide. This study provides a new methodology to design superhard materials on a feasible electronic base using work function as a simple guiding parameter.

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Radev, Dimitar D. "Pressureless Sintering of Boron Carbide-Based Superhard Materials." Solid State Phenomena 159 (January 2010): 145–48. http://dx.doi.org/10.4028/www.scientific.net/ssp.159.145.

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Boron carbide-based materials B4C-MexBy were densified by pressureless sintering in a vacuum furnace. Some transition metal carbides (TiC, ZrC, HfC, Cr3C2 and WC) from groups IV-VI were used as sintering aids. The optimal sintering temperature in the range 2220-2250oC was used for any composition. Here we show the possibilities to activate the mass transport of the B4C by the mechanism of liquid phase sintering. The method of reactive sintering of B4C in the presence of additives of some transition metal carbides allows in situ synthesis of dense B4C-MexBy materials. Structural properties and fracture toughness of the B4C-based composite materials were discussed. The properties of some of these materials and the possibilities for their application are also discussed.

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34

Makota, Oksana, and Lidiya Bulgakova. "The Influence of Metal Carbides on the Oxidation Processes of 1-Octene by Molecular Oxygen and tert-Butyl Hydroperoxide." ISRN Physical Chemistry 2012 (January 9, 2012): 1–4. http://dx.doi.org/10.5402/2012/135028.

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The influence of metal carbides, TiC, VC, ZrC, Mo2C, TaC, and WC, on the liquid-phase oxidation processes of 1-octene by molecular oxygen and tert-butyl hydroperoxide was investigated. It was established that vanadium carbide is the most active in the oxidation process of 1-octene by molecular oxygen as well as in the tert-butyl hydroperoxide unproductive decomposition process in the hydroperoxide oxidation reaction. It was shown that there is a correlation among the activities of metal carbides in these processes.

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35

Krstic, V. D., and M. D. Vlajic. "Metal Free Tungsten Carbide Ceramics." Powder Metallurgy 41, no. 4 (January 1998): 239. http://dx.doi.org/10.1179/pom.1998.41.4.239.

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36

Moustakas, T. D., J. Scanlon, J. Y. Koo, H. W. Deckman, A. Ozekcin, R. Friedman, and J. A. McHenry. "Tungsten carbide-transition metal multilayers." Materials Science and Engineering: B 6, no. 2-3 (June 1990): 179–89. http://dx.doi.org/10.1016/0921-5107(90)90094-r.

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37

García, G., O. Guillén-Villafuerte, J. L. Rodríguez, M. C. Arévalo, and E. Pastor. "Electrocatalysis on metal carbide materials." International Journal of Hydrogen Energy 41, no. 43 (November 2016): 19664–73. http://dx.doi.org/10.1016/j.ijhydene.2016.04.146.

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38

Korzhov, V. P. "Carbide Coatings on Metal Ribbons." Bulletin of the Russian Academy of Sciences: Physics 85, no. 7 (July 2021): 798–802. http://dx.doi.org/10.3103/s106287382107011x.

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39

Cherchneff, Isabelle, and Piero Cau. "The chemistry of carbon dust formation." Symposium - International Astronomical Union 191 (1999): 251–60. http://dx.doi.org/10.1017/s0074180900203148.

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We shall review the various types of chemistry involved in the formation of carbonaceous material present in carbon-rich AGB stars, mainly amorphous carbon, silicon carbide and other metal carbides discovered in pre-solar Stardust extracted from meteorites. The chemistry is discussed in the context of laboratory experiments and their application to circumstellar AGB winds. Emphasis is put on polycyclic aromatic hydrocarbons (PAHs), titanium carbide clusters and silicon carbide grains. Attempt to explain the condensation sequences derived from the study of pre-solar grains of meteoretical origin is made on the basis of physio-chemical models which describe the periodically shocked gas close to the photosphere of AGB stars.

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Gubernat, Agnieszka. "Description of Carbides Sintering Process Using Kuczynski and Frenkel Sintering Models." Advances in Science and Technology 62 (October 2010): 209–14. http://dx.doi.org/10.4028/www.scientific.net/ast.62.209.

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This work presents measurements concerning sintering description according to two the: Kuczynski and Frenkel models. Investigation covered selected metal–like carbides: TiC0,8, NbC and WC. Kinetic equations were also developed, according to Kuczynski model to describe sintering of each carbide and it was attempted to determine mechanisms of mass transport mechanism dominating at each sintering stage. Parameters describing sintering process of each of investigated carbides: α and β constants, the initial shrinkage rate α-1, the limit of shrinkage at infinite time β-1 and initial apparent viscosity of system were in turn determined using Frenkel model. Such data allowed to achieve full characterization of carbide sintering.

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41

Kamysbayev, Vladislav, Alexander S. Filatov, Huicheng Hu, Xue Rui, Francisco Lagunas, Di Wang, Robert F. Klie, and Dmitri V. Talapin. "Covalent surface modifications and superconductivity of two-dimensional metal carbide MXenes." Science 369, no. 6506 (July 2, 2020): 979–83. http://dx.doi.org/10.1126/science.aba8311.

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Versatile chemical transformations of surface functional groups in two-dimensional transition-metal carbides (MXenes) open up a previously unexplored design space for this broad class of functional materials. We introduce a general strategy to install and remove surface groups by performing substitution and elimination reactions in molten inorganic salts. Successful synthesis of MXenes with oxygen, imido, sulfur, chlorine, selenium, bromine, and tellurium surface terminations, as well as bare MXenes (no surface termination), was demonstrated. These MXenes show distinctive structural and electronic properties. For example, the surface groups control interatomic distances in the MXene lattice, and Tin+1Cn (n = 1, 2) MXenes terminated with telluride (Te2−) ligands show a giant (>18%) in-plane lattice expansion compared with the unstrained titanium carbide lattice. The surface groups also control superconductivity of niobium carbide MXenes.

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42

LI, LINYAN. "FIRST PRINCIPLE CALCULATIONS OF A FAMILY OF NOBLE METAL NITRIDES AND CARBIDES." Modern Physics Letters B 22, no. 30 (December 10, 2008): 2937–44. http://dx.doi.org/10.1142/s0217984908017424.

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The structural and electronic properties of selected noble metal nitrides and carbides are studied using the local density approximation and the generalized gradient approximation. The zinc-blende and rock-salt structures are employed. The nitride and carbide of palladium have high bulk modulus. From the DOS, the MX ( M = Pd , Ag , Au ; X = N , C ) compound display metallic nature.

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43

Sil'chenko, Ol'ga, Marina Siluyanova, and Petr Hopin. "MICRO-HARDNESS AND WEAR-RESISTANCE INVESTIGATION IN CARBO-METAL COATING COMPOSITES OBTAINED THROUGH GAS-DETONATION METHOD." Bulletin of Bryansk state technical university 2020, no. 10 (October 11, 2020): 29–36. http://dx.doi.org/10.30987/1999-8775-2020-10-29-36.

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The work purpose consists in the investigation of carbometal coatings wear-resistance and micro-hardness depending on chemical structure of their components. The investigation object is carbide-metal coatings. The result analysis of comparative wear-resistance tests witnesses that with micro-hardness increase in metal carbides of compositions: Cr3C2, WC, TiC, TiCN, at a constant content of cladding metal (30…35mass %), a value of wear decreases according to the linear law. Wear intensity of coatings of clad carbide mixtures with different materials is defined to a certain extent with wear intensity of material added to the matrix. In the course of the work there were developed coating compositions reinforced with quasi-crystals, there is defined an optimum composition and modes of coating application with the gas-detonation method and their wear-resistance and micro-hardness were investigated.

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Briones-Rodríguez, C., Vicente Mayagoitia, and Ricardo Cuenca-Alvarez. "Dry Coated Particle for Plasma Spraying." Materials Science Forum 534-536 (January 2007): 37–40. http://dx.doi.org/10.4028/www.scientific.net/msf.534-536.37.

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The performance of an in-house designed mechanofusion process and the preparation of composite powders for plasma spraying are investigated in a variety of powdered mixtures including metal/oxide, carbide/oxide, carbide/metal and metal/oxide/carbide. Scanning electron microscopy shows that dry particle coating depends on the thermo-mechanical and chemical properties of the powdered system. In the metal/oxide, carbide/oxide and metal/oxide/carbide powder mixtures, fine ceramic particles coat the surface of the metallic or ceramic coarser particles with no need of binders or solvents. However with the carbide/metal powdered system, an intimate mixture of components is achieved with an incipient dry particle coating. A nearly rounded shape of the final composite particles is induced by the mechanical energy input with no formation of new phases as confirmed by XRD analysis. It is suggested that the coating mechanism is governed by agglomeration and rolling phenomena. Finally these types of powders feature characteristics to be plasma sprayed in air.

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45

Chaus, Alexander S., J. Chovanec, and M. Legerská. "Development of High-Speed Steels for Cast Metal-Cutting Tools." Solid State Phenomena 113 (June 2006): 559–64. http://dx.doi.org/10.4028/www.scientific.net/ssp.113.559.

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As-cast high-speed steels heat-treated have completely much lower impact toughness than that of the steels of a similar chemical composition but undergone hot working – rolling or forging. That is attributed to the influence of eutectic carbides, which especially being coarse, provide easily brittle intergrain fracture sites under low stress intensity factor levels. This is especially real for cast cutting tools. In order to exhibit good all-round performance the impact toughness enhancement of as-cast high-speed steels is obligatorily needed. In this connection it is expedient to turn from high-speed steels of conventional ledeburitic origin to high-speed steels of hypereutectoid and ferritic-carbidic ones with considerably lower carbide heterogeneity resulting in enhanced impact toughness. In the present work special features of the structure, phase composition and properties of such high-speed steels designed for cast tool are studied. In order to substitute tungsten by chromium in as-cast high-speed steel a special alloying system has also been developed.

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46

Ashok kumar, R., G. R. Raghav, K. J. Nagarajan, Sathish Rengarajan, P. Suganthi, and V. Vignesh. "Effect of hybrid reinforcement at stirred zone of dissimilar aluminium alloys during friction stir welding." Metallurgical Research & Technology 116, no. 6 (2019): 631. http://dx.doi.org/10.1051/metal/2019062.

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The main objective of this work is to modify the mechanical as well as surface properties of weld nugget by the reinforcement of hybrid ceramic particles (alumina and silicon carbide). This is accomplished by combining friction stir welding (FSW) and friction stir processing (FSP) on dissimilar AA6101-T6 and AA1350 aluminium alloys. For this purpose, various levels of mixing proportions of Al2O3 & SiC particles are used with constant groove depth and width i.e. constant groove dimension. To evaluate the quality of joints, tensile, bending, micro-hardness, wear and microstructural studies are carried out. Among these, reinforcement of 100% alumina particles exhibits better mechanical and wear properties. On the other hand, reinforcement of 100% silicon carbide particles produces poor mechanical and wear properties. And also increment in percentage of reinforcement of alumina particles improves the mechanical and wear properties of weld nugget, when compared to increment in percentage of reinforcement of silicon carbide particles.

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Shishkovsky, Igor, and Vladimir Scherbakov. "Selective Laser Fusion of Titanium Based Gradient Alloy Reinforced by Nano Sized TiC Ceramic." Materials Science Forum 916 (March 2018): 85–90. http://dx.doi.org/10.4028/www.scientific.net/msf.916.85.

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The surface improvement of light-weighted metals by adding of hard ceramic particles into a metal matrix has promised to be perspectives for aerospace industry. In the present study, titanium carbides of nano size were incorporated to the titanium substrate by a selective laser melting (SLM) of Ti + (10, 15 and 20 wt.%) TiC powder mixtures via an Ytterbium fiber laser with 1.075 mm wavelength. Optimal regimes of the 3D laser additive process were determined. We studied how the interfacial properties would change due to the difference in composition in case of the titanium matrix nano composites (TMNC) reinforced with carbides. The phase analysis of the fabricated TMNC showed that the initial carbide particles are dissolved after the remelting with different velocities. A particular attention was paid to the carbide dilution and secondary carbides formation mechanisms when the TiC was mixed with titanium. Various parameters, such as microstructure, phase constitution and mechanical properties of the gradient TMNCs were investigated by means of OM, SEM, XRD and microhardness measurement. It was shown that the microstructure had two types of heterogeneity: the TiC particles at the interlayer interfaces and element chemical segregation on the boundaries of the tracks.

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48

Amigó, Vicente, J. J. Candel, and P. Franconetti. "Titanium Metal Matrix Composite Laser Coatings Based on Carbides." Materials Science Forum 727-728 (August 2012): 299–304. http://dx.doi.org/10.4028/www.scientific.net/msf.727-728.299.

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Laser cladding is an adequate technique to fabricate Metal Matrix Composite (MMC) layers because of its focused high energy which allows the partial melting of hard ceramic reinforces particles like carbides. Thus, the wettability and gradual transition between metal and particle can be improved. However, metastable or new intermetallic phases can be formed during laser processing due to severe thermal cycle imposed to the clad with unknown properties in some cases. In this work our experience on microstructural analysis of Ti-MMC coatings acquired during the last five years is summarized. Special attention is paid on carbide dilution and secondary carbides formation mechanisms when TiC, SiC, Cr3C2, WC and B4C are mixed with titanium alloys.

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Nosenko, Vladimir A., Aleksandr V. Fetisov, Sergey V. Nosenko, Viktor G. Karpov, and Valeria E. Puzyrkova. "Study of the Silicon Carbide Wear Area after Micro-Scratching of Titanium, Zirconium, Niobium and Molybdenum at a Speed of 35 m/s." Materials Science Forum 1037 (July 6, 2021): 614–25. http://dx.doi.org/10.4028/www.scientific.net/msf.1037.614.

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The authors conducted the study at micro-scratching of titanium, zirconium, niobium and molybdenum alloys. The content of the main element in alloys was from 99.5 to 99.7 %. Micro-cutting was carried out by specially prepared indenters with silicon carbide mono-crystals of a given shape. The state of the relief and the chemical composition of the wear area were studied using a scanning two-beam electron microscope. The micro-scratching speed was 35 m/s without cooling. The condition of the contact surfaces of silicon carbide and metals was studied at a magnification up to 100,000 times with the rotation and tilt of the microscope slide. The content of chemical elements was determined at individual spots of an object by scanning along the line and area. The authors also studied the condition of the wear area after micro-scratching of metals and after removal of metal adhesions by chemical etching. The intensity of metal transfer was determined by the average concentration of metal atoms at the wear area. The article also gives a classification of metals according to the intensity of transfer immediately after grinding and removal of metal adhesions. The influence of metal and the depth of micro-scratching on the morphology of the wear site is shown. It was found that molybdenum, having a low adhesive activity to silicon carbide, is able to penetrate microcracks and other surface defects during micro-scratching. The width of microcracks and the depth of metal penetration were determined

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Tišler, Zdeněk, Romana Velvarská, Lenka Skuhrovcová, Lenka Pelíšková, and Uliana Akhmetzyanova. "Key Role of Precursor Nature in Phase Composition of Supported Molybdenum Carbides and Nitrides." Materials 12, no. 3 (January 29, 2019): 415. http://dx.doi.org/10.3390/ma12030415.

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In this work, we studied the effect of molybdenum precursors and the synthesis conditions on the final phase composition of bulk and supported molybdenum carbides and nitrides. Ammonium heptamolybdate, its mixture with hexamethylenetetramine, and their complex were used as the precursors at different temperatures. It was investigated that the synthesis of the target molybdenum nitrides strongly depended on the structure of the precursor and temperature conditions, while the synthesis of carbide samples always led to the target phase composition. Unlike the carbide samples, where the α-Mo2C phase was predominant, the mixture of β-Mo2N, MoO2 with a small amount of metal molybdenum was generally formed during the nitridation. All supported samples showed a very good dispersion of the carbide or nitride phases.

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Journal articles on the topic 'Metal carbide'

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