Carbide Content Research Articles

Improving electrochemical corrosion resistance of AISI 304 using tungsten carbide-cobalt/silicon carbide high-velocity oxygen fuel coatings

This study offers an in-depth analysis of the electrochemical corrosion behaviour of tungsten carbide-cobalt/silicon carbide coatings on AISI 304 stainless steel, applied using high-velocity oxygen fuel spraying. The coatings were produced with varying silicon carbide concentrations (25%, 40%, 60% and 75%) to evaluate their effectiveness in enhancing corrosion resistance. Microstructural analyses were conducted using SEM and EDS, while corrosion behaviour was assessed through open-circuit potential and Tafel tests in a NaCl solution. The findings indicate that increasing the silicon carbide content increases surface roughness and coating thickness. Additionally, the corrosion results revealed that coatings with higher silicon carbide concentrations exhibited more negative potential values, indicating improved corrosion resistance due to passivation effects.

Sustainable innovations: Mechanical and thermal stability in palm fiber-reinforced boron carbide epoxy composites

This study reports the development of a sustainable composite material by integrating boron carbide (B4C) nanoparticles into palm fruit fiber (PFF)-reinforced epoxy matrices. The mechanical and thermal properties of these composites were thoroughly assessed, yielding promising results across key performance metrics. Tensile strength increased to 41.73 MPa with 4 % B4C, while flexural strength reached 43.29 MPa at the same concentration. Impact energy also saw an improvement, peaking at 5.6 kJ/m² with 4 % B4C. Similarly, hardness values showed an upward trend, with a Shore D value of 73. Additionally, water absorption was reduced from 7.2 % to 5.3 %, indicating enhanced moisture resistance. Thermal analysis confirmed the superior thermal stability of the composite, as shown by Thermogravimetric Analysis (TGA) and Differential Thermogravimetry (DTG) curves, with the maximum mass loss occurring at a higher temperature for the 4 % B4C composite. Fatigue stress testing also demonstrated improved durability, with the 4 % and 5 % composites exhibiting higher fatigue resistance over multiple cycles. The findings suggest that a 4 % concentration of boron carbide achieves an optimal balance of improved mechanical strength, durability, and thermal stability, making these composites suitable for high-performance applications while promoting environmental sustainability.

Binder Jetting Additive Manufacturing of Inconel 718/TiC Metal Matrix Composites: Influence of TiC Content on Processing, Microstructure, Mechanical and Tribological Properties.

This paper investigated the influence of titanium carbide (TiC) content on the processing, microstructure, mechanical and tribological properties of Inconel 718/TiC composites produced by binder jetting additive manufacturing. It was found that increasing the amount of TiC required an increase of the drying intensity during printing due to a decrease in the thermal conductivity of the powder mixture. The sintering process also depended on the TiC content. The most optimal modes were 1270 °C for 10 h for samples with 0 and 3% TiC and 1280 °C for 5 h for samples with 5 and 10% TiC. The hardness of the materials increased as the proportion of reinforcement increased. The best tensile properties, also at high temperatures, were possessed by samples with 3% TiC, showing high strength and, in addition, satisfactory plasticity. The maximum wear resistance was achieved by the composite material containing 5% TiC.

Effect of Carbide Precipitation on Hardness and Wear Resistance of H13 Steel

The carbide precipitation of H13 steel and its effect on hardness and friction and wear resistance are investigated by microstructure observation, phase analysis, and mechanical property test. Results show that the tempering hardness is mainly related to the content of secondary carbides. After solution treatment in the temperature range of 1040–1070 °C, quenching and tempering, with the increase of the solution temperature, the content of secondary carbides and hardness of H13 steel in the tempering microstructure increase first and then decrease, and both reach the maximum value when the solution temperature is 1060 °C. The change of hardness is consistent with that of the content of secondary carbides. When the solution temperature is 1040 °C, the wear mass loss of the tempered H13 steel is the least, which is 4.63 mg, indicating that its wear resistance is the best, and this is caused by the presence of more undissolved carbides in the tempering microstructure. With the increase of the solution temperature, the wear mass loss increases gradually, and the wear resistance decreases, which is mainly related to the content decrease of undissolved and secondary carbides and the content increase of residual austenite.

Effect of TaC content on microstructure and wear behavior of PRMMC Fe-TaC coating manufactured by electrospark deposition on AISI304 stainless steel

The Fe-TaC coatings on stainless steel by electrospark granule deposition in an anode mixture of iron granules and tantalum carbide powder were first obtained. The material deposition rate on the substrate increased with the TaC powder concentration growth in the anode mixture, facilitating the initiation of electrical discharges. X-ray analysis of deposited coatings shows the presence of the TaC, γFe, and αFe phases. The tantalum carbide concentration grows with an increase in the content of TaC powder in the anode mixture, from 2.4 to 14.8 vol%. The dependence of the wear rate of coatings on the concentration of tantalum carbide in the anode mixture had a parabola form, with a minimum of 5 vol%. However, with a further increase in the TaC concentration in the anode mixture, the wear rate of the coatings monotonically increased due to spalling of TaC grains due to a deficiency of the metal binder.

Normalizing temperature influence on the microstructure characteristics, mechanical and wear performance of a novel high chromium cast iron

The microstructure, mechanical and wear behavior of a high chromium cast iron were studied at different normalizing temperatures (950°C, 1000°C, 1050°C, 1100°C). The martensite content was proportional to the normalizing temperature except at 1100°C because of the appearance of retained austenite. As the temperature increased, the primary carbide downsized whereas the secondary carbide content first increased but then decreased, contributing to the superior mechanical properties observed tempered at 1050°C. The superior hardness and strength improved the surface deformation resistance, including enhanced work-hardening in the matrix and stacking fault locks in carbides, hindering dislocation slipping and material spalling, thus achieving excellent wear properties when normalized at 1050°C. Moreover, the wear mechanism changed from oxidative/fatigue to abrasive/adhesive wear as the temperature increased.

The regulation of dislocation and precipitated phase improving hydrogen embrittlement resistance of pipeline steel in high pressure hydrogen environment

In this study, the hydrogen embrittlement behavior of quenched pipeline steel tempered at 550 °C to 650 °C in a high-pressure hydrogen environment was analyzed. Hydrogen permeation tests and microstructural analyses indicated that the dislocation density of the steel decreases with increasing tempering temperature, while precipitates gradually nucleate and grow. These hydrogen traps interact with hydrogen atoms, resulting in significantly higher diffusible hydrogen content in steel tempered at 550 °C compared to that tempered at 600 °C and 650 °C. Fatigue crack growth (FCG) test results show that steel tempered at 600 °C and 650 °C exhibits significantly better hydrogen embrittlement resistance than steel tempered at 550 °C. This is primarily due to the combined effect of the high hydrogen concentration, high dislocation density and low nano carbide content in the steel tempered at 550 °C, which inhibits dislocation slip and emission, leading to high crack tip stress and rapid crack propagation. In contrast, the low dislocation density and and dispersed nano carbides in steel tempered at 600 °C and 650 °C facilitate some dislocation slip and emission, result in crack tip stress relaxation and reduced crack propagation rate. Properly controlling the initial dislocation density and increasing the density of irreversible hydrogen traps can enhance the strength of materials while improving their resistance to hydrogen embrittlement.

Field-assisted sintering of MC-Ti3SiC2 composites with adjustable thermal expansion coefficient

Tool materials for precision glass moulding made of WC or SiC bear the risk of glass breakage due to a difference in the coefficient of thermal expansion (CTE) between the mould and the glass. The aim of this study is to develop a MAX phase composite with increased CTE and thus reduced CTE difference. A mixture of Ti3SiC2 and 10 vol% SiC powder was sintered between 1250 °C and 1350 °C using the field-assisted sintering technique (FAST). In addition to the sintering temperature, the dwell time and the initial particle size were varied using a full factorial experimental design. Complete densification, homogeneous carbide distribution and no grain coarsening were observed for specimens sintered at 1300 °C for 10 min at 50 MPa. The grain size of SiC and Ti3SiC2 is approximately 0.3 μm, although larger grains occasionally occur. Identified process parameters were successfully transferred to TiC reinforced Ti3SiC2 composites. While the carbide content can be specifically controlled by mixing, the MAX phase partially decomposes during sintering. MC additions between 10 and 30 vol% resulted in an adjustable CTE in the range 6.8–9.0 ppm/K.

Simulation methods for local microstructure evolution-cooling and time–temperature transformation behavior in heat treatment of tool steels

This paper presents the development of a simulative workflow capable of predicting microstructural evolution during heat treatment processes. It represents a meaningful advance in this field by extending existing simulation models previously published by the authors. In this previous work, the software solutions MatCalc®, MATLAB®, and Abaqus FEA® were coupled to calculate several local microstructural properties: the carbide content, the type, the distribution, and the chemical composition of the matrix. In addition, the model could determine the proportions of microstructural components such as martensite and retained austenite within the matrix. The hardening treatment was simplified by assuming a fast quenching, leading to complete martensitic phase transformation. However, this assumption may not be valid for larger components, leaving room for optimization. Therefore, the simulation model in this publication has been successfully extended to include local solution-state dependent time–temperature transformation behavior. In addition, an automated microstructure simulation of the entire component is now possible. As an application example, two tool geometries of different sizes were simulated with an identical furnace heat treatment. The same furnace temperature (T = 1050 °C) and the same holding time (t = 60 min) were simulated with a slow air cooling (Tair = 25 °C). The austenitizing temperature and holding time were chosen to dissolve a sufficient amount of carbides during austenitization, and the slow cooling rates were chosen to form diffusion controlled phases such as bainite or pearlite. To validate the simulation model, the simulated time–temperature sequences were reproduced experimentally in a quenching dilatometer. The resulting real microstructures were compared with the simulated ones.

Adapting high-speed indentation mapping for investigating microstructure-property correlations in chromium carbide-nickel alloy coatings: Challenges and solutions

This study investigates the microstructural and mechanical characteristics of chromium carbide‑nickel rich alloy coatings produced through laser cladding, detonation spraying, and plasma spraying techniques. While all three processing techniques used the same feedstock powder, each method yields coatings with unique microstructures encompassing varying compositions and length scales. Employing Field Emission Scanning Electron Microscopy (FE-SEM) in combination with Energy Dispersive Spectroscopy (EDS) and nanoindentation mapping, local microstructure and mechanical properties were assessed at the micrometre length scale. Laser-clad coatings exhibit a typical metal matrix composite microstructure with high carbide content, distinct (MoNb)C2 phases, and Fe in the metallic matrix, while the thermal sprayed coatings showed carbides of varying sizes and metallic matrix with varying degrees of chromium dissolved in it. The instrumented indentation technique helped precisely record the microstructural features in all the coatings. Chromium carbide consistently emerges as the hardest phase across all coatings, with variations in metallic matrix hardness. Higher matrix hardness in thermal sprayed coatings correlates with increased Cr content, attributed to extended solid solubility of Cr and the presence of Mo and Nb. Energy dispersive spectroscopy and transmission electron microscopy provided clearer insight into the microstructure. This study highlights a direct one-to-one correlation between microstructure and mechanical properties mapped using instrumented indentation techniques in chromium carbide‑nickel rich coatings across different deposition methods.

Experimental, simulation, and theoretical investigations of gamma and neutron shielding characteristics for reinforced with boron carbide and titanium oxide composites

This study investigates the radiation shielding properties of composites containing polyester resin, boron carbide and titanium oxide in varying proportions. The radiation transmittance of the produced composites was measured using radioactive sources 241Am, 137Cs, 133Ba, 60Co, and 22Na across a photon energy range of 59.5 keV–1332.5 keV. To analyze radiation permeability, experimental geometry was simulated using Monte Carlo-based computer codes Monte Carlo N-Particle (MCNP), Particle and Heavy Ion Transport code System (PHITS) and FLUktuierende KAskade or Fluctuating Cascade (FLUKA), and the experimental data were compared with simulation results and theoretical data obtained from WINXCOM. The findings demonstrated a high degree of consistency between experimental, simulation, and theoretical results. Notably, the BCTiO50 sample, which included a 50% addition of TiO2, emerged as the most effective in photon radiation shielding. In addition to gamma shielding, the neutron shielding properties of the produced composites were evaluated using the FLUKA code, revealing that the BCTiO0 sample, with the highest percentage of boron, provided the best neutron shielding. This analysis included composites with decreasing boron carbide content by 10%, 20%, 30%, 40%, and 50% by weight, each replaced with titanium oxide, showcasing the potential applications of these polymer composites in radiation shielding.

Carburization Behavior of High-Grade Pellets After Direct Reduction in Pure Hydrogen

AbstractCarburization is a critical aspect in the iron and steel industry as it significantly affects the mechanical and chemical properties of the final product. This study provides a comprehensive analysis of the carburization potential of high-grade quality iron ore pellets after direct reduction in pure hydrogen. The results show that the porosity of the pellets has a significant impact on the efficiency and success of the direct reduction process with hydrogen. The reduction process can be completed at a lower temperature in pure hydrogen compared to carbon monoxide, with the iron carbide concentration peaking at temperatures up to 500 °C before decreasing with further temperature increases. The uniform distribution of SiO2, Al2O3, and CaO is critical to the carburizing process and affects the final properties of the steel. An increased degree of metallization and porosity are associated with an improved carburizing tendency. This study highlights the intricate interplay between temperature, carbon sources, and the resulting equilibrium concentration of iron carbides and provides insights into the complex dynamics of this phenomenon. Graphical Abstract

Hydrogen technologies for decarbonization of ferrous metallurgy: scientific background and technical capabilities

To date, the use of ferrous hydrogen in metallurgy is considered from several positions. First, the partial or complete replacement of carbon with hydrogen reduces greenhouse gas emissions of CO2. Secondly, due to the different chemical affinity for oxygen, it becomes possible to selectively (selectively) extract components from complex complex ores and man-made materials. Thirdly, the absence of carbon in the reaction zone will make it possible to obtain a metal with a low content of carbides, which in many cases increases the demand for the product. Thermodynamic calculations of a multicomponent oxide system (Ni, Fe, P, Zn, Mn, V, Cr, O) in the presence of various reducing agents: carbon, hydrogen are performed using the TERRA software package, and their combined effects are considered. It is shown that the type of reducing agent affects the temperature of the beginning of the reduction of metals and the degree of their metallization. Thus, by selecting the type of reducing agent, its quantity, and the temperature of the process, it is possible to selectively extract some metals, and leave others in an oxidized state. Ilmenite concentrate in the form of a briquette was used in laboratory tests. The analysis of the iron reduction process using carbon or hydrogen as a reducing agent has been carried out. In comparison with the results obtained using carbon, the kinetics of iron reduction with hydrogen is higher. At the same time, the reduction proceeds with the formation of metallic iron, rutile (TiO2) and residual ilmenite. Whereas, in a carbothermic process occurring at higher temperatures (1000–1300 ℃), the reduction products are iron and iron ditanate (FeTi2O5). In addition, an important advantage of selective reduction by gas is the possibility of subsequent separation of the metallic and oxide phases by melting, without fear of secondary reduction due to solid carbon residues.

First-Principles study of hydrogen solubility and embrittlement of Cr23C6 in nickel-based alloys

This research examines the crucial role played by Cr23C6 carbides in hydrogen trapping and their subsequent impact on the mechanical properties of the material. The hydrogen solution energies at different defect sites within the bulk phase of Cr23C6 and the Ni/Cr23C6 interface were analyzed using first-principles computations. This study underscores the notable vulnerability of nickel-based alloys to hydrogen embrittlement as the carbide content increases. Substantial hydrogen enrichment at the Ni/Cr23C6 interface, particularly at octahedral interstitial sites on the Ni side and C vacancies at the interface, was identified through comprehensive atomistic simulations. This enrichment negatively affects separation at the interface, indicating an increased risk of brittle fracture in the presence of hydrogen. By providing insights into the microscopic processes involved, our results seek to contribute to the development of nickel-based alloys that are more resistant to hydrogen, thereby influencing material selection and treatment in industrial applications prone to hydrogen embrittlement.

Effect of silicon carbide content on microstructure, physical and mechanical properties in vat photopolymerization of alumina

AbstractVat photopolymerization (VPP) printing of ceramic parts offers advantages such as low cost, simple operation, and short fabrication cycles. However, drawbacks include low toughness and brittleness in the printed parts. This study explores enhancing the toughness and strength of alumina (Al2O3) ceramics by incorporating silicon carbide (SiC) particles as additives. The impact of varying SiC contents on the quality of VPP‐printed Al2O3 parts is examined, encompassing microstructure, physical properties, and mechanical properties. Results indicate that optimal SiC addition reduces Al2O3 ceramics' porosity, enhances crystalline quality, and boosts mechanical properties. Excessive SiC, however, diminishes these benefits. The most significant strengthening of Al2O3 parts occurred with a 1.5 wt.% SiC content, increasing bending strength and fracture toughness by 239.7% and 564.7%, respectively. This underscore SiC's positive role in enhancing the quality of VPP‐printed Al2O3 parts.

Combination effects of laser heating and water cooling on the repair performance of Hastelloy C-276 by underwater laser direct metal deposition

The Ni-based Hastelloy C-276 was repaired by in-air and underwater laser direct metal deposition (in-air DMD and UDMD) with four gradient cooling rates (in-air DMD, in-air DMD with interlayer cooling, UDMD and UDMD with each layer re-covered by water). The microstructure and mechanical properties of repaired samples were systematically characterized with respect to the cooling rates. All samples presented good metallurgical bonding and columnar dendrites with epitaxial growth. The underwater environment had a more pronounced acceleration effect on the cooling rate compared to interlayer cooling. The rapid cooling induced intense thermal cycling, resulting in increased dislocation density and grain refinement with primary dendrite arm spacing (PDAS) diminishing from 5.30 to 3.21 μm. Accelerated cooling rate contributed to precipitation of massive M6C carbides. Carbides coarsened (sizes from 257 to 354 nm) and exhibited a reduced content as cooling rate slowed down due to intrinsic heat treatment (IHT). The residual water film in UDMD repair promoted oxide formation. Samples with increased cooling rates exhibited superior mechanical performance. The improved microhardness, tensile and impact properties were primarily attributed to the enhanced fine grain strengthening and Orowan strengthening facilitated via reduced grain size, increased dislocation density and carbide content. Quantities of large-size carbides were detrimental to tensile and impact properties as displayed in the in-air DMD sample with interlayer cooling (carbide size of 341 μm). The study could serve as a reference for in-situ restoration in deep-water environments.

Effect of Cr3C2 content on the tribo-corrosion behaviors of Cr3C2-NiCr/DLC duplex coatings

Duplex coatings consisted of a Cr3C2-NiCr intermediate layer with varying carbide content and a top DLC film were fabricated by combining high-velocity oxygen-fuel (HVOF) and physical vapor deposition (PVD) methods. The study focused on effect of Cr3C2 content in the intermediate layer on the tribo-corrosion behaviors of the Cr3C2-NiCr/DLC duplex coatings. The result showed that as the Cr3C2 content increased, the porosity of the duplex coating increased gradually, leading to a decrease in corrosion resistance. The tribo-corrosion behaviors of the duplex coatings were ultimately governed by the synergistic effect of their tribological and electrochemical performances. Notably, the Cr3C2 (35 wt%)-NiCr/DLC duplex coatings exhibited a relatively positive corrosion potential, a low corrosion current density, and the lowest wear rate, indicating superior tribo-corrosion resistance. Further increasing the Cr3C2 content led to a continuous increase in the promotion effect of corrosion on wear, especially when the Cr3C2 content was 80 wt%, the material volume loss caused by this effect accounted for 61.37 % of the total. The predominant wear mechanism of the duplex coatings changed from abrasive wear to corrosion wear with the increase of Cr3C2 content.

Hot oscillating pressing sintered AlCoCrFeNi/nanodiamond high-entropy alloy composites

AlCoCrFeNi/nanodiamond high-entropy alloy composites were successfully prepared by hot oscillating pressing (HOP) at different sintering temperatures in this work. The microstructures of the HOPed composites consisted of the FCC phase, BCC phase and nanocarbide phase uniformly distributed in the particles interstices. With the temperature increasing, the original powder particle boundaries gradually disappeared, the density progressively increased, and the microstructure defects decreased. At 1100 °C, its maximum density reached to 99.7 %. Moreover, the FCC phase volume fraction and carbide content further increased without significant microstructure coarsening. The hardness and corrosion resistance of the HOPed samples were better than the hot pressing (HP) samples because the original particle boundaries and pores became smaller, and a small number of nanocarbides were uniformly distributed. Then its maximum hardness reached to 566.48 HV1, and the minimum corrosion current density and corrosion rate was 2.916 μm/cm2 and 0.013 mm/year, respectively, which was better than other alloys reported.

Температуры окисления инструментальных вольфрамокобальтовых твердых сплавов

Introduction. Products containing WC-Co cemented tungsten carbides are commonly used in various industries. It is often operates at elevated temperatures, at which, as noted in the literature, tungsten carbides are susceptible to severe oxidation in air. However, no sufficiently accurate values of oxidation temperatures and dependence of these temperatures and the oxidation rate of tungsten carbides on the cobalt content with its wide variation have been established. The subject of the study is the oxidation process of WC-Co cemented tungsten carbides. The purpose of the work is to obtain the oxidation temperatures of WC-Co cemented tungsten carbides with different cobalt content by weight in the range of 3–20 %. Methods. The dynamics of oxidation was studied in air. Specimens of the same length were heated to a temperature of 850 °C and cooled at the same rate in the furnace of a push-rod dilatometer Netzsch 402 PC while its expansion was simultaneously recorded. The oxidation rate of the specimens was determined by the difference in its length before heating and after cooling. The values of oxidation temperatures were obtained by mathematical analysis of relationships of the expansion on temperature. Results and discussion. Experimental dependences of expansion of WC-Co cemented tungsten carbides on temperature in the range from 20 to 850 °C, and for WC-8Co – up to 1,150 °C, were obtained. The oxidation rate of WC-Co cemented tungsten carbides increased linearly with increasing concentration of tungsten carbides (decreased with increasing cobalt content). During heating, two characteristic temperatures were identified: the onset of oxidation (631±4 °C) and the transition to active oxidation (804±11 °C). The established temperatures were the same for different ratios of tungsten carbides and cobalt. The results can be used when choosing temperature conditions for products made from WC-Co cemented tungsten carbides.

Optimizing wear resistance of ZA-27 alloy through analytical modelling: A study on the effect of titanium carbide content, load, and speed

Optimizing wear resistance of ZA-27 alloy through analytical modelling: A study on the effect of titanium carbide content, load, and speed