Search Results (133)

Boron carbide (B₄C) holds significant application potential in the fields of lightweight, high-hardness protective and high-end wear-resistant components due to its low density and exceptional hardness. However, its strong covalent bonding leads to low sintering activity and weak grain-boundary cohesion, resulting in high brittleness and crack sensitivity. These inherent properties make it difficult to achieve simultaneous full densification and toughness enhancement, severely limiting the reliability of B₄C under complex service conditions. Although diamond is an attractive reinforcement because of its high elastic modulus and low coefficient of thermal expansion, the simultaneous realization of densification, graphitization suppression, and fracture-resistance improvement in diamond/B₄C composites remains insufficiently understood. In this study, diamond particles were introduced into the B₄C matrix and consolidated by rapid high-temperature and high-pressure (HTHP) sintering to synergistically promote densification and fracture toughening. The effects of sintering temperature and diamond content on phase evolution, densification, microstructure, and mechanical properties were systematically investigated, and the associated toughening mechanisms were analyzed. The results indicate that the hardness generally increases with rising sintering temperature and diamond content. The primary toughening mechanisms are identified as the pull-out of diamond particles and crack deflection induced by residual stresses generated during the cooling process. Although the composite with 20 wt.% diamond exhibits higher hardness, it also experiences severe macroscopic cracking. The composite with 10 wt.% diamond sintered at 1450 °C under 5.3 GPa for 4 min exhibits the optimal balance of properties, achieving a relative density of 98.85%, a Vickers hardness of 40.72 GPa, and a fracture toughness of 9.20 MPa·m^1/2. This work confirms the effectiveness of combining diamond reinforcement with HTHP sintering in simultaneously achieving densification and toughening of B₄C-based composites, providing a new pathway for developing high-performance lightweight protective ceramics. Full article

Copper and its alloys are widely used in electrical, automotive, aerospace, and energy applications because of their excellent thermal and electrical conductivity. However, the low hardness and poor wear resistance of pure Cu limit its use under tribologically demanding sliding conditions. In this study, Cu matrix composites reinforced with 1 wt.% boron carbide (B₄C), boron (B), chromium (Cr), cobalt (Co), alumina (Al₂O₃), and graphite (Gr) were fabricated by powder metallurgy and comparatively evaluated under identical processing and testing conditions. Phase constitution and microstructural characteristics were analyzed by XRD, SEM, and EDS, while mechanical and tribological behavior was assessed by Vickers hardness and dry sliding wear tests. All reinforcements improved the hardness of the Cu matrix compared with unreinforced Cu. The hardness increase followed the order Cu–B₄C (68.91%) > Cu–B (66.43%) > Cu–Gr (63.97%) > Cu–Al₂O₃ (61.79%) > Cu–Cr (42.69%) > Cu–Co (36.04%). Dry sliding wear tests, performed under a 10 N normal load, 0.05 m s⁻¹ sliding speed, and 1000 m sliding distance against a 316L stainless-steel ball, showed that all reinforced composites exhibited lower mass loss and more stable sliding behavior than pure Cu. Among all samples, Cu–B₄C displayed the best wear performance, with a 154.8% improvement in wear resistance relative to pure Cu. SEM analysis of the worn surfaces revealed that reinforcement addition reduced severe plastic deformation, groove formation, and delamination, leading to a more stable wear regime. Graphite- and boron-containing composites benefited from interfacial lubrication and contact stabilization, whereas B₄C and Al₂O₃ improved wear resistance through rigid-particle strengthening and enhanced load-bearing capacity. By comparing ceramic, metalloid, metallic, oxide, and solid-lubricating reinforcements at the same low addition level and under identical processing and testing conditions, this study provides a reinforcement-selection framework for Cu-based composites requiring improved hardness and dry-sliding durability. Full article

Hard ceramic coatings are essential for extending the performance of metal parts under the extreme heat and stress found in aerospace and defense environments. There is a major knowledge gap regarding this topic in the current literature. While there has been significant research on individual fabrication methods or specific coating materials separately, no previous review has combined experimental lifecycle data with a broad computational design approach that covers the entire design-to-deployment process. This review fills that gap by offering a unified roadmap from integrated computational materials engineering (ICME) to machine learning (ML). This roadmap speeds up the rational design of coatings for next-generation aerospace systems. The practical importance of this framework is its clear use in gas turbine engine qualification, hypersonic vehicle thermal protection, and landing gear surface engineering. It can cut down on experimental trial-and-error cycles by allowing ML-guided composition screening and condition-based maintenance through digital twin integration. The main ceramic material systems, tungsten carbide (WC), boron nitride (BN), boron carbide (B₄C), silicon carbide (SiC), alumina (Al₂O₃), and zirconia (ZrO₂), are examined for their protective roles in aerospace-grade alloys. A key contribution is the multiscale computational framework that includes density functional theory, molecular dynamics, finite element analysis, and ML-driven inverse design. Together, these methods improve predictions for thermal breakdown, multi-axial stress responses, and coating lifetime. Future research should focus on ultra-high-temperature ceramics, multifunctional self-healing coatings, and surface engineering methods driven by data. Full article

In this research, the effects of density and porosity on the mechanical properties of a stir-cast hybrid magnesium ZE41 alloy strengthened with 2% weight of silicon carbide (SiC) and boron carbide (B₄C) are assimilated. The experimental and theoretical densities of the ZE41 hybrid matrix were found and compared. From the results of density analysis, it can be inferred that the experimental density of hybrid matrix is smaller when compared to the pure ZE41 matrix. The percentage porosity of hybrid matrix was also analyzed, and it was observed that the hybrid matrix has a slight increase in porosity when compared to the pure ZE41 matrix. The ultimate strength and hardness of the ZE41 hybrid matrix have increased significantly due to its moderate density and acceptable porosity values. Full article

Boron carbide (B₄C)-reinforced metal matrix composites (MMCs) are promising candidates for biomedical implants due to their mechanical properties and potential biological compatibility. In this study, in vitro biocompatibility and cytotoxicity of B₄C-reinforced CoCrMo, Ti, and 17-4 PH alloys were systematically evaluated using human osteoblast (HOB) cells. Composites were fabricated via powder metallurgy with varying B₄C reinforcement ratios (CoCrMo and Ti: 5–10 wt%; 17-4 PH: 3–12 wt%). Extracts prepared according to ISO 10993-12 standards were applied at different concentrations (100%, 50%, 25%, 12.5%) to assess cell viability using the MTT assay over 24, 48, and 72 h. Results demonstrated a clear dose-dependent cytotoxic effect across all composite systems. Ti composites exhibited the highest biocompatibility, with cell viability largely preserved even at higher B₄C ratios. CoCrMo composites showed moderate cytotoxicity, which decreased upon extract dilution, indicating low-concentration compatibility. In contrast, 17-4 PH composites revealed significant cytotoxicity at higher extract concentrations, exacerbated by increasing B₄C content. Literature-supported findings confirm that B₄C incorporation enhances hardness, wear resistance, and elastic modulus, yet excessive reinforcement can induce local stress and particle detachment, affecting cellular tolerance. Diluted extracts of Ti and CoCrMo composites maintained cell viability at a biocompatible level consistent with ISO 10993-5 criteria. These results highlight the promising biocompatibility of B₄C-reinforced Ti and CoCrMo alloys for biomedical applications and provide a biological basis for the design of next-generation composite implants. Full article

In this study, the effect of boron carbide (B₄C), hexagonal boron nitride (hBN), holy super graphene (HSG), and hybrid (B₄C + hBN + HSG) nano-additives on the tribological performance of SAE 5W-30 gasoline engine oil was investigated on Al-Si-based samples (Al 4032) prepared by cutting from a single-cylinder gasoline engine block. The addition of nano-additives regularly increased the kinematic viscosity; the 63.80 mm²/s (BO) value rose to 68.90 mm²/s at the highest level of B₄C and to 70.50 mm²/s in the hybrid oil (≈10.5% increase). The lowest and most stable friction performance was found in the hybrid 0.025 g/25 mL nano-additive oil, which remained between 0.03 and 0.05 during the entire COF test. The EDS mapping and line scan results confirmed the formation of tribofilm by identifying the additive elements (B for B₄C, B and N for hBN, C for HSG) in the wear scar, and the presence of increased O elements showed the restricted formation of tribo-oxidation. The results show that hybrid nano-additive oils provide the most effective friction and wear improvement, especially at low concentrations, while at high additive levels, performance does not show a consistent increase due to particle accumulation and third-body effects. Full article

In this study, boron carbide (B₄C), hexagonal boron nitride (hBN), holy super graphene (HSG), and hybrid (B₄C+hBN+HSG) nano-additives were added to SAE 15W-40 diesel engine oil at a range of 0.03–0.24 g per 30 mL of oil, and reciprocating tribological tests were conducted on a GG25 (EN-GJL-250) gray cast iron-based diesel piston surface in contact with an Al₂O₃ ball (Ø6 mm) at a load of 20 N, a sliding distance of 500 m, and a temperature of 75 °C. XRD analysis showed that the dominant phase on the piston surface was the α-Fe matrix and that no significant new phase had formed. The results obtained revealed that the nano-additive effect is strongly dependent on both the additive type and the additive level. At a low level (0.03 g/30 mL) of B₄C additive, the average COF decreased by approximately 19%, while at a low level (0.03 g/30 mL) of hBN additive, this decrease amounted to approximately 54%. In the HSG additive, at the highest level (0.24 g/30 mL), the coefficient of friction (COF) decreased to ≈0.032, achieving a friction reduction of approximately 75% compared to the base oil. In the hybrid oil series, COF values remained in the range of approximately 0.082–0.087 at all additive levels and were generally 25–28% lower than those of the base oil. SEM/EDS examinations showed that a tribofilm with high carbon content formed in the HSG-additive oils, while a tribofilm layer containing C, B, and N elements together formed in the hybrid-additive oils. Overall, it was concluded that selecting the appropriate additive type and level can reduce friction and wear losses at the piston interface, thereby contributing to engine efficiency by extending the life of engine components and limiting friction-induced energy losses. Full article

Silicon carbide (SiC) substrates have been widely adopted in high-performance applications such as power electronics, optoelectronics, and semiconductors. However, achieving high-quality processing remains a formidable challenge due to SiC’s inherent hardness and brittleness. This study investigates the effects of diamond and boron carbide (B₄C) abrasives on material removal rate (MRR) and surface roughness during the lapping of SiC substrates. The results demonstrate that the mix ratio of diamond to B₄C significantly affects the roughness of the lapped substrates. Increasing B₄C proportions results in lower Sa values. Nonetheless, excessive B₄C powder leads to insufficient abrasive lapping force. Furthermore, finer B₄C powder contributes to higher surface roughness and higher SiC removal rate. Additionally, the influence of different diamond powder sizes on the depth of subsurface damage (SSD) of lapped SiC substrates was evaluated using an atmospheric inductively coupled plasma (ICP) etching method. As the diamond particle size increased from 3 μm to 4 μm, the SSD depth rose from 1.56 μm to 2.16 μm. Furthermore, this study elucidates the lapping removal process of silicon carbide substrate from the mechanism, which can provide actionable guidance for refining lapping techniques in 4H-SiC substrate manufacturing. Full article

This study investigated the fabrication and characterization of polylactic acid (PLA)-based ceramic composite filaments for fused deposition modeling (FDM) 3D printing. Boron carbide (B₄C) and silicon carbide (SiC) were incorporated into PLA at various weight fractions (1–40 wt. % for B₄C and 1–20 wt. % for SiC) to produce composite filaments using a commercial extruder. The rheological properties, thermal stability, and printability of the filaments were evaluated. Filaments with low ceramic content exhibited satisfactory quality, whereas those with higher loadings required reprocessing to improve their dimensional stability and surface morphology. Successful printing was achieved with SiC contents of up to 8 wt. % using single-extruded filaments and up to 20 wt. % using double-extruded filaments. Rheological tests revealed that filaments with low ceramic content exhibited shear-thinning behavior, whereas those with higher loadings displayed nearly Newtonian-like behavior. Thermal analysis using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) determined the optimal processing temperature range for the composite filaments to be between 200 °C and 270 °C. High-temperature microscopy was used to study the temperature behavior of the B₄C-containing filaments and set the optimum printing temperature. The results demonstrate the feasibility of producing PLA-based ceramic composite filaments for FDM 3D printing with the potential to tailor the thermal and functional properties of the printed parts for specific applications. Full article

Copper (Cu) is widely used in electrical, electronic, and tribological systems owing to its excellent electrical and thermal conductivity. However, its relatively low hardness and poor wear resistance limit its use in demanding engineering applications. In this study, Cu-based hybrid metal matrix composites (MMCs) reinforced with hexagonal boron nitride (h-BN) and boron carbide (B₄C) were fabricated via spark plasma sintering (SPS) to improve their mechanical and tribological performance. The h-BN content was fixed at 1 wt.% to ensure solid lubrication, while the B₄C content was varied (0.25, 0.5, 0.75, and 1 wt.%) to examine its influence on the microstructural, mechanical, electrical, and wear properties of the composites. Microstructural analyses confirmed a homogeneous distribution of h-BN and B₄C particles in the Cu matrix at low and moderate reinforcement levels, whereas excessive B₄C resulted in partial agglomeration and reduced densification. All composites achieved relative densities above 95%, demonstrating the high densification efficiency of the SPS process. Hardness increased markedly with B₄C addition due to dispersion strengthening and grain refinement, while electrical conductivity decreased slightly because of the insulating nature of the reinforcements. Tribological tests showed that the composite containing 0.75 wt.% B₄C exhibited the best performance, with the lowest wear rate and stable friction behavior. Overall, the results indicate that co-reinforcing Cu with h-BN and B₄C through SPS is a promising strategy for developing multifunctional materials suitable for electrical contact and sliding applications. Full article

This study explores the fabrication and characterization of hybrid aluminum matrix composites reinforced with boron carbide (B₄C) and microsilica, produced via ultrasonically assisted stir casting followed by T6 heat treatment. Pure aluminum was selected as the base matrix to evaluate the combined effects of B₄C and microsilica reinforcements. Microstructural analyses showed that ultrasonic treatment effectively dispersed nanoparticles, reduced agglomeration, and enhanced particle–matrix interfacial bonding. T6 heat treatment further refined the grain structure through Zener pinning and promoted the formation of reaction layers at particle interfaces. Mechanical testing revealed that Al/B₄C composites provided the highest strength and hardness, while Al/microsilica systems retained superior ductility. The hybrid Al/B₄C/microsilica composites demonstrated a balanced combination of yield strength (38.6 MPa), ultimate tensile strength (82.6 MPa), and elongation (35.2%), confirming a synergistic strengthening–toughening effect. These results highlight the potential of Al/B₄C/microsilica hybrid reinforcements to optimize the trade-off between strength and ductility in aluminum-based composites. Full article

In this research article, a silicon carbide (SiC) nanocluster has been designed and characterized as an anode electrode for lithium (Li), sodium (Na), potassium (K), beryllium (Be), magnesium (Mg), boron (B), aluminum (Al) and gallium (Ga)-ion batteries through the formation of SiLiC, SiNaC, SiKC, SiBeC, SiMgC, SiBC, SiAlC and SiGaC nanoclusters. A vast study on energy-saving by SiLiC, SiNaC, SiKC, SiBeC, SiMgC, SiBC, SiAlC and SiGaC complexes was probed using computational approaches accompanying density state analysis of charge density differences (CDDs), total density of states (TDOS) and molecular electrostatic potential (ESP) for hybrid clusters of SiLiC, SiNaC, SiKC, SiBeC, SiMgC, SiBC, SiAlC and SiGaC. The functionalization of Li, Na, K, Be, Mg, B, Al and Ga metal/metalloid elements can raise the negative charge distribution of carbon elements as electron acceptors in SiLiC, SiNaC, SiKC, SiBeC, SiMgC, SiBC, SiAlC and SiGaC nanoclusters. Higher Si/C content can increase battery capacity through SiLiC, SiNaC, SiKC, SiBeC, SiMgC, SiBC, SiAlC and SiGaC nanoclusters for energy storage processes and to improve the rate performance by enhancing electrical conductivity. Full article

Nanoparticles suspended in a liquid alter the properties of the base liquid, expanding its fields of application. Nanodispersions can have several applications in solar energy, including serving as liquid sunlight absorbers, acting as optical filters in optics, or functioning as heat transfer fluids in solar thermal applications. However, for a precise evaluation of their use in a specific field, their properties must be carefully assessed. In this work, we use two different methods for the determination of the optical scattering and absorption coefficients of a nanodispersion of boron carbide (B₄C), and we compare the obtained results. Monochromatic measurements are performed at 635, 685, 730, and 830 nm, utilizing a technique that relies on the theory of optical scattering in an infinite medium. They are compared with spectrally resolved measurements of ballistic and total transmittance in the wavelength range of 400–850 nm, obtained using a spectrophotometer with an integrating sphere. The two methods are consistent and give results in good agreement. We also found that the mean radius of nanoparticles is higher than expected, confirming the non-negligible scattering. Full article

In this study, aluminium matrix hybrid composites reinforced with boron carbide (B₄C) and silicon carbide (SiC) were fabricated using the direct hot-pressing technique under 35 MPa pressure at 600 °C for 5 min. Particle size distribution and scanning electron microscope analysis were conducted for the input powders. The microstructure, mechanical properties, and drillability of the fabricated composites were examined. As the SiC content increased, the density decreased, hardness improved, and transverse rupture strength declined. Drilling experiments were performed based on the Taguchi L₁₈ orthogonal array. The control factors included cutting speed (25 and 50 m/min), feed rate (0.08, 0.16, and 0.24 mm/rev), point angle (100°, 118°, and 136°), and SiC content (0%, 5%, and 10%). Quality characteristics such as thrust force, torque, surface quality indicators, diameter deviation, and circularity deviation were evaluated. The Taguchi method was applied for single-response optimization, while the Entropy-weighted, Taguchi-based CoCoSo method was used for multi-response optimization. Analysis of Variance was conducted to assess factor significance, and regression analysis was used to model relationships between inputs and responses, yielding high R² values. The optimal drilling performance was achieved at 50 m/min, 0.08 mm/rev, 136°, and 10% SiC, and the confirmation tests verified these results within the 95% confidence interval. Full article

This study investigates the effect of boron carbide (B₄C) ceramic reinforcement on the microstructural, mechanical, electrical, and electrochemical properties of CoCrMo, Ti, and 17-4 PH alloys produced via powder metallurgy for potential biomedical applications. A systematic experimental design was employed, incorporating varying B₄C contents into each matrix through mechanical alloying, cold pressing, and vacuum sintering. The microstructural integrity and dispersion of B₄C were examined using scanning electron microscopy. The performance of the materials was evaluated using several methods, including Vickers hardness, pin-on-disk wear testing, ultrasonic elastic modulus measurements, electrical conductivity, and electrochemical assessments (potentiodynamic polarization and EIS). This study’s findings demonstrated that B₄C significantly enhanced the hardness and wear resistance of all alloys, especially Ti- and CoCrMo-based systems. However, an inverse correlation was observed between B₄C content and corrosion resistance, especially in 17-4 PH matrices. Ti-5B₄C was identified as the most balanced composition, exhibiting high wear resistance, low corrosion rate and elastic modulus values approaching those of human bone. Weibull analysis validated the consistency and reliability of key performance metrics. The results show that adding B₄C can change the properties of biomedical alloys, offering engineering advantages for B₄C-reinforced biomedical implants. Ti-B₄C composites exhibit considerable potential for application in advanced implant technologies. Full article