Search Results (84)

In this paper, SiC and Si/SiC ceramics were fabricated using direct laser powder bed fusion with chemical vapor infiltration. Their microstructure, mechanical properties and the impacts of silicon addition were analyzed. The incorporation of silicon led to an increase in the relative density of the silicon carbide ceramics from 76.4% to 78.3% and the compression strength increased from 39 ± 13 MPa to 90 ± 8 MPa after laser powder bed fusion with chemical vapor infiltration. The melting and re-solidification of silicon allows the silicon to encapsulate the silicon carbide grains, changing the microstructure and the failure mechanism of the silicon carbide ceramics, resulting in a small amount of silicon residue. In the LPBF-CVI SiC ceramic specimen, the LPBF-formed SiC exhibits a microhardness of 24.2 ± 1.0 GPa. In LPBF-CVI Si/SiC, the spherical dual-phase structure displays a moderately increased hardness (25.9 ± 4.4 GPa), and the CVI-formed SiC exhibits a hardness of 55.3 ± 9.3 GPa. Full article

This work presents a comparative analysis of the results of silicon carbide synthesis through the carbonization of Si (001) and Si (111) substrates in the temperature range 1130–1140 °C. The synthesis involved chemical vapor deposition utilizing thermally stimulated methane reduction in a hydrogen gas stream. The experiments employed an Oxford Nanofab Plasmalab System 100 apparatus on substrates from which the native oxide was removed according to established protocols. To minimize random experimental variations (e.g., deviations from set parameters), short synthesis durations of 3 and 5 min were analyzed. The resultant thin films underwent evaluations through several techniques, including X-ray photoelectron spectroscopy, X-ray diffractometry, optical emission spectroscopy with glow discharge, and transmission electron microscopy. A comparison and analysis were conducted between the results from both substrate orientations. Full article

Carbon fiber-reinforced composites (CFRCs) have attracted considerable attention in recent years due to their excellent properties, enabling their use across various sectors. However, their application at high temperatures is limited by the fibers’ lack of oxidation resistance. This study demonstrates a significant advancement in enhancing the oxidation stability performance of carbon fiber-reinforced composites (CFRCs) by developing a silicon carbide (SiC) coating through the ceramization of carbon fibers using silicon (Si) powder. For the first time, this method was applied to recycled carbon fibers from CF thermoplastic composites. The key findings include the successful formation of a uniform SiC coating, with coating thickness increasing with process duration and decreasing at higher temperatures. The treated fibers exhibited substantially improved oxidation resistance, maintaining structural stability above 700 °C—markedly better than that of their uncoated counterparts. Thermogravimetric analysis confirmed that oxidation resistance varied depending on the CF/Si ratio, highlighting this parameter’s critical role. Overall, this study offers a viable pathway to enhance the thermal durability of recycled carbon fibers for high-temperature applications. Full article

Silicon carbide (SiC) materials have demonstrated promising application prospects in modern manufacturing due to their outstanding physical and chemical properties. With its process flexibility and formation feasibility, binder jetting 3D printing technology has become a crucial technical approach to meet the demand for mass production of complex, high-performance SiC components. Addressing the technical challenges of traditional manufacturing techniques in achieving high-quality, complex-shaped SiC components, this paper systematically reviews the application of binder jetting 3D printing technology in fabricating high-quality SiC-based ceramic components, with a particular focus on the regulation of key process parameters affecting SiC green body formation quality and the optimization of post-densification processes. Firstly, this paper elaborates on the powder pretreatment, green part formation process, and post-processing chain involved in this technology, establishes an evaluation index system for formation quality, and provides research directions for rapid prototyping of SiC powders. Secondly, it provides an in-depth analysis of the influence patterns of jetting parameters (e.g., jetting conditions, powder characteristics, binder properties) and various post-processing techniques on the quality of SiC-based components, along with optimization methods to enhance the dimensional accuracy and mechanical properties of 3D-printed SiC components. Furthermore, this paper systematically summarizes advanced characterization methods for evaluating formation quality and demonstrates the technology’s application potential across multiple industrial fields through representative engineering cases. Finally, it predicts the future development trends of this technology and discusses potential application expansion directions and key scientific issues in current research, aiming to provide theoretical references for promoting in-depth development of this technology. Full article

The integration of Silicon Carbide (SiC) nanoparticles into Laser Powder Bed Fusion (LB-PBF) Molybdenum (Mo) printing represents a significant advancement in refractory metal additive manufacturing. Our investigation examined how varying SiC nanoparticle sizes affect the microstructural and electrical properties of LB-PBF-printed molybdenum components while maintaining a 0.01 mass fraction of Mo. At an Linear Energy Densities (LED) of 1.8 J/mm, the addition of 80 nm SiC particles achieved a 46% reduction in porosity, while sheet resistance decreased by 6% at LED of 2.0 J/mm with 80 nm SiC particles. These performance improvements stem from several mechanisms: SiC particles serve as oxygen scavengers, facilitate secondary phase formation, and enhance laser absorption efficiency. Their dual role as sacrificial oxidizing agents and Mo disilicide phase promoters represents a novel approach to addressing microcracking and porosity in LB-PBF-printed Mo components. Through systematic investigation of particle size effects on both microscale and nanoscale properties, our findings suggest that optimized nanoparticle addition could become a universal strategy for enhancing LB-PBF processing of refractory metals, particularly in applications requiring enhanced mechanical and electrical performance. Full article

Additive manufacturing (AM) technologies allow for the creation of components with greater design flexibility. The complexity in geometry and composition can enhance functionality, while parts made from multiple materials have the capacity to deliver improved performance. Nonetheless, most multimaterial printing methods are still in their infancy and face numerous challenges. Numerous materials require individual post-treatment, and some may not be compatible with each other regarding shrinkage, melting or sintering temperatures, and interactions. In this study, we introduce a technique for producing a metal–ceramic multimaterial prototype for electronic packages through powder-bed additive manufacturing technology. Silicon carbide-based ceramic substrate was manufactured by selective laser melting, on which molybdenum-based conductive tracks were printed. The results indicated that the SiC-based samples exhibit a relatively uniform microstructure with homogeneously distributed porosity. Mo-based powder containing 5% silicon was successfully SLM-ed on the SiC layer. The microstructural and chemical analyses show that Mo reacted with Si during selective laser melting, resulting in formation of molybdenum silicides. The surface of Mo-based layer surface is smooth; however, there are few cracks on it. The Vickers hardness was measured to be 7.6 ± 1 GPa. The electrical resistivity of the conductive track is 2.8 × 10⁻⁵ Ω·m. Full article

The microwave heating of silicon carbide is induced at a specific frequency of 2.45 GHz, leading to rapid heating within a temperature range of several hundred degrees Celsius. In this study, a mechanochemical curing process using iodine was employed to cure polycarbosilane (PCS), followed by the addition of carbon nanotubes (CNTs) to produce mixed polymer powders. The effects of the CNT addition on the microstructure, crystalline structure, and microwave heating properties were investigated. The findings indicated that the incorporation of CNTs generally led to a reduction in the number of micropores; however, when the CNT concentration exceeded 10 wt%, the aggregation of CNTs became evident. In terms of microwave heating properties, the sample containing 0.1 wt% CNTs achieved the highest temperature, whereas samples with a higher CNT content demonstrated a heating limit of approximately 500 °C. Remarkably, post-processing of the specimens with 10 wt% CNTs enabled rapid heating to approximately 1800 °C within 4 s of microwave exposure. Full article

Magnetorheological–chemical-polishing tests are carried out on single-crystal silicon carbide (SiC) to study the influence of the process parameters on the polishing effect, predict the polishing results via a back propagation (BP) neural network, and construct a model of the processing parameters to predict the material removal rate (MRR) and surface quality. Magnetorheological–chemical polishing employs mechanical removal coupled with chemical action, and the synergistic effect of both actions can achieve an improved polishing effect. The results show that with increasing abrasive particle size, hydrogen peroxide concentration, workpiece rotational speed, and polishing disc rotational speed, the MRR first increases and then decreases. With an increasing abrasive concentration and carbonyl iron powder concentration, the MRR continues to increase. With an increasing machining gap, the MRR shows a continuous decrease, and the corresponding changes in surface roughness tend to decrease first and then increase. The prediction models of the MRR and surface quality are constructed via a BP neural network, and their average absolute percentage errors are less than 2%, which is important for the online monitoring of processing and process optimisation. Full article

Novel catalytic silicon carbide membrane filters (SCMFs) are synthesized with Co/Al–layered double hydroxide (Co/Al-LDH)-coated silicon carbide powder. After capsuled in a self-designed membrane shell, the SCMFs are utilized in activating persulphate for aniline degradation. Thermal analysis conducted via TG/DTG/DSC examination shows that the heating treatment is beneficial in elevating the activating ability of SCMFs, and the derived Co₃O₄ displays superior catalytical efficiency than Co/Al-LDHs precursor. The XRD patterns and SEM images indicate the sheet-like Co/Al-LDHs are uniformly coprecipitated throughout the surface of SCMFs. Within 20 min, around 95% of aniline is eliminated under 0.7 m of flow velocity and 8:1 of persulphate to aniline ratio. Three-dimensional fluorescence and GC chromatography reveal that distinct by-products exist in the early stage of the aniline degradation process between the sintered and non-sintered Co/Al-LDH-coated SCMFs. The integration strategy of Co/Al-LDH coatings and heating treatment endows traditional SCMFs with robust catalytic properties for engineering-oriented applications in wastewater treatment. Full article

Magnesium-based materials, which are known for their light weight and exceptional strength-to-weight ratio, hold immense promise in the biomedical, automotive, aerospace, and military sectors. However, their inherent limitations, including low wear resistance and poor mechanical properties, have driven the development of magnesium-based metal matrix composites (Mg-MMCs). The pivotal role of powder metallurgy (PM) in fabricating Mg-MMCs was explored, enhancing their mechanical and corrosion resistance characteristics. The mechanical characteristics depend upon the fabrication methodology, composition, processing technique, and reinforcement added to the magnesium. PM is identified as the most efficient due to its ability to produce near-net shape composites with high precision, cost-effectiveness, and minimal waste. Furthermore, PM enables precise control over critical processing parameters, such as compaction pressure, sintering temperature, and particle size, which directly influence the composite’s microstructure and properties. This study highlights various reinforcements, mainly carbon nanotubes (CNTs), graphene nanoparticles (GNPs), silicon carbide (SiC), and hydroxyapatite (HAp), and their effects on improving wear, corrosion resistance, and mechanical strength. Among these, CNTs emerge as a standout reinforcement due to their ability to enhance multiple properties when used at optimal weight fractions. Further, this study delves into the interaction between reinforcement types and matrix materials, emphasizing the importance of uniform dispersion in preventing porosity and improving durability. Optimal PM conditions, such as a compaction pressure of 450 MPa, sintering temperatures between 550 and 600 °C, and sintering times of 2 h, are recommended for achieving superior mechanical performance. Emerging trends in reinforcement materials, including nanostructures and bioactive particles, are also discussed, underscoring their potential to widen the application spectrum of Mg-MMCs. Full article

This study presents a comparative analysis of the corrosion and mechanical properties of an Al-SiC composite and an AA 2024 aluminum alloy, focusing on their suitability for aeronautical applications. The Al-SiC composite was fabricated using advanced powder metallurgy techniques, incorporating a 20% volume of silicon carbide (SiC) particles, averaging 1.6 µm in size, to enhance its structural and electrochemical performance. Electrochemical evaluations in an aerated 3.5% NaCl solution revealed a significant improvement in the corrosion resistance of the Al-SiC composite. This enhancement is attributed to the cathodic nature of the SiC particles, which promote the formation of a protective aluminum oxide layer, reducing pitting corrosion and preserving the material’s structural integrity. In terms of the mechanical properties, the Al-SiC composite demonstrated a higher yield strength and ultimate tensile strength compared to the AA 2024 alloy. While it exhibited a slightly lower elongation at failure, the composite maintained a favorable balance between strength and ductility. Additionally, the composite showed a higher Young’s modulus indicating improved resistance to deformation under load. These findings underscore the potential of the Al-SiC composite for demanding aerospace applications, offering valuable insights into the development of materials capable of withstanding extreme operational environments. Full article

The high-energy ball milling process was applied to fabricate a composite material from 7075 aluminium alloy milling chips, silicon carbide, and titanium dioxide powders. Raw materials were ground, and the obtained powders were cold pressed and sintered. It was demonstrated that this method can be used in the recycling of aluminium alloy scrap characterised by a high surface-to-volume ratio, and also that chemical removal of the oxide layer from chips is not necessary. The finest particles, with 50 vol.% of their population below 36 μm, were obtained after grinding for 60 min at a 1000 rpm rotational speed. Such an intensive grinding was necessary to fabricate the compact composite material with a homogeneous microstructure and a low porosity of 0.7%. The corrosion resistance of the composites was studied in 3.5 wt.% NaCl solution using cyclic voltammetry and electrochemical impedance spectroscopy, and corrosion rates in the range of ca. 342 and 3 μA∙cm⁻² were obtained. The corrosion mechanism includes aluminium alloy dissolution at the matrix/reinforcement interphase and around intermetallic particles localised within the matrix grains. Full article

Aluminum-based hybrid nanocomposites, namely the Al6061 alloy, have gained prominence in the scientific community due to their unique properties, such as high strength, low density, and good corrosion resistance. The production of these nanocomposites involves incorporating reinforcing nanoparticles into the matrix to improve its mechanical and thermal properties. The Al6061 hybrid nanocomposites were manufactured by conventional powder metallurgy (cold pressing and sintering). Ceramic silicon carbide (SiC) nanoparticles and carbon nanotubes (CNTs) were used as reinforcements. The nanocomposites were produced using different reinforcement amounts (0.50, 0.75, 1.00, and 1.50 wt.%) and sintered from 540 to 620 °C for 120 min. The characterization of the Al6061 hybrid nanocomposites involved the analysis of their mechanical properties, such as hardness and tensile strength, as well as their micro- and nanometric structures. Techniques such as optical microscopy (OM) and scanning electron microscopy (SEM) with electron backscatter diffraction (EBSD) were used to study the distribution of nanoparticles, the grain size of the microstructure, and the presence of defects in the matrix. The microstructural evaluation revealed significant grain refinement and greater homogeneity in the hybrid nanocomposites reinforced with 0.75 wt.% of SiC and CNTs, resulting in better mechanical performance. Tensile tests showed that the Al6061/CNT/SiC hybrid composite had the highest tensile strength of 104 MPa, compared to 63 MPa for the unreinforced Al6061 matrix. The results showed that adding 0.75% SiC nanoparticles and CNTs can significantly improve the properties of Al6061 (65% in the tensile strength). However, some nanoparticle agglomeration remains one of the challenges in manufacturing these nanocomposites; therefore, the expected increase in mechanical properties is not observed. Full article

The primary characteristic of ablative materials is their fire resistance. This study explored the development of cost-effective ablative materials formed into application-specific shapes by using a polymer matrix reinforced with ceramic powder. A thermoplastic (polypropylene; PP) and a thermoset (polyester; UPE) matrix were used to manufacture ablative materials with 50 wt% silicon carbide (SiC) particles. The reference composites (50 wt% SiC) were compared to those with 1 and 3 wt% short glass fibers (0.5 mm length) and to composites using a 1 and 3 wt% glass fiber mesh. Fire resistance was tested using a butane flame (900 °C) and by measuring the transmitted heat with a thermocouple. Results showed that the type of polymer matrix (PP or UPE) did not influence fire resistance. Composites with short glass fibers had a fire-resistance time of 100 s, while those with glass fiber mesh tripled this resistance time. The novelty of this work lies in the exploration of a specific type of material with unique percentages of SiC not previously studied. The aim is to develop a low-cost coating for industrial warehouses that has improved fire-protective properties, maintains lower temperatures, and enhances the wear and impact resistance. Full article

Laser additive manufacturing with mixed powders of aluminum alloy and silicon carbide (SiC) or boron carbide (B₄C) is investigated in this experiment. With various mixing ratios of SiC/Al to form metal matrix composites (MMC), their mechanical and physical properties are empirically investigated. Parameters such as laser power, scan speed, scan pattern, and hatching space are optimized to obtain the highest density for each mixing ratio of SiC/Al. The mechanical and thermal properties are systematically investigated and compared with and without heat treatment. It shows that 2 wt% of SiC obtained the highest strength and Young’s modulus. Graded composite additive manufacturing (AM) of MMC is also fabricated and characterized. Various types of MMC devices, such as heat sink using graded SiC MMC and grid type three-dimensional (3D) neutron collimators using boron carbide (B₄C), were also fabricated to demonstrate their feasibility for applications. Full article