Silicon 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.

Low-Velocity Impact Behaviors of B4C/SiC Hybrid Ceramic Reinforced Al6061 Based Composites: An Experimental and Numerical Study

This study studied the low-velocity impact behavior of silicon carbide (SiC), boron carbide (B4C), and hybrid B4C/SiC reinforced aluminum 6061 alloy (Al 6061) matrix composites experimentally and numerically. The effect of hybridization, reinforcement volume fraction, and reinforcement type on low-velocity impact was investigated. 16 different metal-matrix composite materials were manufactured for the study, including 9 hybrid samples, 6 non-hybrid samples for each reinforcing ceramic particle, and 1 unreinforced sample. The powder metallurgy - hot press method was used in experimental production and then low-velocity impact tests were carried out. Numerical study was carried out using the non-linear finite element method (FEM). A Python algorithm running on ABAQUS/Explicit was utilized to determine ceramic particle distribution based on volume fraction, hybridization ratio, and random particle arrangement. The Johnson-Cook Plasticity Model was used for the non-linear relationship between stress and strain in the Al 6061 metal-matrix during impact. The results were interpreted with the contact force-time, contact force-displacement, and energy-time data obtained from low-velocity impact tests. In addition, the amount of collapse that occurred during the impact was measured and compared, and finally, SEM/EDX analysis was performed for the microstructure characterizations of the composite sample. Impact tests revealed that the collapse of composite samples ranged from 3.06mm to 3.58mm, with the unreinforced S6 sample collapsing 4.18mm, indicating that increased reinforcement elements reduce ductility, while a lower B4C ratio or higher SiC ratio in hybrid composites leads to greater collapse. Keeping the hybridization rate constant while increasing the reinforcement ratio leads to an increase in contact force and a decrease in contact time. Hybrid composites exhibited higher stiffness as SiC content increased, while B4C reinforced non-hybrid composites showed more significant stiffness. There is good agreement between the numerical and experimental results. Non-hybrid samples have a better match between numerical predictions and experimental results than hybrid samples.

CORROSION BEHAVIOUR OF ADVANCED COMPOSITES CONTAINING SURFACE MODIFIED SIC AS REINFORCEMENT

The interface structure, micro-voids, pits, delamination, intermetallic compounds and internal stresses are the utmost critical factors influencing the corrosion performance of composite materials making them unsuitable for use in structural applications. One useful technique to control such adverse effect in composites is surface modification of the reinforcement. The present investigation involved the implementation of chemical techniques, particularly electroless plating (EP), to modify the surface of silicon carbide (SiC) particles by depositing a layer of nickel phosphorous (Ni-P) onto them. These plated SiC particles were subsequently employed in the production of Al/Ni-pSiC composites using the powder metallurgy (PM) method, with different weight percentages of plated SiC content ranging from 5% to 15%. The corrosion behaviour was assessed by potentio-dynamic polarization tests in 3.5% NaCl solution at room temperature. Results confirmed that AlNi-pSiC composites exhibit a greater resistance to pitting, in contrast to pure aluminium and Al/SiC composites without plating. The enhanced corrosion resistance in Al/Ni-pSiC composites can be attributed to strong interfacial bond, grain refinement, CTE difference, formation of Ni3Al, and reduced potential difference.

Assessment of impact load effect on self-sensing of cement composites incorporating hybrid silicon carbide-graphite under various environmental conditions

This study investigates the self-sensing abilities of hybrid silicon carbide-graphite cement composites (HSCGC) under various environmental conditions, focusing on dynamic impacts. Integrating silicon carbide (SiC) and graphite enhances the mechanical and electrical properties of these composites. Tests showed that composites with 30 % SiC and 2 % graphite had a 14.1 % increase in compressive strength and up to 85 % decrease in electrical resistivity. Water absorption reduced by 3.25 %, indicating better durability. Impact resistance ratios (IRR) varied with humidity and impact angles, with the highest IRR observed at 70 % humidity and a 30-degree angle. Self-sensing responses indicated that higher SiC and graphite content maintained stable conductivity, especially at 60 and 90-degree angles. Temperature changes affected resistivity, negligible at −10°C and increased at 45°C. The study concludes that HSCGCs are suitable for smart construction materials, capable of real-time environmental and structural monitoring, advancing predictive models and control systems.

Enhanced SiC/NFG/Ni ternary composite microwave absorbing materials with micro-network structures produced by selective laser sintering

In this paper, a ternary composite wave-absorbing material consisting of silicon carbide (SiC), natural flake graphite (NFG) and nickel (Ni) has been successfully fabricated through a combined process of selective laser sintering (SLS) and vacuum pressure impregnation. The study investigated how the content of SiC powder affected the absorption capacity and mechanical performances of the composites. The findings indicate that as the proportion of SiC powder rises, the porosity of the composites diminishes, while the bending strength increases. As the content of SiC is 40 wt%, the porosity is 52.14 % and the flexure strength is 9.58 MPa, approximately five times greater than that of graphite-type ceramic preforms. The composite’s electromagnetic wave-absorbing capability initially improves and then declines with the increase of SiC content. When the SiC content is 10 wt% and the thickness is 1.5 mm, the composite absorbing material exhibits optimal electromagnetic absorption performance, with a minimum reflection loss (RLmin)of −44.04 dB and an effective absorption bandwidth (EAB) of 5.42 GHz (8.24–13.66 GHz). The composite material, characterized by its lightweight, high strength, and broad frequency range, shows promise for applications in microwave absorption technology.

Copper-Nickel/SiC composites for applications on contact electrodes

Novel copper-nickel matrix composites reinforced with silicon carbide (SiC) micro particles for metal contact applications were manufactured by powder metallurgy technology and were experimentally characterized. Cu and Cu alloys are commonly used as metal contact for either vacuum, oil, or SF6 in low-voltage circuit breaker devices, but their application in environments with the presence of oxygen is limited due to their tendency to form high-resistance copper oxides. Thus, the addition of Ni as an alloying element provides resistance to both humidity and several corrosive environments and increases the composites' hardness, mechanical strength, and wear resistance. Moreover, SiC was chosen due to its contribution to mechanical strength, mouldability, low production cost, and non-reactive nature at ordinary temperatures. Here, three SiC particle size distributions were considered, and it was found that the composites' physical properties are also dependent on the ceramic loading. After evaluating these properties, two specific SiC concentrations were potentially considered for electrode applications: 10 wt% and 20 wt%. The obtained hardness values are in the range of 55 – 65 HR30T which guarantees the necessary strength without detriment of the contact area whereas the welding is minimized. In addition to a homogeneous particle distribution in the solid material, specific wear resistance of ∼10-5 mm3N-1m-1 and electrical conductivities of ∼20 %IACS were obtained. Considering these parameters, Cu-Ni/SiC composites' performance is not compromised compared to commercial Ag/WC materials commonly used in metal contact applications.

Evaluation of the Mechanical Properties of Aluminium Hybrid Nano Composites Using Ultrasonic-Assisted Stir Casting Method and Reinforced with Nano-scale SiC and MoS2 Particles

The purpose of this research is to investigate the effects of adding large quantities of reinforcing agents specifically, 3% MoS2 along with different SiC concentrations 5%, 10%, and 15% to LM25 aluminium alloys. The goal of producing these composites was to improve the material characteristics of hybrid metal matrix composites (HMMCs) by the use of ultrasonic-assisted stir casting. The study looks at the possible benefits of using particulate materials to improve the mechanical properties of metallic composites, such as silicon carbide (SiC) and molybdenum disulphide (Mo­S2). The research assesses the impact of SiC and MoS2 Nano scale additions on the mechanical and structural characteristics of LM25 composites by experimental analysis. The results of mechanical property testing show significant improvements, especially when 15% of Nano-scale SiC is included. This is mainly because the Nano-scale SiC is evenly distributed throughout the host metal.

Synergistic SiC/Co3O4 composites for enhanced microwave-assisted benzene catalytic removal performance

Microwave-assisted catalysis is a promising technique for enhancing catalytic reactions through selective heating, potentially leading to improved reaction rates and energy efficiency. However, understanding the complex interactions between microwave absorption and catalytic performance in composite catalysts remains a challenge. In this study, Cobalt oxide(Co3O4)/silicon carbide(SiC) composite catalysts with varying SiC content were synthesized and characterized to investigate the relationship between their microwave absorption properties and catalytic performance. Quantitative analysis revealed that SiC and Co3O4 absorb microwave energy through relaxation polarization and magnetic loss mechanisms, respectively. Increasing SiC content enhanced the dielectric and magnetic loss capabilities of the composites, with the Co3O4/SiC composite containing 10 wt% SiC (Co3O4/SiC-10) exhibiting a dielectric loss tangent of 3.87 and a minimum reflection loss of −35dB. However, higher SiC content decreased the surface chemically adsorbed oxygen, surface oxygen mobility, and benzene adsorption capacity, weakening the catalytic activity under conventional heating. The Co3O4/SiC-10 sample achieved a significantly better balance between microwave absorption and catalytic performance, significantly outperforming the original Co3O4 sample under microwave irradiation. These founding establishes a quantitative research methodology that correlates dielectric loss tangent, reflection loss, and other crucial parameters with microwave absorption performance and further catalytic properties, providing insights for the rational design of catalysts that optimize both microwave absorption and catalytic activity.

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.

The optimization of mechanical properties of polypropylene/styrene butadiene rubber/silicon carbide nanocomposites using response surface methodology

AbstractPolypropylene is a useful and widely consumed thermoplastic with very good properties that can be mixed with a combination of rubber and nanoparticles in order to eliminate its shortcomings. In this paper, the simultaneous combination of both the toughening effect of styrene–butadiene rubber (SBR) and the reinforcing effect of silicon carbide (SiC) nanoparticles were investigated in polypropylene matrix. Mechanical properties (tensile and impact strength [TS and IS]) of compounds were analyzed using the central composite design approach in Design‐Expert software. With two factors for input variables of SBR and SiC weight percentages, and their five levels (5, 10, 15, 20, and 25) and (0, 1.5, 3, 4.5, and 6), respectively, the central composite design approach employs 11 experiments for creation of models and the analysis of variance investigations with two output responses of TS and IS. Statistical results revealed that SBR and SiC contents had a significant effect on TS, IS, and the microstructure of compounds, as confirmed by scanning electron microscopy and energy‐dispersive spectroscopy images. To maximize all mechanical properties simultaneously with desirability functions, TS and IS of the optimum sample were computed to be 21.98 MPa and 8.66 kJ/m2 in amounts of 13.45 and 2.80 weight percentage (wt%) of SBR and SiC, respectively.Highlights By increasing silicon carbide (SiC) in polypropylene/styrene–butadiene rubber (SBR), tensile strength decreases after a peak due to agglomeration effect. By increasing SiC in polypropylene/SBR, impact strength decreases after a peak due to agglomeration effect. By increasing SiC, the rubber particles' dimensions decrease according to scanning electron microscopy analysis. Simultaneous maximum of tensile strength and impact strength are 21.98 MPa and 8.66 KJ/m2, respectively. Optimum value of SBR and SiC in above maximums are 13.45 and 2.8 wt%, respectively.

Microstructure, mechanical properties and wear behavior of Mg matrix composites reinforced with Ti and nano SiC particles

This study examines the mechanical properties and wear mechanisms of magnesium (Mg) metal matrix composites reinforced with titanium (Ti) and silicon carbide (SiC) particles. Three different composite formulations were investigated: Mg-30 wt% Ti (A), Mg-25 wt% Ti-5 wt.% SiC (NB), Mg-20 wt% Ti-10 wt% SiC (NC), and Mg-15 wt% Ti-15 wt% SiC (ND). These composites were fabricated through ball milling and spark plasma sintering (SPS). The incorporation of SiC particles significantly enhanced grain refinement and phase formation within the composites. Density analysis revealed that the actual densities of the composites were lower than the theoretical values, with Composite A exhibiting the highest actual density of 2.15 g/cm³ and the lowest porosity of 16.31%. The introduction of SiC particles increased porosity, with Composite NB displaying the highest porosity at 30.58%. Hardness testing indicated that Composite NC, containing 10 wt% SiC, achieved the highest hardness of 137 HV. In contrast, Composite ND, with 15 wt% SiC, showed a reduced hardness of 115 HV, attributed to increased porosity and potential SiC particle agglomeration. Wear behavior was evaluated using a pin-on-disc tribometer. Weight loss measurements indicated that Composite A had the lowest weight loss (1.1–2.1 mg), while Composite NB experienced the highest weight loss (2.8–8.3 mg) due to increased porosity. Composite NC demonstrated a balance with moderate weight loss (2.0–3.8 mg). The coefficient of friction (COF) varied with SiC content and applied loads (2, 4, and 8 N), with Composite A demonstrating the lowest COF values (2.3–2.8) and stable performance across different loads. Composite NB exhibited higher COF values (3.5–4) and significant fluctuations due to elevated porosity and the presence of SiC particles. Composite NC showed better wear resistance and more stable COF values (2.5–2.9) compared to NB and ND.

Reinforcing poly(lactic acid)/poly(butylene succinate) biodegradable blends with silicon carbide (SiC): A silane‐coupled approach for enhanced mechanical and thermal performance

AbstractThis study aims to enhance the properties of biodegradable plastics by blending poly(lactic acid) (PLA) as well as poly(butylene succinate) (PBS) with silicon carbide (SiC). SiC content was varied from 10 to 40 phr using an internal mixer, maintaining a 90/10 wt% ratio of PLA/PBS as the matrix. The investigation covered mechanical, thermal properties, chemical structure, and composite morphology. The morphological analysis confirmed even dispersion of SiC within the PLA/PBS matrix, possibly due to improved compatibility via a silane coupling treatment. This resulted in the maximum Young's modulus and impact strength with 40 phr SiC, showing a 40% and 76% enhancement, respectively, compared to pure PLA. Concerning thermal properties, SiC addition influenced the mobility of PLA/PBS molecular chains and crystalline structure, leading to an increase in Tg with higher SiC fractions. However, ΔHm of PLA, PBS, and Xc,PLA decreased, which corresponds to reduced viscosity in the PLA/PBS blend and increased mobility with higher SiC content, as indicated by the elevated MFI value.Highlights Young's modulus increased by 40% and impact strength by 76% than pure PLA. Even SiC dispersion in PLA/PBS, possibly aided by silane coupling. SiC alters chain mobility, boosts crystalline structure, raising Tg. ΔHm and Xc,PLA reduced, suggests reduced viscosity in PLA/PBS at more SiC. Elevated MFI value shows increased chain mobility in PLA/PBS blend at more SiC.

Electromagnetic wave absorption characteristics of silicon carbide modified concrete applied to protective engineering

Electromagnetic protection measures can effectively prevent electromagnetic waves from harming equipment, facilities, information security and human health. To enhance the electromagnetic wave-absorbing capacity of standard concrete, silicon carbide (SiC) was selected as an absorbing agent to produce wave-absorbing concrete. The influences of SiC content on the electromagnetic reflection loss, electromagnetic parameters, and mechanical properties of concrete were systematically investigated. After 28 days of curing, the concrete sample modified with 10 wt% SiC displays the compressive strength and splitting tensile strength of 36.12 MPa and 3.10 MPa, respectively. And the optimum electromagnetic absorption performance reaches −16.25 dB at 3.37 GHz and the electrical conductivity is 1.55×10−4 S/m. The SiC modified concrete demonstrates the dielectric loss type absorption characteristics. This research provides a practical solution for electromagnetic wave protection, which is expected to be used in both military and civilian applications.

Effect of residual carbon on silicon carbide ceramics in photopolymerization-based additive manufacturing

Silicon carbide (SiC) is widely used in various industrial fields for its excellent properties. Vat photopolymerization (VP) technology stands out in the fabrication of SiC ceramics due to its enhanced design flexibility and capability to produce intricate geometries. However, the excessive residual carbon content in VP technology directly affects the sintering performance of SiC ceramics, leading to cracking and deformation defects. To address this issue, we systematically studied the residual carbon content of SiC under different debinding atmospheres in forming by VP technology. We found that the debinding atmosphere can effectively control the residual carbon content in SiC ceramics. Residual carbon exists in samples with a lower degree of defect, promotes grain growth, reduces neck size, and results in flexural strength of 253.13 MPa after pressureless sintering. This research promotes the application of VP technology in SiC ceramics and opens up a new avenue for the development of high-performance SiC ceramics.

Investigating the valence balance of adding Nano SiC and MWCNTs on the improvement properties of copper composite using mechanical alloying and SPS techniques

This study presents a comprehensive investigation of copper-based nanocomposites reinforced with silicon carbide (SiC) nanoparticles and multi-walled carbon nanotubes (MWCNTs). The manufacturing procedure involved powder metallurgy techniques followed by spark plasma sintering (SPS). Microstructural analysis revealed a notable reduction in particle size (from 23.72 μm to 18.31 μm) and crystallite size (from 104.32 nm to 87.36 nm) with the addition of reinforcements. The bulk microstructure exhibited a reduction in grain size by approximately 13.1 %. XRD analysis confirmed the absence of new phases. Evaluation of SPS parameters demonstrated varying density and porosity, with the highest relative density of 99.96 % observed in pure copper composites. Hardness measurements indicated that surface hardness surpassed cross-sectional values, with the lowest recorded value being 64.79 HV for composite Cu-5%SiC-1%MWCNTs (S4). Wear rate analysis revealed an increase, with pure copper composites exhibiting a wear rate of 1.78 × 10^-4 mm3/m, while composite S4 displayed a rate of 3.25 × 10^-4 mm3/m under a load of 5 N. Coefficient of Friction (COF) exhibited significant fluctuations, influenced by the applied load and composite composition. Thermal conductivity decreased with higher SiC and MWCNT content, with sample S1 exhibiting the highest thermal conductivity among reinforced composites. Electrical conductivity trends were influenced by the type and concentration of reinforcing particles, resulting in an increase of approximately six times in composite S4 compared to the pure sample.

THE EFFECT OF MODIFICATION WITH HIGHLY DISPERSED SILICON CARBIDE ON THE MECHANICAL PROPERTIES AND DENSITY OF THE SECONDARY ALUMINUM ALLOY OF THE AL-SI SYSTEM

The effect of modification on the mechanical properties of the secondary aluminum casting alloy (wt.%: 0,528 Mg, 1,124 Cu, 11,539 Si, 84,969 Al, 0,905 Fe, 0,692 Zn, 0,242 Mn) without heat treatment was determined by the introduction of silicon carbide with a particle size of 1-3 μm in the amount of 0.1, 0.2, 0.3 wt. %. Castings were made in steel molds. It is established that the strength of unmodified alloy (σв) is 110 - 120 MPa. When the content of SiC in the alloy from 0.1% to 0.2%, the indicators of σв increase from 130-145 MPa to 155-166 MPa, respectively. Increasing the SiC content to 0.3% leads to a decrease in σв values in the range of 117 - 127 MPa. Hardness indices (HВ): unmodified alloy - 42 - 43, alloy with a content of 0.1% SiC - 43 - 44, with a content of 0.2% SiC - 46 - 47, with a content of 0.3% SiC - 43 - 44. Determination of the density of cast metal obtained in a steel mold and in a sandy-clay form was carried out by the method of hydrostatic weighing of samples in СCl4. It has been established that the density of the alloy of castings with a silicon carbide content of 0.1% is 2761 kg/m3, and that of the unmodified alloy is 2715 kg/m3. With an increase in the silicon carbide content to 0.2%, the density of the metal is 2735 kg/m3. With a SiC content of 0.3 wt.%, the density of the alloy is 2752 kg/m3. The density of the metal of the castings obtained in the sandy-clay form with the modification of 0.1% SiC is 2673 kg/m3, with 0.3% SiC - 2676 kg/m3.

Analysis of the structure of electrically conductive composite ceramics

The object of the research is electrically conductive ceramics. It aims to analyze the microstructure of electrically conductive ceramic composites based on silicon carbide and investigate the influence of silicon carbide content on their properties. This study is pivotal for enhancing materials used in high-tech applications, particularly in fields where distinct electrical insulation and mechanical characteristics are crucial. The microstructure analysis conducted through scanning electron microscopy confirmed the presence of silicon carbide in all examined ceramic samples, except in those where silicon carbide was not added. Special attention should be given to the sample with 30 % silicon carbide, distinguished by the lowest open porosity. These findings are corroborated by previous research where this sample exhibited superior properties: open porosity – 12.51 %, water absorption – 5.88 %, apparent density – 2.13 g/cm³, specific resistance – 0.43·106 Ω·m. These characteristics indicate low porosity and high structural-physical property values. The results not only affirm the successful incorporation of silicon carbide into the ceramic matrix but also highlight the prospects for applying the researched ceramic materials in areas where electrical insulation and mechanical properties are crucial. Specifically, the sample with 30 % silicon carbide appears particularly promising due to its high characteristics and lower porosity, making it potentially interesting for applications in high-tech industries such as electronics and telecommunications. The conclusions suggest the potential use of these ceramic materials in various high-tech industries where both electrical and mechanical properties are essential. The sample with 30 % silicon carbide, with its exceptional characteristics, holds potential for applications in advanced technologies. Further research in this direction could lead to the development of new materials for effective radiofrequency absorption, finding broad applications in different technological fields.

The effect of SiC on the growth habit of Fe-Ni-C system Ib gem grade diamond crystals

This article investigates the influence of different silicon carbide contents on the morphology and quality of diamond single crystals synthesized in the Fe-Ni-C-Si system under high temperature and pressure environments. It was found that silicon successfully entered the diamond lattice through bonding. As the doping concentration increases, the growth rate of diamond crystals decreases and defects appear on the crystal surface. The increase in internal stress in the lattice reduces the quality of diamond, as evidenced by the shift in Raman peak and half peak width of the diamond. Moreover, the infrared characterization results showed that the nitrogen element in the crystal exists as a single atom (C-center) in the diamond crystal, and the nitrogen content decreases with the increase of SiC content. This work provides insights for understanding the growth mechanism of natural diamonds and enriching the application of silicon doped diamond single crystals.

Effect of Milling Time and Reinforcement Volume Fraction on Microstructure and Mechanical Properties of SiCp-Reinforced AA2017 Composite Powder Produced by High-Energy Ball Milling.

The influence of milling time and volume fraction of reinforcement on the morphology, microstructure, and mechanical behaviors of SiCp-reinforced AA2017 composite powder produced by high-energy ball milling (HEBM) was investigated. AA2017 + SiCp composite powder with different amounts of SiC particles (5, 10, and 15 vol%) was successfully prepared from gas-atomized AA2017 aluminum alloy powder with a particle size of <100 μm and silicon carbide (SiC) powder particles with an average particle size of <1 μm. An optical microscope (OM), X-ray diffraction (XRD), and scanning electron microscope (SEM) were utilized to characterize the microstructure of the milled composite powder at different milling periods. The results indicated that the SiC particles were homogeneously distributed in the AA2017 matrix after 5 h of HEBM time. The morphology of the particles transformed from a laminar to a nearly spherical shape, and the size of the milled powder particles reduced with increasing the content of SiC particles. The XRD analysis was carried out to characterize the phase constituents, crystallite size, and lattice strain of the composite powders at different milling periods. It was found that with increasing milling time and SiC volume fraction, the crystallite size of the aluminum alloy matrix decreased while the lattice strain increased. The average crystallite sizes were reduced from >300 nm to 68 nm, 64 nm, and 64 nm after 5 h of milling, corresponding to SiC contents of 5, 10, and 15 vol%, respectively. As a result, the lattice strain increased from 0.15% to 0.5%, which is due to significant plastic deformation during the ball milling process. XRD results showed a rapid decrease in crystallite size during the early milling phase, and the minimum grain size was achieved at a higher volume fraction of SiC particles. Microhardness tests revealed that the milling time has a greater influence on the hardness than the amount of SiC reinforcements. Therefore, the composite powder milled for 5 h showed an average microhardness three times higher than that of the unmilled powder particles.

A Selective Separation of Platinum Group Metals from the Fe-PGM Alloy Using Electrodeposition Combined with Electrochemical Dealloying

In the European automotive industry, a considerable volume of recalled car catalysts stems from diesel vehicles, characterized by their high silicon carbide (SiC) content. Processing such materials poses notable challenges compared to gasoline vehicle catalysts. The presence of SiC demands additional time and energy in electric arc furnace processing, with SiC’s high melting point and strong reducing properties complicating separation. The Fe-PGM alloy obtained after pyrometallurgical treatment of these SiC-rich catalysts presents hurdles for hydrometallurgical processing. With high silicon content, the alloy resists corrosion in sulfuric acid, impeding solubility and hindering progress in the recovery process. This article explores an innovative approach for selectively extracting platinum group metals (Pt, Pd, Rh) from Si-rich Fe-PGM alloys. Traditional hydrometallurgical methods struggle due to the alloy’s near-immunity to acid leaching. The study presents chemical leaching results and proposes electrodeposition combined with electrochemical dealloying as a feasible solution. This method, aiming for selective metal separation, seeks to enhance recovery process profitability by producing pure metals.