SiC Composites Research Articles

Fabrication of dense Cf/SiC ceramic matrix composites using 3D printing and PIP with short carbon fibre as a toughening material

ABSTRACT To achieve weight reduction, toughness enhancement, and the fabrication of complex structures in SiC composites, a combination of SLS and PIP processes was used. Silicon carbide powder served as the matrix material, while short carbon fibres were used for toughening, resulting in dense Cf/SiC ceramic matrix composites. The effects of varying carbon fibre sizes and contents on the microstructure and mechanical properties of Cf/SiC composites were examined. Results indicated that adding 8% carbon fibre increased the fracture toughness of Cf/SiC composites by 33.33%. Further increases in carbon fibre content showed minimal effects on fracture toughness. Based on experimental results and finite element simulations, toughening mechanisms, including fibre pull-out, fibre debonding, and crack deflection, were further elucidated. Consequently, Cf/SiC composites with complex structures, such as turbine specimens and lattice structures, were successfully fabricated.

Wear properties of Al6061/SiC + B4C + TiC hybrid composites produced by vacuum infiltration method

Abstract In the study, hybrid metal matrix composite (HMMC) structures were produced by vacuum infiltration method (VIM) using Al6061 alloy and varying amounts of SiC, B4C, and TiC ceramic powder pairs. Age-hardening processes were applied to these HMMCs. After heat treatment, wear behavior was examined under different loads using the pin-on-disc test method. All Al6061 hybrid composites exhibited better wear performance than unreinforced Al6061. In the wear tests of composite samples, the lowest volume loss and therefore the highest wear resistance were obtained in Al6061 3 wt.% B4C + SiC composites under 5 N force. The lowest wear resistance due to the highest volume loss was determined in Al6061/1 wt.% TiC + B4C composites under 15 N force. Abrasive and adhesive wear characteristics were observed in field emission scanning electron microscopy(FESEM) images of worn surfaces. Additionally, wear debris, smearing, and deep grove formations were determined on the surface. In the EDS analysis performed on the worn surface, O and Fe elements were found in addition to the elements that are likely to be in the structure (such as Al, B, C, Ti, Si, and Mg). The wear tests caused the formation of oxide layers on the sample surfaces.

Fabrication, Microstructural Evolution, and Mechanical Properties of SiC/(Hf0.25Ta0.25Zr0.25Nb0.25)C/C Nanocomposites.

A dense monolithic SiC/(Hf0.25Ta0.25Zr0.25Nb0.25)C/C high-entropy ceramic nanocomposite was prepared using a polymer-derived ceramic (PDC) method combined with spark plasma sintering (SPS). The microstructural evolution and mechanical properties of the obtained nanocomposites were characterized by X-ray diffractometer (XRD), transmission electron microscope (TEM), scanning-electron microscope (SEM), and nanoindentation. The results indicate that the phase composition of SiC/(Hf0.25Ta0.25Zr0.25Nb0.25)C/C can be adjusted by modifying the metal content of the single-source precursor (SSP) through molecular design. The resulting precursor exhibits an exceptionally high ceramic yield, with mass retention of over 90% at 1100 °C, which guarantees the densification of the final SiC/(Hf0.25Ta0.25Zr0.25Nb0.25)C/C composites. The PDC route facilitates the in situ formation of a high-entropy phase within the ceramic matrix under low temperature pyrolysis conditions. Combined with SPS, a dense monolithic SiC/(Hf0.25Ta0.25Zr0.25Nb0.25)C/C nanocomposite was obtained, exhibiting an open porosity of 0.41 vol%, nano-hardness of 27.47 ± 0.46 GPa, elastic modulus of 324.00 ± 13.60 GPa, and fracture toughness of 3.59 ± 0.24 MPa·m0.5, demonstrating excellent mechanical properties.

Reactive Spark Plasma Sintering and Oxidation of ZrB2-SiC and ZrB2-HfB2-SiC Ceramic Materials

This study presents the fabrication possibilities of ultra-high-temperature ceramics of ZrB2-30 vol.%SiC and (ZrB2-HfB2)-30 vol.% SiC composition using the reaction spark plasma sintering of composite powders ZrB2(HfB2)-(SiO2-C) under two-stage heating conditions. The phase composition and microstructure of the obtained ceramic materials have been subjected to detailed analysis, their electrical conductivity has been evaluated using the four-contact method, and the electron work function has been determined using Kelvin probe force microscopy. The thermal analysis in the air, as well as the calcination of the samples at temperatures of 800, 1000, and 1200 °C in the air, demonstrated a comparable behavior of the materials in general. However, based on the XRD data and mapping of the distribution of elements on the oxidized surface (EDX), a slightly higher oxidation resistance of the ceramics (ZrB2-HfB2)-30 vol.% SiC was observed. The I-V curves of the sample surfaces recorded with atomic force microscopy demonstrated that following oxidation in the air at 1200 °C, the surfaces of the materials exhibited a marked reduction in current conductivity due to the formation of a dielectric layer. However, data obtained from Kelvin probe force microscopy indicated that (ZrB2-HfB2)-30 vol.% SiC ceramics also demonstrated enhanced resistance to oxidation.

High strength C/Si‒Ni‒C composites fabricated by reaction melt infiltration with Si‒Ni alloy at lower temperature

AbstractSilicon‒nickel alloy (Si‒Ni) was first used for fabricating continuous carbon fiber reinforced ceramic matrix composites by reaction melt infiltration process. Based on Si‒Ni phase diagram, 66.7 at.% Si‒Ni was chosen, which has a lower liquidus temperature of 1115°C. The C/Si‒Ni‒C composites were infiltrated at temperature of 1270°C‒1390°C, and the prepared composite consists of C, SiC, NiSi, and NiSi2 phases. The density of the composite is higher than 2.29 g/cm3 and their open porosity is below 3%, indicating the composite was infiltrated completely by the Si‒Ni alloy. The C/Si‒Ni‒C composite exhibits significantly higher flexural strength and fracture toughness compared to the C/C‒SiC composite infiltrated with pure silicon at 1500°C. Specifically, the flexural strength and fracture toughness of the C/Si‒Ni‒C composite infiltrated at 1390°C increase by 140% and 300%, respectively. The improvement of mechanical properties contributed to the low reactivity between silicon‒nickel with carbon fibers, and the lower infiltration temperature, which can reduce degradation of carbon fiber as reinforcement. Moreover, the NiSi2 and NiSi alloy phases in the C/Si‒Ni‒C composite replace the brittle silicon phase in the C/C‒SiC composite, which can obviously enhance the fracture toughness.

Microstructure and ablation behavior of C/C–HfC–SiC composites fabricated by reactive melt infiltration with Hf–Si alloy

AbstractC/C–HfC–SiC composites were prepared by reactive melt infiltration using Hf–Si alloy (Hf, more than 95 wt%) with a density of 3.86 g/cm3 and an open porosity of 8.34%. The microstructure, mechanical properties, and ablation behavior at high temperatures were studied in detail. SiC played a crucial role in alleviating the thermal mismatch between HfC and PyC, which formed at the interface between the carbon matrix and the HfC matrix. The flexural strength and modulus of C/C–HfC–SiC composites were 237 MPa and 37.6 GPa, respectively. The C/C–HfC–SiC composites exhibited excellent ablation resistance with a linear ablation rate of 8.9 × 10−3 mm/s and maintained a surface temperature above 2925°C during ablation. During this process, HfO₂ remained in a molten state with high viscosity and served as a thermal barrier, while the volatilization of SiO₂ effectively removed heat, protecting the composites from further ablation.

Boron nitride nanosheets composite SiC fibers with enhanced mechanical properties and high‐temperature resistance

Boron nitride nanosheets composite SiC fibers with enhanced mechanical properties and high‐temperature resistance

In situ synthesis, mechanical properties, and reaction mechanism of the WB2–SiC composites

AbstractIn the present work, WB2–SiC composite powders containing 20 vol.% of SiC were in situ synthesized by the boro/carbothermal reduction with WO3, SiO2, B4C, and carbon black as raw materials at 1400°C, 1500°C, and 1600°C, respectively. The as‐synthesized composite powders were then consolidated by spark plasma sintering (SPS) technique to obtain WB2–SiC composite bulk samples. The experimental results showed that the relative density of the WB2–SiC composite ceramic samples achieved in this study was higher than 97.5%. Also, electronic microscopy observations showed that SiO2 had reacted completely during the preparation process, and the SiC grains were homogenously embedded among the WB2 grains with the formation of a three‐dimensional structure. The Vickers hardness and fracture toughness values of the composite ceramic fabricated by powder heat treated at 1400°C were 24.6 ± 0.7 GPa and 5.4 ± 0.7 MPa·m1/2, respectively, which were the highest among three samples prepared in this study.

Reactive sintered dense carbon fiber reinforced high‐entropy boride composite using high‐entropy silicide as reactant

AbstractA novel reactive sintering strategy using high‐entropy disilicide, B4C, and carbon as initial materials is developed to fabricate dense carbon fiber reinforced high‐entropy diboride (HEB)‐based composite (Cf/HEBs) at a relatively low temperature. The Cf/(V0.2Nb0.2Cr0.2Mo0.2W0.2)B2–SiC composite (Cf/HEB–SiC) successfully achieves nearly full densification (with a relative density of 99.2%) at 1800°C. The reactive damage of carbon fibers can be effectively restrained by preassemble carbon coating during the preparation process of the composite. Lower preparation temperature and effective coating protection contribute to the exertion of carbon fibers toughening capacity, consequently noticeably elevating the critical crack size (αcr) from 27.7 µm for HEB–SiC to 110.4 µm for Cf/HEB–SiC. The current work provides a feasible way to substantially upgrade the damage tolerance of HEB–SiC and can be extended to other HEBs‐based ceramics.

Effect of a Zr source addition on the microstructure of Al-SiC composites elaborated by the Laser Powder Bed Fusion (L-PBF) process

The present work focuses on the effect of the addition of a zirconium source on the microstructure of Al-SiC composites produced by Laser Powder Bed Fusion (L-PBF). More specifically, the aim is to address the issue of the SiC decomposition into the water-soluble aluminum carbide Al4C3 in Al-SiC composites produced by L-PBF, with the objective of limiting its formation by adding another element to the system. To this end, AlSi7Mg0.6-SiC-ZrO2 composite powders are successfully prepared and printed in a standard L-PBF equipment. The resulting parts are then thoroughly characterized, in order to understand the physico-chemical mechanisms involved during the L-PBF process. The results show a decrease in the Al4C3 amount by ZrC formation. Another important result is that bulk composites exhibit a fully equiaxed microstructure attributed to the τ1 (Al,Si)3Zr ternary phase, with all the characteristics of a good nucleating agent for aluminum phase. To support these microstructure experimental results, a first version of a quaternary Al-Zr-Si-C thermodynamic database was developed using the Calphad method. These calculations enable to establish a solidification path providing information on the phases that may form after heat treatment of L-PBF materials.

Mechanical characterization of Al2219-SiC metal matrix composites

The present work conducted an experimental examination to assess the tensile behaviour and microstructural characteristics of Al2219 metal alloy reinforced with 4 and 8 wt. % of SiC composites. The investigation employed the liquid metallurgical method to fabricate composites of the Al2219 alloy including SiC particles at weight percentages of 4 and 8. This work employed supplementary methods, including scanning electron microscopy (SEM), to determine the microstructural characteristics. An investigation of the mechanical characteristics of Al2219 alloy with SiC reinforced composites is conducted in accordance with ASTM Standards. Furthermore, the incorporation of silicon carbide particles into aluminium 2219 demonstrates remarkable characteristics in the field of composite materials, therefore augmenting its potential for a broad spectrum of uses. Enhancements in hardness and tensile strengths of the composites were achieved by combining different materials. The fractured surfaces of the Al2219-SiC composites displayed both brittle and ductile fracture characteristics, as indicated by their tensile test results.

Exploring the Optimal Binder Content in Composite Electrodes for Sulfide-Based All-Solid-State Lithium-Ion Batteries

All-solid-state batteries (ASSBs) are promising next-generation batteries owing to their improved safety compared with lithium-ion batteries using flammable liquid electrolytes. Among various solid electrolytes, sulfide-based electrolytes exhibit high ionic conductivities, and their ductile properties allow them to be easily processed without high-temperature sintering. In sulfide-based ASSBs, a polymer binder is essential for achieving a good cycling performance by maintaining strong interfacial contacts in the composite electrodes during cycling. In this study, we prepared a composite Si-C anode and a LiNi0.82Co0.1Mn0.08O2 cathode using a nitrile-butadiene rubber binder for ASSB applications, and investigated the effect of the binder content on the mechanical properties and electrochemical performance. The binder content significantly influenced the physical and electrochemical characteristics of the composite electrodes, and the ASSB prepared with 1.5 wt% binder showed the best cycling performance considering capacity retention and rate capability. Furthermore, we investigated how the excess binder adversely affected the cycling performance through time-of-flight secondary ion mass spectrometry analysis.

Fabrication of carbon fiber reinforced SiC composites based on laser directed energy deposition

Carbon fiber reinforced silicon carbide ceramic matrix composites (CF/SiC) are widely applied in aerospace and other industries fields for its extraordinary properties. Nevertheless, traditional preparation processes encounter the challenges of long cyclicality, high economic cost due to the increasing requests. Consequently, this work integrates the CF/SiC composites with the novel laser directed energy deposition (L-DED) printing technology, which is differing from conventional 3D printing technology for it omits the post-processing procedure. CF/SiC composites are designed and manufactured efficiently, and the effects of carbon fiber addition are analyzed. Mechanical properties are utilized to characterize the internal bonding strength and the results reveal that the maximum flexural and compressive reach 119.33 ± 4.04 MPa and 396.20 ± 10.21 MPa, respectively, attributed to the enhanced crack propagation resistance caused by the carbon fiber addition. At the same time, this paper not only characterizes the performance through objective experimental data, but also expounds the formation mechanism of pores and cracks through material analysis. In conclusion, this work pioneers the application of L-DED molding technology to CF/SiC composites fabrication and validated its preparation capability, which not only improves the efficiency but also opens up a new path for CF/SiC composites preparation in the field of 3D printing.

Microstructure evolution and mechanical response of hetero-induced SiCp addition in Al-6061 under high strain rate compressive loading

Al/SiC composites having a high-volume fraction of SiC are eye-catching materials in the automobile and aerospace industries. However, their behavior under stringent environments i.e., under high strain rate compression is much different than quasi-static compression. For such conditions, the morphology, interfacial bonding, and the fraction of the SiC play a decisive role in achieving the high performance of the Al/SiC composites. Here, in this study, we reported that a transitional effect of de-bonding and intergranular crack in SiC has occurred in Al–SiC composites having SiC particle size >0.7 μm. Below the 0.7 μm, the diffusion of the Al dislocations is characterized on the boundary of SiC along with the strong interfacial bonding. To prove it, we have fabricated an Al6061/30 vol% SiC composite through powder metallurgy route and subsequently subjected to compression in the range of strain rate 0.001–2100 s−1. In support of our observations, the microstructure was characterized by optical microscopy, scanning electron microscopy, X-ray diffraction, electron backscattered diffraction, and transmission electron microscopy analysis. The result also revealed a positive strain rate sensitivity up to a strain rate of 1800 s−1, while for 2100 s−1, the flow stress decreased, which is the cause of adiabatic temperature rise, dynamic recrystallization in Al, and massive cracks and deboning in coarse SiC particles. We also characterized that the SiC having particle size 1–4 μm showed stacking fault and dislocation induced in the SiC due to strong interfacial bonding. A quantitate analysis of dislocation was also established by using the Williamson-Hall technique which further confirmed the dislocation activity and dynamic recrystallization in 2100 s−1, characterized by EBSD and TEM. Thus, this study enables our understating that using the fine SiC particles is promising for achieving the high performance of the Al/SiC composites for use in stringent environments.

Surface roughness prediction model and surface topography analysis of 2.5D-Cf/SiC in two-dimensional ultrasonic assisted grinding based on GA-BP neural network

Because of the anisotropy and non-uniformity, the grinding surface quality of Cf/SiC composites is difficult to be accurately predicted. To better predict the surface quality of 2.5D-Cf/SiC composites, the BP neural network was optimized by genetic algorithm (GA), and the surface roughness prediction model of fiber orientation, ultrasonic amplitude, and machining parameters was established. The empirical formula prediction model of surface roughness was established by the method of multiple linear regression analysis. The results show that the prediction accuracy of GA optimized BP neural network is the best, followed by the empirical formula, and the prediction effect of the BP neural network is the worst. The average absolute percentage error of these three models is 10.045 %, 16.912 % and 26.6245 % respectively. The kinematic models of conventional and two-dimensional ultrasonic-assisted grinding of single particles were established respectively. Based on the kinematic model, the reasons for the reduction of surface roughness by 2D ultrasonic-assisted grinding are explained. According to the orthogonal test results, the surface roughness decreases the most when vs is 0.66 m/s, vw is 100 mm/min, ap is 150 µm along the fiber orientation of 0°, and the maximum percentage of reduction is 53.18 %. Increasing the linear speed, reducing the feed speed, reducing the grinding depth, and applying ultrasound can reduce the extrusion pressure along the axis of 0° fiber, and then reduce the length and depth of cracks and thus reduce the surface defects. The axial shear force of the 90° oriented abrasive particles on the fiber is reduced, thus reducing the surface damage caused by torsional deformation. Reduce 3D surface profile and improve surface quality. The maximum percentage reduction of each parameter index is as follows: root mean square height decreased by 28.8 %, skew decreased by 88.61 %, kurtosis decreased by 48.97 %, maximum crest height decreased by 48.55 %, maximum sag height decreased by 40.09 %, maximum height decreased by 43.93 %, and arithmetic mean height decreased by 26.06 %.

Ablation behavior of Cf/ZrC–SiC ultra–high temperature ceramic composites in oxyacetylene torch and plasma wind tunnel

Ablation performance of Cf/ZrC–SiC composites was evaluated in both oxyacetylene torch and plasma wind tunnel and further comparative study was conducted on the ablation behavior under two environments. An oxyacetylene torch test led to a pitting corrosion of Cf/ZrC–SiC composites and their ablated surface was covered by a porous zirconia layer. The Cf/ZrC–SiC nose tip endured the plasma wind tunnel test rather well with only 0.43 % height loss after total 1050 s exposure due to the formation of a compact zirconia scale. This compact zirconia scale kept its consolidation to the composite body and acted as the ablation-resistant and thermal shielding layer of the nose tip.

Robust anti-icing double-layer superamphiphobic composite coatings for heat exchangers

The formation and accumulation of ice on the heat exchangers of air conditioners significantly reduce the performance issues, as well as the stability and heating efficiency. Superhydrophobic anti-icing coatings passively achieve multifunctional anti-icing properties by minimizing water droplet contact and promoting Cassie ice formation. However, long-term performance in frigid environments remains challenge for these coatings due to limitations in anti-icing durability and mechanical properties. Herein, a double-layer polymer-SiC/F-SiO2 superamphiphobic composite coating is developed. The bottom layer comprises a polymer PAI and SiC composite, and the top layer consists of F-SiO2. The composite coating demonstrates superior performance in simultaneous frost prevention, low ice adhesion, easy frost removal, exceptional mechanical strength, and long-lasting anti-icing durability. Our developed double-layer coating exhibits low ice adhesion strength down to 9.2 kPa, remarkable mechanical resilience against scratching and flushing, and delayed frost properties. These superior anti-icing properties, manifested by both lower adhesion strength and improved frost repellency, lead to a doubling of frosting time and the easier removal of ice on coated heat exchangers compared to traditional units. The development of this novel superamphiphobic composite coating provides a practical approach to creating durable anti-icing materials, leading to significant improvements in air conditioner performance.

Phase formation, microstructure and mechanical properties of TaB2–SiC composites synthesized by reaction hot pressing: Effects of SiC contents and oxygen impurity

TaB2–SiC composites with 0–20 wt% SiC contents were prepared by reaction hot pressing using Ta, B and SiC powders as starting materials. Densification, constituent phases, microstructure and mechanical properties, namely Vickers hardness, fracture toughness and flexure strength, were evaluated by means of inspection of sintering shrinkage, density measurement, XRD, SEM, TEM, HRTEM, EDS, SAED, indentation and three-point bending tests. Phase formation, including dominant (TaB2, SiC) and minor (TaC, glassy SiO2) phases, was checked by thermodynamic assessment relevant with Ta2O5 and B2O3 impurities introduced into the reaction system by the starting powders. The results showed that mixtures of Ta, B and SiC powders would initiate self-propagating combustion synthesis (SPCS) at about 900 °C; a transient hold at 800 °C for 1 h could suppress this reaction. Volatilization of B2O3 impurity in association with local high temperature due to SPCS helped reduce the TaC and glassy SiO2 minor phase formation. TaB2–SiC composites could reach 99 % relative densities with 3 wt% SiC addition and above. Compositions with <7.5 wt% SiC additions showed uniform dispersion of SiC particles at multi-TaB2 grain junctions while compositions with higher SiC content revealed SiC segregation. Bending strength of 503 MPa and fracture toughness of 6.69 MPa⋅m1/2 could be reached with 7.5–20 wt% SiC addition.

Development of cellulose acetate poly acrylonitrile (CAPA)–SiC/epoxy coating to mitigate corrosion of copper in chloride containing solutions

A new conducting polymer of the cellulose acetate poly acrylonitrile (CAPA)–SiC composite was produced using an in situ oxidative polymerization technique in an aqueous medium. SiC was synthesized from Cinachyrella sp. as a source of carbon and silicon at 1200 °C under an argon atmosphere via a catalytic reduction process. The structure and morphology of the CAPA–SiC composite were characterized using surface area studies (BET), X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FT-IR), and surface morphology (SEM & TEM). To protect copper, the produced CAPA–SiC composite was mixed with commercial epoxy paint using a casting technique, and the copper surface was coated with the three components of the CAPA–SiC/epoxy paint mixture. The corrosion inhibition improvement of the CAPA–SiC/paint coating was assessed using electrochemical impedance spectroscopy followed by Tafel polarization measurements in a 3.5 wt% NaCl solution. The corrosion protection ability of the CAPA–SiC/epoxy coating was found to be outstanding at 97.4% when compared to that of a CAPA/paint coating. SEM and XRD were used to illustrate the coating on the copper surface.

Predictive modeling of MRR, TWR, and SR in spark-EDM of Al-4.5Cu–SiC using ANN and GEP

In this study, Al-4.5Cu alloy was reinforced with varying weight percentages of SiC particles (2%, 4%, 6%, and 8%) to create metal matrix composites via the stir casting method. The formation of intermetallic compounds was confirmed through energy dispersive spectroscopy and x-ray diffraction analysis. This article compares the performance of Artificial Neural Network (ANN) and Gene Expression Programming (GEP) models in predicting the Metal Removal Rate (MRR), tool wear rate, and surface roughness in the die-sinking electro-discharge machining (EDM) process of the ex-situ developed Al-4.5%Cu–SiC composites. The study considers three machine parameters—pulse on time (TON), pulse off time (TOFF), and current (I)—along with the weight fraction of SiC particles as input variables for the models. Both ANN and GEP models demonstrated high predictive accuracy for the EDM performance metrics, with correlation coefficients (R) ranging from 0.973 68 to 0.980 65 for the ANN model and 0.980 11 to 0.982 59 for the GEP model. Notably, the GEP model exhibited superior predictive capability, as evidenced by its higher correlation coefficients and lower root mean square error, indicating greater effectiveness in predicting the EDM process outcomes than the ANN model.