Silicon Carbide Ceramics Research Articles

Erosion model of silicon carbide ceramics and YW3

In this study, an erosion model of silicon carbide ceramics and YW3 was established by combining experimental and numerical simulation data. This model can be applied for the prediction of erosion in natural gas equipment and transportation systems and also provides ideas for the establishment of erosion models. The erosion model was established by using quartz sand, brown corundum, and glass beads as abrasive materials, and then the accuracy of the erosion model was confirmed by numerical simulations. The results showed that when the abrasive was quartz sand, brown corundum, or glass beads, the erosion angle at which the maximum erosion of silicon carbide and YW3 occurred was related to the type of abrasive. When the abrasive was quartz sand, brown corundum, and glass beads, the velocity index n of silicon carbide was 3.24, 3.66, and 3.32, respectively, and the model constant k was 4.1959 × 10−11, 3.6436 × 10−11, and 4.1838 × 10−11, respectively. The velocity index n of YW3 was 2.29, 2.41, and 1.87, respectively, and the model constant k was 2.6176 × 10−7, 3.0017 × 10−7, and 3.1040 × 10−7, respectively. When the test results were compared with the numerical simulation results, the maximum error for silicon carbide was 6.59%, 7.71%, and 9.25%, respectively, and the maximum error for YW3 was 8.78%, 9.51%, and 5.97%, respectively. Finally, the erosion model of silicon carbide ceramics and YW3 was established via a large number of experiments and numerical simulations. When the target material and abrasive material are the same, it can be directly used for erosion prediction and structure optimization of natural gas equipment. Meanwhile, this paper provides a new idea for the establishment of gas–solid two-phase erosion model, and when the abrasive material and target material change, a new erosion model can be established according to the idea of this paper.

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.

Warm Pressing of Organosilicon Polymer Toward Monolithic Ceramics

Warm pressing of organosilicon polymers is often challenging due to the formation of cracks due to release of volatile compounds during the warm pressing process. The focus of the present study is to warm press crosslinked SMP‐10 powders into crack‐free compacts and to pyrolyze them to get bulk SiC monoliths. Crack formation during warm pressing is addressed by optimizing the crosslinking temperature, and the loss of formability of the powders crosslinked at higher temperatures is overcome with the use of uncured polymer as a binder. The crosslinking temperature of the preceramic polymer plays a crucial role in developing crack‐free green bodies. The amount of binder used is varied to study its effect on the bulk density of the pyrolyzed product. The warm pressed green bodies pyrolyzed at 1400 °C result in the formation of bulk silicon carbide ceramics and are characterized using X‐ray diffractometer and FTIR spectroscopy. Warm pressing is performed at a lower temperature than reported in the literature, and this limits the incorporation of oxygen during the warm pressing.

Silicon carbide ceramics formed by binder jetting: A study focusing on the printing layer thickness and the PIP densification process

Binder jetting (BJ) additive manufacturing has the advantages of high precision, fast forming speed, and no need for supporting structure, which is especially suitable for the forming of metallic and ceramic components with complex structures. In this paper, SiC ceramic parts were obtained by BJ additive manufacturing and precursor impregnation pyrolysis (PIP) cycles. It has been observed that the thickness of the printing layer significantly affects the strength of the SiC green body. The SiC green body exhibited the highest bending strength (3.1 ± 0.2 MPa) and lower dimensional deviation (0.47–1.64 %) when printed with a layer thickness of 50 μm. However, the bending strength of the SiC ceramics (after densification) had little variations when different printing layer thicknesses were utilized. In the subsequent densification process, the density, hardness, and bending strength of SiC ceramics increase as the number of PIP cycles increases obviously, and the flexural strength reached 228.7 ± 14.2 MPa after 9 PIP cycles, while the shrinkage rates in the X, Y, and Z direction were 1.9 %, 2.8 %, and 1.2 %, respectively. In addition, the influence mechanism of printing parameters on the strengths of the green bodies and SiC ceramics was also discussed. Specifically, it was found that with the layer thickness increase, the strengths of SiC ceramics also increase.

Development of conductive SiC-ZrN-TiB2 ceramics: A pathway towards electrical discharge machinable SiC based ceramics

Dense silicon carbide (SiC) composites with 0–30 vol% (ZrN-TiB2) were fabricated by using liquid phase spark plasma sintering at a relatively lower sintering temperature (1800 °C) and shorter holding time (5 min). The effects of co-addition of ZrN and TiB2 on densification, mechanical properties, and electrical conductivity of SiC ceramics were investigated. The reinforcement significantly enhanced density of sintered composites, while the phase analysis and microstructure confirm the suppression of β→α phase transformation in the SiC matrix. The fracture toughness ranged from 4.1 to 4.6 MPa·m0.5, hardness from 19.5 to 20.3 GPa, and electrical conductivity from 4.85 ×101 to 1.25 ×103 (Ω·cm)−1. Incorporating conductive reinforcements and nitrogen additives enhanced electrical conductivity. Successful wire-EDM cutting of SiC-ZrN-TiB2 composites demonstrate the feasible alternative to conventional machining of non-oxide ceramics with a maximum material removal rate of 8.54 mm2/min.

Bimodal powder optimization in SiC binder jetting for mechanical performance

Binder jetting (BJ) additive manufacturing has emerged as a promising technique for batch production of complex silicon carbide (SiC) ceramic components. However, the utilization of coarse powder in BJ often leads to lower density and strength in green parts and final composites compared to conventional fabrication methods. This study aims to enhance the mechanical performance of SiC ceramics through a novel bimodal SiC powder formulation for BJ, complemented by phenolic resin impregnation and pyrolysis (PRIP) and liquid silicon infiltration (LSI). The optimal ratio of bimodal powder, comprising 75 % coarse and 25 % fine powder, was determined through a comprehensive analysis of the microstructure and properties at various stages of the preparation process. The bimodal powder achieves a packing density of 48.3 % and exhibits satisfactory flowability. Notably, the density of the green part reaches 1.78 g/cm3, which is 31 % and 4.7 % higher than that of unimodal fine and coarse powders, respectively. Following the LSI process, the final Si-SiC composites display a high flexural strength of 276.6 ± 13.3 MPa and fracture toughness of 3.52 ± 0.12 MPa·m1/2. These values represent increases of 42.4 % and 25.3 %, respectively, compared to the composites derived from unimodal coarse powder. The material compositions and fabrication strategies proposed in this work offer an effective pathway for creating high-performance SiC ceramic composites via binder jetting.

Effect of the Carbon Component on the Strength of Reaction-Sintered Silicon–Carbide Ceramics

Effect of the Carbon Component on the Strength of Reaction-Sintered Silicon–Carbide Ceramics

Grinding Force Model and Experimental Study on Ultrasonic Assisted Spiral Grinding of Silicon Carbide Ceramic Materials

In order to reveal the mechanical properties of silicon carbide ceramic materials during the drilling process, based on the indentation fracture mechanics theory, a grinding force model of ultrasonic assisted spiral grinding for hole making was established, and the experimental results of ultrasonic assisted spiral grinding for hole making verified the mechanical model. The results showed that the experimental results had the same change trend as the predicted results of the established mechanical model, and the values were close to each other, indicating the accuracy of the established prediction model. The influence of different process parameters on the size accuracy of the hole inlet and outlet aperture after machining is analyzed. It is found that it should be selected as large rotation speed, moderate axial feed speed and small feed pitch to ensure the accuracy of the aperture and effectively suppress the aperture defects during ultrasonic assisted spiral grinding.

Heat Transfer of an Integrated Counterflow Ceramic Heat Exchanger

The ceramic-based heat exchanger is one of the leading contenders for high-efficiency concentrating solar power plants using a molten salt heat transfer fluid and a supercritical carbon dioxide Brayton power cycle operating at temperatures above 700 °C due to the excellent resistance of ceramics to corrosion, oxidation, erosion, creep, and fouling. In the present study, the thermal performance of a ceramic silicon carbide prototype heat exchanger, with semi-elliptical heat transfer channels, integrated header channels, and a counterflow configuration fabricated by using binder jetting additive manufacturing, was experimentally investigated. Experimental heat transfer tests of the prototype were conducted at high temperatures and under various test fluid flow rates and inlet temperatures. The experimental heat transfer rates compared favorably with simulation predictions.

Possibility of using boric acid and glutinous rice flour as additive for producing silicon carbide ceramic via pressureless solid-state sintering

This research aimed to investigate the possibility of using the mixture of boric acid and glutinous rice flour as a cost-efficient alternative additive for producing silicon carbide (SiC) ceramic sintered at 1800℃ via pressureless solid-state sintering. The results indicated that the addition of boric acid- glutinous rice flour mixture (10 wt%) in an appropriate ratio (0.5 by molar ratio) into the SiC mixture (90 wt%) enhanced the densification and flexural strength of sintered SiC samples. However, increasing boric acid/glutinous rice flour ratio reduces density and flexural strength. The 5.45 wt% carbon content was sufficient to remove the oxide layer of the SiC surface and improve the properties of SiC ceramic. In summary, the boric acid-glutinous rice flour mixture has a high potential to be used as an additive for producing dense and porous SiC ceramics via pressureless solid-state sintering.

Microstructure and Properties of Hot Pressing Sintered SiC/Y3Al5O12 Composite Ceramics for Dry Gas Seals.

Silicon carbide (SiC) ceramics with high bending strength were prepared by hot pressing sintering (HPS) with yttrium aluminum garnet (Y3Al5O12, YAG) as sintering additive, and the effects of YAG content and sintering temperature on the sintering behavior, microstructure and mechanical properties of SiC ceramics were investigated in detail. The uniform distribution of YAG to form a liquid phase and the driving force provided by hot pressing sintering decrease the sintering temperature, improve the densification of SiC ceramics, and refine the crystal size. By means of suitable sintering conditions with the additional amount of YAG of 5 wt%, the sintering temperature of 1950 °C and a pressure of 30 MPa, the resultant SiC/YAG composite ceramics possesses high sintering and mechanical properties with the relative density of 98.53%, the bending strength of 675 MPa, the Vickers hardness of up to 17.92 GPa, and the elastic modulus of 386 GPa. The as-prepared SiC/YAG composite ceramics are promisingly used as the dry gas seal materials in the centrifugal compressors.

Advancements in the research of high-temperature gas-cooled reactor fuel via additive manufacturing techniques

Recent advances in high-temperature gas-cooled reactor fuel research have captured the global spotlight, as modern operating contexts demand innovative responses to unprecedented challenges. This article offers an overview of contemporary directions in high-temperature gas-cooled reactor fuel design worldwide, pinpointing the shared operational demands and development patterns characteristic of these advanced fuels. It presents an innovative advanced fuel design, which incorporates multi-layer coated particles to boost safety and employs high-temperature-resistant silicon carbide (SiC) ceramics, seamlessly integrated with cutting-edge additive manufacturing (AM) techniques. This design heralds a shift toward modular fuel element solutions that are easily scalable, supporting the diverse array of advanced reactors and marking a significant step forward in the quest for high-temperature gas-cooled reactor fuel technologies.

High strength and high toughness Csf/SiC composites prepared by laser powder bed fusion/ reactive melt infiltration with the impregnation of boron-and silicone-containing phenolic resin

Laser powder bed fusion (LPBF) has emerged as an effective method for preparing complex structured silicon carbide (SiC) ceramics. However, the SiC components demonstrate low strength and high brittleness, which remain major challenges limiting its application. To overcome this limitation, short carbon fiber reinforced silicon carbide (Csf/SiC) composites are prepared by combining LPBF and phenolic resin binder impregnation (PRBI)-reactive melt infiltration (RMI), in which high char yield boron-and silicone-containing phenolic resin (BSiPF) impregnation is used to adjust the carbon density of green bodies and to reduce the pore size of green bodies. By optimizing the impregnation process, the carbon density can be brought close to the theoretical optimal value of 0.84 g/cm3, and the reduction of the pore size is conducive to the improvement of the reaction rate at the early stage of the reaction, which enhance the SiC phase content of Csf/SiC composites obtained by RMI. Meanwhile, the application of BSiPF results in a protective pyrolytic carbon (PyC) coating on the surface of Csf, which can reduce the erosion of Csf by molten Si during the RMI process, thus improving the fracture toughness of Csf/SiC composites. The final Csf/SiC composites exhibit the enhanced bulk density, bending strength and fracture toughness, reaching 2.90 ± 0.01 g/cm3, 257 ± 20 MPa, 3.52 ± 0.15 MPa m1/2, respectively. This study provides a new strategy for effective impregnation technique for the additive manufacturing (AM) of high strength and high toughness SiC composites.

Silicon carbide whiskers reinforced silicon carbide ceramics prepared by vat photopolymerization and liquid silicon infiltration

The development of additive manufacturing technique provides possibility to prepare SiC ceramics with complex shapes. However, defect control in the debinding and sintering stages is still a great challenge for the vat photopolymerized components. Here, SiC ceramics were manufactured by vat photopolymerization followed by liquid silicon infiltration, using SiC whiskers as the reinforcement. In the debinding stage, the SiC whiskers prevented the propagation of micro-cracks that induced by the formation and emission of gaseous substance. Also, the SiC whiskers provided channels for the infiltration of liquid silicon during sintering, thus the bulk density of the as-sintered SiCw/RBSC composite reached 2.95 g/cm3 at the whiskers fraction of 8 wt%. Because of the various toughening mechanisms introduced by SiC whisker, the flexural strength and Vickers hardness of the composite increased up to 352.2 MPa and 17.54 GPa, respectively. Thus, this work provides a new strategy to control micro-defects in vat photopolymerized SiC ceramics.

Unlocking the strength: the predictions of silicon carbide fracture toughness revealed through data-driven approach

Silicon carbide ceramics are widely used within various applications, including mechanical, chemical, aerospace and military; where the fracture toughness plays a crucial role. From the processing perspectives, the fracture toughness is controlled by the combination of starting phases and sintering conditions (including additives, atmosphere, temperature and pressure). However, the interplay of these factors makes the forward predictions of fracture toughness untreatable neither through experimentation nor physical modeling; not mention to the reverse estimations of optimal processing parameters. In this work, a data-driven strategy was proposed that firstly to predict the fracture toughness from processing parameters; and then to explore certain parameters that have large impacts on the fracture toughness. From running four different machine learning (ML) algorithms on a well-established dataset of SiC sintering recipe, it was found that the eXtreme Gradient Boosting (XGBoost) model possess the best performance with accuracy up to 88%. Further, the feature importance scores revealed that the sintering temperature and the types of sintering additives show their significant influence on fracture toughness. It was found that the sintering temperature is the most critical factor affecting the obtained fracture toughness of SiC, where the optimum temperature range is of 1800 °C–2000 °C; and also, the sintering additives of Al and Al2O3 have great influences on the obtained fracture toughness, where the optimum range of their mass fraction within the whole additives is 3–8 wt%. Finally, the developed model shows its capability to propose sintering strategy for the preparation of SiC ceramics with target fracture toughness.

Investigation on Enhanced Machinability of SiC Ceramics through Photocatalytic Vibration Composite Polishing.

The problems of low polishing efficiency and serious surface damage in the processing of silicon carbide (SiC) ceramics are well-known. In view of the above problems, a new method of photocatalytic vibration composite polishing (PVCP) combined with a compound control strategy was proposed. A vibration-assisted device was developed, and a compound control system was designed for the device to improve the trajectory tracking accuracy. Experiments were carried out to verify the effectiveness of the vibration-assisted device and the compound control system. In addition, methyl orange degradation and fading experiments, redox potential measurement experiments, and SiC ceramic surface hardness characterization experiments were carried out to reveal the effects of vibration and photocatalytic parameters on polishing solution oxidation and SiC ceramic surface mechanical properties. Finally, the effects of photocatalysis, vibration frequency, amplitude, and the compound control system on the polishing effect were analyzed. The results show that when the UV intensity is 100%, the polishing force is 3-4N, the vibration frequency is 400 Hz, the amplitude is 15 μm, and the surface roughness of SiC ceramics is reduced by about 11 nm after the introduction of the compound control system, which verifies the effectiveness of the combination of the compound control system and PVCP.

Fabrication of Layered SiC/C/Si/MeSi2/Me Ceramic-Metal Composites via Liquid Silicon Infiltration of Metal-Carbon Matrices.

The growing demand for composite materials capable of enduring prolonged loads in high-temperature and aggressive environments presents pressing challenges for materials scientists. Ceramic materials composed of silicon carbide largely possess high mechanical strength at a relatively low density, even at elevated temperatures. However, they are inherently brittle in nature, leading to concerns about their ability to fracture. The primary objective of this study was to develop a novel technique for fabricating layered composite materials by incorporating SiC-based ceramics, refractory metals, and their silicides as integral constituents. These layered composites were produced through the liquid-phase siliconization method applied to metal-carbon blanks. Analysis of the microstructure of the resultant materials revealed that when a metal element interacts with molten silicon, it leads to the formation of a layer of metal silicide on the metal's surface. Furthermore, three-point bending tests exhibited an enhancement in the bending strength of the layered composite in comparison to the base silicon carbide ceramics. Additionally, the samples demonstrated a quasi-plastic nature during the process of destruction.

Reliability comparisons between additively manufactured and conventional SiC–Si ceramic composites

AbstractAn additively manufactured reaction‐bonded silicon carbide ceramic composite is fabricated using a bimodal powder feedstock and the binder‐jetting printing technique. On fabricating, the ceramic is investigated to report its composition, mechanical, and thermal properties at room temperature and high temperatures (up to 750). The ceramic has a density of 2.76 g/cc, and shows a hardness of 21.74 GPa, and a flexure strength of 207.5 MPa at room temperature. The mechanical property of flexure strength is used to estimate its failure probability under applied stress, using a Weibull distribution. The mechanical properties and failure probabilities are compared with those of conventionally fabricated reaction‐bonded silicon carbide ceramics reported in the literature. These ceramics were fabricated using methods such as slip‐casting, compacting, and tape‐casting. The comparison is used to elucidate the advantages and areas of improvement of the present additive manufacturing technique for reaction‐bonded ceramics.

Modeling of Ultrasonic Vibration Trajectory and Grinding Force of Silicon Carbide Ceramics

Modeling of Ultrasonic Vibration Trajectory and Grinding Force of Silicon Carbide Ceramics

Development Strategy of Continuous Silicon-Carbide-Fiber-Reinforced Silicon Carbide Ceramic Matrix Composites in the Field of Advanced Nuclear Energy

Development Strategy of Continuous Silicon-Carbide-Fiber-Reinforced Silicon Carbide Ceramic Matrix Composites in the Field of Advanced Nuclear Energy