CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Fu-Chen Liu,Bo-Wen Chen,De-Wei Ni,Fei-Yan Cai,Xue-Gang Zou,Chun-Jing Liao,Hong-Da Wang,Yu-Sheng Ding,Shao-Ming Dong
Long-term ablation behavior of Al 4 SiC 4 -YB 4 modified C f /ZrB 2 -SiC composites was characterized by air plasma torch at 2600 °C for 300 s. The phase composition and the microstructure evolution of the composites were investigated. The addition of YB 4 promotes the formation of nano t- Zr 0.92 Y 0.08 O 1.96 crystals, decreasing the phase transition stress in the oxide layer and reducing the volatilization of the glassy phase . However, the addition of Al 4 SiC 4 reduces the melting point of Zr-based oxides and the viscosity of the oxide layer. Therefore, the air plasma torch blows the oxide layer away, leading to the increase of linear recession rate.
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高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Shang Gao,Boyu Hu,Xin Song,Zhigang Dong,Renke Kang
Chemical mechanical polishing (CMP) offers promising pathway to smooth 4H-SiC. Dispersion stability of polishing slurry is crucial factor affecting 4H-SiC performance. Particles in polishing slurry can easily agglomerate due to poor dispersion stability, affecting surface quality of wafers. Nano-Al 2 O 3 is common particle in the slurry that directly controls mechanical removal. In this paper, the impact of different dispersants (PEG, (NaPO 3 ) 6 , and NH 4 PAA) on the dispersibility of slurry containing nano-Al 2 O 3 is studied. Results indicate that the slurry containing NH 4 PAA exhibits the greatest dispersion stability with superior 4H-SiC surface quality, with surface roughness (Sa) reaching 1.054 nm. The slurry containing PEG shows poor dispersion, leading to poor SiC surface quality, and the Sa reached 5.314 nm. The dispersion mechanism of different dispersants is also discussed.
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高影响因子
Journal of Natural Gas Chemistry
·
2011
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IF 1.345
Huiling Li,Yonggen Lei,Ying Huang,Yueping Fang,Yuehua Xu,Li Zhu,Xin Li
The Cu 2 O/SiC photocatalyst was obtained from SiC nanoparticles (NPs) modified by Cu 2 O. Their photocatalytic activities for reducing CO 2 to CH 3 OH under visible light irradiation have been investigated. The results indicated that besides a small quantity of 6H-SiC, SiC NPs mainly consisted of 3C-SiC. The band gaps of SiC and Cu 2 O were estimated to be about 1.95 and 2.23 eV from UV-Vis spectra, respectively. The Cu 2 O modification can enhance the photocatalytic performance of SiC NPs, and the largest yields of methanol on SiC, Cu 2 O and Cu 2 O/SiC photocatalysts under visible light irradiation were 153, 104 and 191 μmol/g, respectively.
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高影响因子
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
·
2024
·
IF 1.6
Xiangzhou Miao,Baijun Yan
In this study, thermodynamic calculations indicate that using silicon carbide (SiC) as an additive for the reductive decomposition of industrial by-product (IBP) gypsum is a feasible method to lower decomposition temperature and avoid the generation of liquid phase. Experimental results show that the decomposition rate of IBP gypsum exceeded 90% at 950°C for 2 h, while avoiding the generation of liquid phase. In addition, it was found that an intermediate product, 2Ca 2 SiO 4 ·CaSO 4 , was generated during the decomposition process. Through the reaction mechanism and kinetics analysis of IBP gypsum and SiC, the decomposition process can be divided into two steps. The first step was the conversion of CaSO 4 to 2Ca 2 SiO 4 ·CaSO 4 (decomposition rate <60%), and the chemical reaction was the controlling step. The second stage was the conversion of 2Ca 2 SiO 4 ·CaSO 4 to Ca 2 SiO 4 (decomposition rate >60%), and three-dimensional diffusion was the controlling step. This novel method not only successfully lowered the decomposition temperature of IBP gypsum, but also avoided liquid phase generation.
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高影响因子
LANGMUIR
·
2024
·
IF 3.7
Tongguo Huo,Kai Cao,Jianxin Zheng,Dan Zhu,Yuan Lin,Yu Dai,Jian Wu
The mechanism of β-SiC preparation via chemical vapor deposition (CVD) of the SiCl4–CH4–H2–N2 system remains unclear. Consequently, the change of molar Gibbs free energy of the CVD β-SiC chemical reaction in the SiCl4–CH4–H2–N2 system has been studied by the Helsinki Software Corporation (HSC) Chemistry code for the first time. The role of nitrogen in the reaction was confirmed. Seven potential reaction pathways of CVD β-SiC were presented, and the thermodynamic equilibrium components of each reaction were calculated systematically. The most viable reaction pathway and corresponding optimal temperature range for CVD β-SiC were determined. In addition, a kinetic study of CVD β-SiC was conducted. The microscopic morphology and crystal structure of β-SiC coatings prepared on the graphite surface at different temperatures were charactered by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman, etc. Ultimately, through SEM, XRD, and Raman observation, uniform and dense β-SiC coatings with fine grains and high crystallinity were successfully obtained. Furthermore, large β-SiC-coated graphite trays with diameters of 230 and 465 mm were prepared by CVD using the SiCl4–CH4–H2–N2 system, and the average thickness of β-SiC was about 100.6 μm. This study provides a theoretical basis and technical recommendations for the fabrication of SiC-coated graphite trays used in metal–organic chemical vapor deposition (MOCVD) equipment.
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PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·
IF 2.7
Bozhen Wu,Yujing Yu,Peng Wu,Yidong Wu,Jiang Huang,Xuejiao Song
The design and preparation of lightweight and flexible electromagnetic interference (EMI) shielding composites with high efficiency and low reflection are critical to the electronic field. First, silver nanowires (AgNWs) were vacuum filtered on the electrospun thermoplastic polyurethane (TPU) fibrous film. Then, by combining the adhesive with the electrospun silicon carbide nanowhisker (SiCnw) @TPU composite fibrous film, the asymmetric EMI shielding composite films with high electromagnetic shielding efficiency (EMI SE) and low incident power were obtained. The lower AgNWs-TPU layer provides the primary EMI SE, and the upper SiCnw@TPU fibrous film is used for electromagnetic wave absorption. This unique asymmetric structure, the synergistic effect of SiCnw's particular absorbing function and the excellent conductivity of the AgNWs layer make the film show high overall SE (SE T = 55.18 dB). In order to improve the absorption effect of the composite film, the number of layers of SiCnw@TPU was adjusted, resulting in a final reflection coefficient value as low as 0.55. This work proposes a new strategy for developing EMI shielding composite films with high efficiency and low reflection, serving as a reference.
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高影响因子
ACS Applied Electronic Materials
·
2024
·
IF 4.3
Lujia Han,Huakang Zhang,Xiao Yang,Zengchao Yang,Yong Li,Jiangtao Li,Jinhong Yu
SiC nanowires (SiCNWs) are promising fillers due to their high thermal conductivity, chemical stability, and mechanical strength. Currently, the reported methods are generally complicated in operation and low in yield, which makes it difficult to realize industrialized produce. In this study, large quantities of SiCNWs with high aspect ratio and crystallinity were successfully synthesized using a fast and reliable combustion synthesis (CS) method. On this basis, the superflexible poly(vinyl alcohol) (PVA)/SiCNWs composite films with horizontally aligned SiCNWs structure were prepared via the electrospinning. At a fraction of 10 wt %, the thermal conductivity of the composite films was remarkably improved, up to 19.18 W/(m K). PVA/SiCNWs composites with good thermal stability and excellent tensile strength can effectively diffuse the heat generated during the operation of LED devices, which has promising thermal management applications in foldable electronic devices.
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高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2024
·Vol. 108
·期 1
·e20141
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IF 3.5
Fang He,Yejie Cao,Yongsheng Liu,Jingxin Li,Jing Wang,Binghui Zhang,Ning Dong
SiC f /SiC composites have emerged as one of the most promising materials for aero-engine hot-end structures. However, their performance is limited by their susceptibility to oxidation and corrosion reactions with oxygen and water vapor. To overcome this challenge, antioxidant-modified phases are introduced into matrices of SiC f /SiC composites which improve their water and oxygen resistance. In this study, the resistance of SiC f /SiC composites modified by yttrium silicate matrix (SiC f /SiC-YS composites) to air at 1000–1400°C and water-oxygen environments at 1200°C was investigated. The diffusion paths of oxygen in SiC f /SiC-YS composites and the antioxidant behavior of the yttrium silicate matrix were discussed. Additionally, the differences in oxygen and water-oxygen corrosion resistance of SiC f /SiC-YS composites at the same temperature were compared. The strength retention of SiC f/ SiC-YS composites after oxidation and water-oxygen corrosion at 1200°C were 138.6% and 108.8%, respectively. This indicates that the addition of water vapor accelerated the degradation of SiC f /SiC-YS composites. By comparing with SiC f /SiC composites, it can be concluded that the modification of the yttrium silicate matrix considerably improved the oxidation resistance of SiC f /SiC composites.
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高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
P. Wang,S.S. Zhu,S.P. Zhang,F. Su,J.K. Yuan,Y.J. Jia,Y.Q. Fu,T. Li,Y.L. Zhang,P. Ramasamy,J. Eckert,C.S. Lao,Z.W. Chen
Zr-based ultra-high temperature ceramics (UHTCs) are widely used as the key parts of aircrafts in thermal protection systems. However, such materials usually have a high sintering temperature and it is difficult to obtain complex parts using traditional manufacturing methods. This study reports on the success preparation of complex Zr-based UHTCs by a light-curing 3D printing process. The results indicate that the smaller the precursor particle size, the higher is the viscosity of the slurry used for printing. Slurries with a better curing performance can be prepared by mixing various active diluents and photoinitiators with an optimized certain proportion. The stability of the slurry can be improved by adding coupling agents and dispersants. The main components of the 3D printed green parts are ZrC, SiC and pyrolytic carbon at 1800 °C, yielding a high compressive strength (102 ± 2 MPa) and elastic modulus (65 ± 1 GPa). ZrC/SiC composite ceramic parts with low open porosity (3.99 %) were obtained by 3D printing after heat treatment, which provides an effective way to design complex UHTC parts for extreme environment applications.
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高影响因子
MATERIALS CHARACTERIZATION
·
2024
·
IF 4.8
Yao Yang,Jianqiang Bi,Kangning Sun,Hongli Hou,Linjing Qiao,Guandong Liang,Shaoyin Wang,Shuyong Liang,Jilie Yuan,Yueguang Chen
The fracture toughness and oxidation resistance are crucial factors affecting the practical applications of high-entropy diboride ceramics (HEBs). In this study, silicon carbide whiskers (SiC w ) were introduced as a reinforcement for HEBs for the first time. To achieve a uniform dispersion of SiC w within the HEB powders, a combination of simultaneous ultrasonic dispersion, mechanical agitation, and freeze-drying technology was employed. Consequently, a series of composites, (Hf 0.2 Zr 0.2 Ta 0.2 V 0.2 Nb 0.2 )B 2 -nSiC w ( n = 0–20 vol%), were densified by spark plasma sintering. The effect of SiC w on the microstructure and mechanical properties of the HEBs were studied, as well as the toughening mechanism involved. The results revealed that the introduction of SiC w led to grain-size refinement in (Hf 0.2 Zr 0.2 Ta 0.2 V 0.2 Nb 0.2 )B 2 , along with significant improvements in relative density, hardness, fracture toughness, and oxidation resistance. The relative density, hardness and fracture-toughness of (Hf 0.2 Zr 0.2 Ta 0.2 V 0.2 Nb 0.2 )B 2 -SiC w composites exhibited an initial increase followed by a decrease with increasing SiC w content. Specifically, the (Hf 0.2 Zr 0.2 Ta 0.2 V 0.2 Nb 0.2 )B 2 –15 vol% SiC w composite simultaneously obtained the highest hardness of 25.6 GPa and fracture-toughness of 4.8 MPa·m 1/2 , representing a 26% improvement compared to (Hf 0.2 Zr 0.2 Ta 0.2 V 0.2 Nb 0.2 )B 2 ceramics.
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高影响因子
Materials Today Communications
·
2024
·
IF 3.7
Jie You,Yang Wang,Hongwei Wang,Jian Yang,Quan Li,Jian Gu
In this paper, a new process for preparing porous SiC foam with three-dimensional network structure is presented. A certain thickness of SiC coating is deposited on the surface of ultra-light carbon skeleton by CVD process, so as to achieve effective control of its structure and mechanical properties. The effects of CVD deposition time on the density, porosity and skeleton thickness rates of SiC foams were explored. By increasing the CVD deposition time, the structure of SiC foams can be effectively regulated, and the mechanical properties of SiC foams can be significantly improved. The porosity of the prepared SiC foam can be adjusted in a wide range (26.9%∼94.68%). When the density of SiC foam increases from 0.67 g/cm 3 to 2.36 g/cm 3 , its bending strength increases from 27.4 MPa to 136.9 MPa, which is significantly improved. After high temperature oxidation treatment (800–1200 °C), the mechanical properties of SiC foam will be further improved. However, when the oxidation temperature reaches 1400 °C, its mechanical properties will be reduced. This research provides a new idea for the preparation of high-performance porous SiC ceramics, and lays a foundation for its structural design, manufacture and application.
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高影响因子
JOURNAL OF POLYMER RESEARCH
·
2025
·Vol. 32
·期 7
·1-8
·
IF 2.8
Liu Huiping,Sui Luyu,Luo Shilei,Wang Zixin,Xu Meng,Zhong Ming,Hou Haoqing,Peng Xinwen
Polyimide (PI) is very popular in polymer film capacitors due to its excellent performance and easy film-forming properties. However, its relatively low dielectric constant (approximately 3–4) limits its application and development in the field of high-performance capacitors. In general, dielectric constant can be enhanced effectively by adding special filler materials into polyimide. In this study, core–shell structured C@SiC nanoparticles were synthesized via a hydrothermal method. Novel polyimide composites (C@SiC/PI) were obtained by dispersing C@SiC nanoparticles into polyamic acid, followed by thermal imidization. The dielectric constant of C@SiC/PI composite material is as high as 40.2, which is 11.4 times that of pure PI. The maximal discharging energy density reached up to 2.49 J cm −3 with 10% C@SiC nanoparticles, which is almost 3 times higher than pure PI under identical conditions. Additionally, the composites have excellent thermal stability with a decomposition temperature of 5% above 530℃. The tensile strength of the composite film is in the range of 89.7–130.50 MPa, and the elongation at break is between 5.4% and 9.1%, maintaining good mechanical properties. Consequently, the fabricated composites hold significant promise for applications in polymer thin-film capacitors and flexible electronics.
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高影响因子
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