CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Yanzi Tang,Jincui Ren,Weixiang Yang,Yunuo Yang
TaC whiskers were prepared using the molten salt method with Ta 2 O 5 , activated carbon, NaCl/NaF, and nano Ni powders as raw materials. The study examined the effects of the ratios of these raw materials, reaction temperature, and reaction time on the phase composition and microstructure of the TaC whiskers, as well as their growth mechanisms. The results indicated that production and length-diameter ratio of the TaC whiskers initially increased with higher carbon content until a certain point, after which they began to decrease. The prepared TaC whiskers using NaCl as molten salt were acicular and had a low length-diameter ratio. The TaC whiskers prepared by NaF were quadrangular prism-shaped and had a high ratio of length to diameter. Insufficient molten salt resulted in poor diffusion and uneven distribution of the reactants, while an excessive amount led to increased whisker diameters and agglomeration of the TaC whiskers. When the content of Ni was low, there were not enough nucleation points for whisker growth, resulting in only a small quantity of TaC whiskers. Conversely, a high Ni concentration caused a decrease in the length-to-diameter ratio of the whiskers. As reaction temperature rose, both the production and length-diameter ratio of the TaC whiskers first rose and then fell. Prolonging reaction time could increase production and length-diameter ratio of the TaC whiskers. When the molar ratio of Ta:C:F:Ni was 1:4:1:25:0.10, with a reaction temperature of 1300 °C and a reaction time of 2 h, the TaC whiskers exhibited the highest production, purity and length-to-diameter ratio. These whiskers had with an average diameter of 0.8 μm and lengths spanning several microns. The TaC whiskers had a single crystal structure, with their growth direction aligned along the [001] crystal direction. The growth mechanisms of the TaC whiskers were controlled by both the vapor-liquid-solid and solid-liquid-solid mechanisms.
研究领域:
材料科学
·
晶体生长
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
·
2015
·
IF 1.97
Shu-Ting Liu,Kang-kang Yan,Yuan hu Zhang,Shi-di Jin,Ying Ye,Xue-Gang Chen
The increase in electromagnetic pollution due to the extensive exploitation of electromagnetic (EM) waves in modern technology creates correspondingly urgent need for developing effective EM wave absorbers. In this study, we carried out the magnesiothermic reduced the rice husk ash under different temperatures (400–800 °C) and investigated the electromagnetic wave adsorption of the products. The EM absorbing for all samples are mainly depend on the dielectric loss , which is ascribed to the carbon and silicon carbide content. RA samples (raw rice husk ashed in air and was magesiothermic reduced in different temperatures) exhibit poor dielectric properties , whereas RN samples (raw rice husk ashed in nitrogen and was magesiothermic reduced in different temperatures) with higher content of carbon and silicon carbide display considerable higher dielectric loss values and broader bandwidth for RL<−5 dB and −10 dB. For RN samples, the maximum bandwidth for −5 dB and −10 dB decrease with carbon contents, while the optimum thickness decrease with increasing SiC content. The optimum thickness of RN400–800 for EM absorption is 1.5–2.0 mm, with maximum RL of between −28.9 and −68.4 dB, bandwidth of 6.7–13 GHz for RL<−5 dB and 3.2–6.2 GHz for RL<−10 dB. The magnesiothermic reduction will enhance the potential application of rice husk ash in EM wave absorption and the samples benefited from low bulk density and low thickness. With the advantages of light-weight, high EM wave absorption, low cost, RN400–800 could be promising candidates for light-weight EM wave absorption materials over many conventional EM wave absorbers.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Siwen Cui,Yufei Ge,Shuailing Ma,Xiaoqi Zhang,Min Lian,Xinmiao Wei,Wei Li,Cun You,Qiang Tao,Tian Cui,Pinwen Zhu
Electrically conductive silicon nitride ceramics with both high hardness and electrically conductive properties are promising advancing ceramics. However, ensuring the high hardness while simultaneously enhancing their electrical conductivity poses a great challenge. In this work, Si 3 N 4 -carbon composites with different carbon content were synthesized with diamond phase transformation method under high pressure and high temperature (HPHT). The α→β phase transition in silicon nitride enables the coexistence of α/β phases, offering a hardness of up to 23.15 ± 0.08 GPa, comparable to dense silicon nitride ceramics and significantly higher than synthesized silicon nitride-graphite composites. Diamond uniformly distributed in the silicon nitride matrix is graphitized at high temperatures to form conductive channels, reducing resistivity to 2 × 10 - ⁴ Ω∙m, over a dozen orders of magnitude lower than pristine silicon nitride. This phase transition sinter mechanism provides a method for designing conductive Si₃N₄-based ceramics with high hardness.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Jinzhao Liu,Xinyu Chen,Hu Wang,Yun Chen,Liuliu Zhong,Chundong Zhang,Lei Wang,Hui Wan,Guofeng Guan
ZIF-67 derived cobalt-based catalysts have potential for Fischer–Tropsch synthesis (FTS). In this work, core–shell structured Co-Z@TiO2 catalysts with different graphitization degrees and carbon contents were handily prepared by adjusting the calcination process, using the ZIF-67 encapsulated by amorphous TiO2 as the precursor. By the protection effect of the residual carbon, the aggregation of cobalt species was suppressed. The dispersion and reducibility of the catalyst can be regulated by manipulating the type and amount of residual carbon. The Co-Z@TiO2 catalyst with proper carbon content exhibited high CO conversion (36.9%), C5+ selectivity (80.4%), and especially gasoline range hydrocarbons (49.3%). The catalyst also showed good stability during a 110 h reaction.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Xiao Sun,Chuanbing Cheng,Jianxing Shen,Yang Liu,Tailin Wang,Qian Ma,Runhua Fan
In this work, amorphous carbon/alumina (C/Al 2 O 3 ) metacomposites with tunable negative permittivity were synthesized by a facile impregnation method. We analyzed the influence of carbon content and the carbonization temperature on the microstructure and electrical properties of the metacomposites. It was found that the conductive carbon networks were formed in the composites with the higher carbon contents and carbonization temperatures, which lead to the appearance of a metal-like conduction and negative permittivity behavior. Low-frequency plasmonic state provided by plenty of free electrons in the carbon networks resulted in the negative permittivity, and its numerical values could be effectively adjusted by controlling the carbon content and carbonization temperature, which could be well explained by Drude model. This work provides a feasible way to prepare metacomposites with tunable negative permittivity, which will expand their potential applications in shielding, absorbing and novel capacitor fields.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2025
·
IF 3.8
Yiran Liu,Yimin Ouyang,Linwei Guo,Saidi Wang,Yihui Yang,Bin Du,Tao Zhang
Polymer-derived SiOC ceramics have demonstrated significant potential across various applications, including structure materials, energy, extreme thermal environments, and semiconductors. It is well-established that the carbon phase in SiOC plays a crucial role in determining the material's properties. However, the relationship between carbon phases and the mechanical properties of SiOC ceramics remains inadequately explored. In this study, a series of SiOC nanosphere powders with varying carbon content were successfully fabricated, and bulk samples were obtained using the spark plasma sintering (SPS) technique. The results demonstrate that both carbon content and sintering temperature play a synergistic role in determining the phase composition—such as the formation of SiC through carbothermal reduction—and the microstructural features, including densification and the distribution of free carbon in SiOC ceramics. These structural modifications significantly enhance the mechanical properties through multiple mechanisms. Among all the samples, the SiOC-C ceramics fabricated at 1600°C possess optimized mechanical properties, with a flexural strength of 38.48 MPa. These findings elucidate the potential mechanism for improving the mechanical properties of SiOC ceramics by introducing the carbon phase, which holds significant implications for the development of high-performance ceramic materials.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
CARBON
·
2022
·
IF 11.307
Bin Du,Yiran Liu,Yuan Chen,Junjie Qian,Tao Zhang,Anze Shui
Polymer-derived-ceramics (PDCs) are considered as a promising candidate for excellent microwave absorption under harsh environments due to their controllable microstructure at the molecular level. Herein, a series of silicon oxycarbide (SiOC) nanospheres are successfully fabricated through a PDC method and then pyrolyzed under argon atmosphere at different temperatures and the evolutions of microstructure and their microwave absorption properties are investigated simultaneously. It is found that the microwave absorption properties mainly depend on carbon content. With a relative carbon content of 38.13%, the carbon-rich SiOC nanospheres-1 pyrolyzed at 1400 °C possess excellent microwave absorption properties with a minimum reflection loss (RL) value of −56.28 dB at 6.8 GHz with a thickness of 2.93 mm. Electromagnetic analysis demonstrates that proper impedance matching, intrinsic attenuation ability, and the multiple reflection are responsible for the excellent RL. This work will provide a novel approach to obtain the PDCs with excellent microwave absorption properties.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2023
·Vol. 34
·期 18
·1-15
·
IF 2.8
Shi Haofan,Li Jinping,Zhang Gaoming,Meng Songhe
SiCN ceramic is a candidate material for high-temperature sensors because of its stability and semiconductor characteristics at high temperatures. The free carbon content within the SiCN ceramics is a main factor that affects its conductivity. This study adjusted the free carbon content inside amorphous SiCN by adding divinylbenzene into the precursor. The electrical properties of SiCN ceramics with different free carbon contents were explored using ultraviolet fluorescence spectrum and temperature-resistant experiments. The results showed that with the increase of divinylbenzene from 0 to 20%, the conductivity of SiCN ceramics at room temperature increases from 2.77 × 10 −9 to 3.66 × 10 −4 S/cm, and the forbidden bandwidth decreases from 3.81 to 2.25 eV. At the same time, the increase of divinylbenzene content would promote the hybridization extent of free carbon from sp 3 to sp 2 and improve the degree of order. This work could pave the way for applying amorphous SiCN serving as temperature sensors.
研究领域:
材料科学
·
半导体材料
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2022
·
IF 6.267
Shushi Zhang,Zhenyang Wang,Peng Hu,Jiating Rao,Jianliang Zhang,Jing Pang
The HIsmelt process is well suited for smelting vanadium-titanium magnetite and has significant potential. In this paper, the vanadium and titanium distribution behavior at 1450 °C in the basicity range of 0.3–1.2 during HIsmelt smelting vanadium titano-magnetite was investigated experimentally for the first time. According to thermodynamic calculations combined with experimental validation, lower C content increases the activity coefficients of vanadium and titanium in the metal. Higher basicity decreases the activity coefficients of TiO 2 and SiO 2 in the slag, improves the distribution ratio of vanadium and titanium. Increasing C content and reducing basicity could increase the content of vanadium in the metal and TiO 2 in the slag, which is favorable to vanadium extraction and titanium recovery. Furthermore, the V and Ti content in the hot metal increased significantly with rising smelting temperature. Higher smelting temperatures promote vanadium distribution into hot metal but not titanium distribution into slag. Finally, The Si and Ti distribution ratios have a positive connection according to the fitted models.
研究领域:
冶金学
·
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
MATERIALS RESEARCH INNOVATIONS
·
2024
·
IF 0
Hongdan Hu,Yaowen Wang
The experiment carried out halogen-free flame retardant modification treatment on polyethylene-based wood-plastic composite materials. The results showed that after adding flame retardant, the ignition time of the material increased to 76 seconds, an increase of 22 seconds. At combustion temperatures above 530°C, only a small amount of the material’s residue continues to evaporate. When the temperature rises to 800°C, the difference in the residual carbon content of the samples gradually becomes larger. The residual carbon content of sample 1# is only 10.1%. At this time, the residual carbon content of samples 7#, 8# and 9# are respectively Reaching 27.12%, 27.09% and 25.60%. The above results show that the thermal stability of composite materials has been greatly improved after adding nano-flame retardants, providing new ideas and methods for the application of flame retardant and halogen-free flame retardant materials of wood-plastic composites.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
Materials Today Communications
·
2021
·
IF 3.383
Shijiao Zhao,Rui Xu,Jingtao Ma,Changsheng Deng,Xing Cheng,Xingyu Zhao,Shaochang Hao,Jianjun Li
Zirconium nitride is an increasingly attractive material, owning to its wide range of applications. Nitridation with carbon as a reductant is a commonly used process for the preparation of transition metal nitrides. In this study, the nitridation of carbon-containing zirconia gels was studied as a method to synthesize zirconium nitride. The behavior of the gel upon heat treatment was investigated online. The evolution of the microstructure during nitridation was investigated using high-resolution transmission electron microscopy (HRTEM). The relationships between the gaseous species, crystalline phases, microstructure, and chemical elements of the resulting materials were established. The results showed that NH 3 , CH 2 O, CO 2 , CO, H 2 O, and HCN were the gaseous products in the nitridation process. Nucleation of the nanograins started with zirconium oxynitride . Transformation from oxynitride to nitride led to the occurrence of open-mouth-like defects on the particles. The enrichment of N atoms was accompanied by a core-shell structure. Finally, a systematic nitridation mechanism involving five stages was proposed. This study is important for understanding the nitridation process and controlling the structure and properties of transition metal nitrides.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Materials
·
2022
·Vol. 15
·期 17
·6028
·
IF 3.748
Wenhao Sha,Yingying Liu,Yabin Zhou,Yihua Huang,Zhengren Huang
In this study, different reaction-bonded boron carbide (RBBC) composites with a free carbon addition from 0 to 15 wt% were prepared, and the effect of the carbon content on the mechanical properties was discussed. With the free carbon addition increase from 0 to 15 wt%, the residual silicon content in the RBBC composite decreased first and then increased. Meanwhile, the strength of the RBBC composite improved first and then worsened. In the RBBC composite without free carbon, the B4C grains are obviously dissolved, the grains become facet-shape, and the grain boundary becomes straight. The microstructure of the composite was tested by SEM, and the phase composition of the composite was tested by XRD. The RBBC composite with the addition of 10 wt% free carbon has the highest flexural strength (444 MPa) and elastic modulus (329 GPa). In the composite with a 10 wt% carbon addition, the phase distribution is uniform and the structure is compact.
研究领域:
材料科学
·
机械工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）