JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Jia-Qi Zheng,Jian Chen,Ming Zhu,Wen-Hui Chen,Ning-Ning Ma,Xiu-Min Yao,Zheng-Ren Huang
N-doped SiC-MoSi 2 ceramics were successfully fabricated by hot pressing in N 2 using Y(NO 3 ) 3 .6 H 2 O as both sintering aids and additional N sources. The impact of Y(NO 3 ) 3 .6 H 2 O content on the densification, electrical properties, and infrared emission performance of the resulting ceramics were investigated. The distribution of Y-based sintering aid is improved by melting of Y(NO 3 ) 3 .6 H 2 O during slurry drying, enabling the relative density to increase up to 97.4%. Y(NO 3 ) 3 .6 H 2 O subsequently decomposes during sintering and allows the substitution of atomic N for the C sites in SiC lattice and production of the N-derived donor level. A larger amount of N dopant elevates the carrier density up to 1.90 × 10 16 cm -3 . Remarkably, The SiC − 10 wt% MoSi 2 ceramics sintered with 16.9 wt% Y(NO 3 ) 3 .6 H 2 O exhibits the lowest electrical resistivity (0.791 Ω·cm at room temperature) and highest infrared emissivity (0.913 at 800 ℃), the latter of which may also be attributed to lattice distortion induced by N doping . This work demonstrates N doping as a prospective strategy for synergistically optimizing the electrical conduction and infrared emission performance of SiC-based ceramics for infrared source applications.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2019
·
IF 3.192
Lu Zhu,Yousen Zhu,Xuanru Ren,Ping Zhang,Jianghao Qiao,Peizhong Feng
MoSi 2 -MoB-ZrO 2 composite powders are one-step synthesized prepared by self-propagating high-temperature synthesis (SHS), which are further utilized to prepare the oxidation protective coatings by spark plasma sintering (SPS) method on molybdenum substrate. Microstructure and properties of the coatings were investigated and determined. Oxidation behavior of the coatings at high temperature was also studied. The results showed that the composite coating is dense and crack-free due to the addition of ZrO 2 , which is beneficial for the decrease of mismatch in coefficient of thermal expansion, and no void exists in the diffusion layer owing to the diffusion of Si, which is inhibited by adding MoB. Compared with the pure MoSi2 coating, the high hardness of the composite coating is enhanced by about 20% while the fracture toughness of the composite coating is improved by about 25%, which makes the occurrence of intergranular fracture , crack deflection and crack bridging. After oxidation at 1400 °C for 80 h, MoSi 2 coating failed while xMoSi 2 -MoB-3ZrO 2 (x = 3, 4, 5) composite coating still kept its protective effect. Only a little substrate is consumed during oxidation and improved oxidation resistance is gained by MoSi 2 -MoB-ZrO 2 composite coating. 3MoSi 2 -MoB-3ZrO 2 coating shows the relatively best oxidation resistance due to the formation of crack-free oxide film on the surface of the coating.
研究领域:
材料科学
·
表面工程
·
高温氧化
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陶瓷涂层
·
粉末冶金
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Shiquan Zhang,Jian Zhang,Sheng Hu,Ruizhi Zhang,Junguo Li,Qiang Shen
Ablative thermal protection materials are widely used in entry and re-entry vehicles which benefit from their strong adaptability. However, long-term ablation has been a limitation due to the consumption of the matrix of the ablative materials. In this work, the microstructure evolution and ablation properties of the MoSi 2 /mica-modified CF/BPR composites with and without hollow silicate glass microspheres (HSMs) under protracted ablation have been investigated. The mass ablation rates decreased while the linear ablation rates increased when the ablation times were prolonged. The composites with 30 vol.% HSMs have good insulation properties, shown by a lower backside temperature of 240.9 °C after 100 s of ablation. The decrease in thermal conductivity limited heat transfer in both the axial and horizontal directions. This led to heat concentration and severe ablation at the central surface. The three-dimensional porous and the ladder structure formed in the transfer region, and the features gradually disappeared while extending the ablation times because of the flame erosion and formed liquid phases. The heat diffusion and concentration within the matrix established a gradient temperature field, which determined the ablation behavior and mechanism, providing valuable insights for the development of advanced ablative thermal protection materials.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2024
·
IF 6.3
Shiquan Zhang,Jian Zhang,Suohui Yang,Sheng Hu,Junguo Li,Qiang Shen
Improving the ablation and mechanical properties of ablative thermal protection composites by introducing modified fillers which simultaneously with an unavoidable increase in density. Balancing this increase in density while achieving lightweight properties is crucial for the development of effective ablative composites. In this paper, different contents of the hollow silicate glass microspheres (HSMs) are incorporated into MoSi 2 /mica-modified CF-BPR composites to investigate the impact of HSMs. The results show that HSMs play a positive role in reducing the density and thermal conductivity of the composite. The ablation and insulation properties of the 30 vol.% HSMs composites exhibit a mass ablation rate of 0.035 g/s and a linear ablation rate of 0.015 mm/s, alongside the lowest backside temperature. A significant improvement in flexural strength after static ablation at 1500 °C reached 82.59 MPa and maintained a relatively high level after 1600 °C. HSMs act as interlaminar skeletons, enhancing the shearing strength of the composite and facilitating the formation of a protective liquid phase around the carbon fibers to prevent oxidation. The increasing toughness of carbon fibers further enhances the mechanical strength of the composites.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2024
·
IF 11.3
Miao Liu,Ying He,Ying-Ying Jiao,Ling Ding,Di An,Yang Yang,Qing-Qing Hao,Hui-Yong Chen,Qun-Xing Luo
The nature of Mo-catalyzed glucose epimerization in the aqueous phase was elaborately studied. We herein formulate the thermodynamic properties (e.g., ΔrHT, ΔrGT, and Keq.T) of the reversible epimerization by collecting the equilibrium composition. The isotopic tracing and NMR spectra show that the overall tautomerization network encompasses the reversible epimerization and isomerization and the irreversible degradation of all hexoses. The leaching tests and kinetic and spectroscopic studies reveal that glucose epimerization catalyzed by Mo-containing solid catalysts in the aqueous phase resembles homogeneous catalysis. All catalysts enable a near-equilibrium yield of mannose (28%) at 373 K except MoP but undergo a different kinetic course of which MoN is the best catalyst according to the apparent kinetic parameters. The molybdenum species dissolved in an aqueous solution evolves into the truly active centers of the MoVI–O–MoVI bridged polymolybdates. Moreover, we propose that a single Mo center as Lewis acidic site coordinates with the aldoses to form a bidentate complex, which thereby contributes two different mechanisms to generate the epimers, viz., the intramolecular 1, 2-carbon exchange and two-step isomerization. The former proceeds through a three-membered cyclic transition state (TSC) that mediates the simultaneous cleavage of the bond between C-2 and C-3 and formation of the bond between C-1 and C-3, whereas the latter undergoes two hydride transition states (TSH-1 and TSH-2) via the hydride transfer twice, leading to the chiral inversion of the configuration at C-2. Last but not least, the presence of phosphates in an aqueous solution leads to the deactivation of Mo-based catalysts because of the interplay between glucose and phosphates.
研究领域:
催化化学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2026
·
IF 6.7
Feng Jiang,Chenchen Li,Xiang Ling
Molybdenum (Mo) is a promising structural material for ultra-high temperature applications, but its catastrophic oxidative degradation remains a critical bottleneck. Conventional single-layer silicide coatings often fail prematurely due to either weak interfacial adhesion (spallation) or insufficient long-term structural stability (cracking). To overcome these limitations, a novel dual-layer composite coating was developed in this study. An inner Mo-Si diffusion layer (∼90 μm) was first fabricated by pack cementation process to ensure robust metallurgical bonding with the Mo substrate. Subsequently, an anti-oxidative outer layer (∼98 μm) containing MoSi 2 , boron and quartz was deposited using slurry sintering technique. Isothermal oxidation tests revealed that the composite coating exhibited excellent protective performance at 1500 °C in air, with only minimal mass loss of 0.178 mg/cm 2 after 9 h. Microstructural analysis demonstrated that bidirectional Si diffusion dynamically transformed the coating into a highly stable gradient structure of SiO 2 -Mo 5 Si 3 -MoSi 2 -Mo 5 Si 3 during high-temperature exposure. The superior oxidation resistance was attributed to a synergistic anti-oxidation mechanism: the inner layer physically anchored the coating to prevent spallation, while the outer layer continuously generated a B 2 O 3 -fluxed fluid borosilicate glass phase that effectively sealed microcracks and pores. This work provides an effective architectural design strategy for developing high-performance oxidation-resistant coatings on refractory metals in ultra-high temperature environments.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2025
·Vol. 40
·期 5
·1231-1238
·
IF 1.1
Yang Suohui,Zhang Shiquan,Zhang Ruizhi,Zhang Jian,Shen Qiang
The surface of MoSi 2 -SiB 6 / phenolic resin matrix composites was modified by mica, and the thermal oxidation behavior of the composites and the mechanical properties of the pyrolysis products were studied. The results showed that the mica improved the thermal properties of the composites, the thermal expansion coefficient decreased, and the liquid phase formation caused the composites to shrink and increase the density. The flexural strength of mica surface modified composites not only increased to 78.64 MPa after thermal treatment at 800–1 200 °C, but reached 83.02 MPa after high temperature treatment at 1 400 °C. The improvement of the mechanical properties of the residual product benefits from the formation of high temperature ceramic phases such as Mo 2 C and MoB, and the improvement of the shear strength of the composites by the mica. The shear strength of MBm5-2 at room temperature reached 33.08 MPa, indicating that the improvement of the interlayer properties of the composites further improved its mechanical properties.
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Wang Luyan,Liu Rongjun,Wang Yanfei,Li Duan,Miao Huaming
The oxidation resistance of C/C composites in dynamic environments across a wide temperature range still needs improvement. Studies have shown that doping with Al can enhance the oxidation resistance of ultra-high-temperature ceramic coatings over a broad temperature range. However, there has been limited research on the oxidation behavior of Al-doped ultra-high-temperature ceramic coatings under dynamic conditions.In this study, HMSSB (HfB 2 , MoSi 2 , SiC, SiO 2 , B 2 O 3 ) coatings and Al-doped HMSSB (A-HMSSB) coatings were prepared on SiC-coated C/C composites. After oxidation at 1200°C and 1500°C for 4 h and 5 h, respectively, the SiC/HMSSB composite coating exhibited significant porosity, leading to severe oxidation of the C/C substrate. In contrast, the SiC/A-HMSSB coating formed a dense and well-sealed oxide glass layer, resulting in lower mass loss rates of 10.08% and 9.23% after oxidation.
研究领域:
材料科学
·
表面工程
·
陶瓷涂层
·
高温材料
·
复合材料
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2025
·
IF 14.2
Shengjian Mao,Ying Yu,Zhichao Xue,Yipeng Guo,Wenyan Huang,Siqi Lan,Jiaxue Zhang,Kaiqi Chen,Xinqi Chen,Rongqian Yao
Lightweight, heat-insulating fiber composites are highly sought after for aerospace applications, yet conventional manufacturing methods often depend on specialized feedstocks and complex spinning processes, limiting designability and multifunctionality. In this work, we present a molecular orthogonal self-assembly strategy for the energy-efficient and eco-friendly synthesis of COF&HOF fibric materials. Through biomimetic design inspired by swallow's nest architectures, we fabricated advanced fabric composites via conformal coating modifications. When integrated with ablative coatings, these fabrics demonstrate exceptional dynamic thermal management capability, exhibiting minimal backside temperature rise (ΔT < 82 °C) under butane flame exposure. Pyrolysis yields ultralight ceramics with remarkably low density (0.32 g/cm 3 ) and thermal conductivity (162.0 mW·m −1 ·K −1 ), while high-temperature annealing induces the formation of 15R–SiC single-crystalline fibers. Furthermore, incorporation of refractory compounds enables in situ conversion into high-entropy ceramic composites, featuring ultralow density (0.39 g/cm 3 ), superior thermal insulation (173.39 mW·m −1 ·K −1 ), and excellent electromagnetic wave absorption. Intriguingly, the ceramicization process triggers spontaneous hierarchical self-construction, generating nanostructures such as nanofibers, ribbons, spheres, and nanowires. This work establishes a sustainable paradigm for designing advanced artificial fabrics, high-entropy ceramics, and multifunctional composites with tailored properties for next-generation aerospace applications.
研究领域:
材料科学
·
纳米技术
·
陶瓷材料
·
复合材料
·
航空航天工程
·
热绝缘
·
电磁性能
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2015
·
IF 4.074
Zidan Zhou,Xinwen Peng,Linxin Zhong,Lan Wu,Xuefei Cao,Run Cang Sun
Electrospun cellulose acetate (CA) membrane was employed as a support that provided sites for AgCl crystals in situ growth. The Ag@AgCl crystals on electrospun CA composites with exposed {1 0 0} and {1 1 1} facets were fabricated at room temperature by a double diffusion technique. The crystal structure, morphology, composition, and absorption light ability of CA supported Ag@AgCl were characterized utilizing X-ray powder diffraction (XRD), scanning electron microscopy (SEM), attenuated total reflection-infrared intensity (ATR-IR), X-ray photoelectron spectroscopy measurements (XPS), energy dispersive spectrometer (EDS) and ultraviolet–visible (UV–vis) diffuse reflectance spectra, respectively. The photocatalytic activity of the catalysts was evaluated using methyl orange (MO) as a target. The CA supported cubic Ag@AgCl catalyst exhibited much higher catalytic activity than octahedral catalyst in terms of the degradation of MO under visible light. The 10 mg CA based cubes could completely degrade MO (10 mg L −1 ) in 160 min. The photocatalyst still exhibited a good catalytic ability after three times.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Ruizheng Xu,Guiyu Wei,Zhemin Xie,Sijie Diao,Jianfeng Wen,Tao Tang,Li Jiang,Ming Li,Guanghui Hu
Increasing the efficiency of charge transfer and separation efficiency of photogenerated carriers are still the main challenges in the field of semiconductor-based photocatalysts. Herein, we synthesized g-C 3 N 4 @V 2 C MXene photocatalyst by modifying g-C 3 N 4 using V 2 C MXene. The prepared photocatalyst exhibited outstanding photocatalytic performance under visible light. The degradation efficiency of methyl orange by g-C 3 N 4 @V 2 C MXene photocatalyst was as high as 94.5%, which is 1.56 times higher than that by g-C 3 N 4 . This was attributed to the V 2 C MXene inhibiting the rapid recombination of photogenerated carriers and facilitating rapid transfer of photogenerated electrons (e − ) from g-C 3 N 4 to MXene. Moreover, g-C 3 N 4 @V 2 C MXene photocatalyst showed good cycling stability. The photocatalytic performance was higher than 85% after three cycles. Experiments to capture free radicals revealed that superoxide radicals (·O 2 − ) are the main contributors to the photocatalytic activity. Thus, the proposed g-C 3 N 4 @V 2 C MXene photocatalyst is a promising visible-light catalyst.
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
危险品化学品经营许可证（带存储）