Surfaces and Interfaces
·
2024
·
IF 5.7
Wenhao Du,Fanhao Zeng,Yafang Gao,Ziwei Wang,Meiyan Chen,Zhi Li
Increasing the high-temperature anti-oxidation time of Carbon/carbon(C/C) composites faces significant challenges for conventional coatings. Herein, a unique bi-layer coating of HfC-TaC-B 4 C-SiC(HTBS)/ZrSiO 4 -glass(ZA) was proposed and prepared through slurry sintering method, and their oxidation behavior and mechanism were investigated. The results show that after oxidation at 1673 K in air for 750.5 h, the mass loss of the coated C/C was only 3.48% with about 720 h of weight gain oxidation, indicating that the anti-oxidation time has increased by two or three times compared to traditional coatings. The improved oxygen resistance performance was mainly attributed to the hinder layer of Si/Hf-Ta-Si-O during oxidation, which grew with the simultaneous carbothermal reduction reaction of SiO near matrix and oxidation reaction of HTBS. This is beneficial to lowering the thermal mismatch of coating system, reducing the connected thermal stress cracks as oxygen permeation channels. Our findings provide a new insight on improving the long-time thermal protection performance of C/C composites.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Qizhong Li,Zhangpeng Meng,Bing Xiao,Jiaojiao Li,Kai Liu,Meijun Yang,Song Zhang,Takashi Goto,Rong Tu
HfC-HfB 2 -SiC composites were prepared by arc melting using HfC , HfB 2 and SiC powder as raw materials. The ternary eutectic composition of 16HfC-17HfB 2 -67SiC (mol%) was first identified, showing a complicated maze microstructure of HfC, HfB 2 and SiC approximately 500 nm in thickness. The eutectic temperature of the HfC-HfB 2 -SiC composite was nearly 2760 K. The Vickers hardness and fracture toughness of the HfC-HfB 2 -SiC ternary eutectic composite were 20.8 GPa and 7.7 MPa m 1/2 , respectively. With increasing temperature from 300 to 800 K, the electrical conductivity decreased from 8.8 × 10 5 to 4.3 × 10 5 Sm −1 , whereas the thermal conductivity increased from 28 to 32 W m −1 K −1 .
研究领域:
材料科学
·
冶金学
·
复合材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Xinhao Shi,Liping Wang,Wanbo Hou,Jiahui Ding,Tao Feng,Hongjiao Lin,Mingde Tong
Multiphase HfC-SiC ceramic matrix composites were prepared by a combination process. The interface mechanics and ablation properties behaviors were investigated. Introducing the PyC-SiC interface, the composites showed a second-order pull-out mechanism. The mechanical failure model showed that fibers and matrix have different failure strain under load depending on the component that fails first. Moreover, the ablative airflow in the center area will spread to the edge area through the thermal shock microcracks generated. Increasing of the heat flux, the crack width gradually increased to be ditches. It accelerated the evolution of surface morphology, which showed HfC-SiC substrate was first transformed into Hf-Si-O solid solution on the process of phase transformation of oxidation products from 1680 ℃ to 2150 ℃, and eventually sintered into HfO 2 . The change in the morphology of oxidation product consumed more heat and protected the substrate from oxidation, resulting in improving the ablation resistance of composites.
研究领域:
材料科学
·
陶瓷基复合材料
·
机械工程
·
热防护系统
·
烧蚀研究
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2017
·
IF 3.454
Jincui Ren,Yulei Zhang,Pengfei Zhang,Tao Li,Jinhua Li,Yang Yang
To improve the ablation resistance of carbon/carbon composites in cyclic ablation environment, SiC/HfC ceramic coating reinforced by HfC nanowires was prepared. The microstructure, bonding strength , coefficient of thermal expansion and cyclic ablation resistance of the as-prepared coating were investigated. After incorporating HfC nanowires, the bonding strength between inner SiC coating and outer HfC coating was increased. HfC nanowires could relieve the coefficient of thermal expansion mismatch between inner and outer coating and improve the toughness of the outer coating. By introducing HfC nanowires, the coated sample’s cyclic ablation resistance was improved. After cyclic ablation under oxyacetylene flame for 60 s × 3, the mass and linear ablation rates of the coated sample with HfC nanowires were only 0.444 mg/s and −0.767 μm/s, respectively.
研究领域:
材料科学
·
陶瓷涂层
·
航空航天工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Yanlei Li,Haibo Ouyang,Cuiyan Li,Bohan Sun,Tianzhan Shen,Qianqian Chen
Hafnium carbide (HfC) nanomaterials hold significant potential for enhancing the performance of ultra-high temperature ceramic matrix composites. However, achieving the synergistic optimization of their mechanical and ablation resistance properties through controllable synthesis remains a challenge. To address this issue, this study employed a nickel-catalyzed pyrolysis method using hafnium tetrachloride (HfCl 4 ) and furfuryl alcohol as precursors. By precisely controlling the catalyst concentration within a carbon/carbon (C/C) preform, the controlled synthesis of HfC nanowires (HfC NWs ) with two distinct diameters (500 nm and 1000 nm) was successfully achieved. Subsequently, corresponding C/C-HfC-SiC composites (denoted as HS-1 and HS-2) were fabricated via the polymer impregnation and pyrolysis (PIP) process. The results demonstrate that the HS-1 composite modified with 500 nm HfC NWs exhibits the most superior performance: its flexural strength was significantly increased by 51.84 % compared to the unmodified sample, and it displayed the best ablation resistance after 60 s of exposure to an oxyacetylene flame. In-depth characterization revealed that this enhancement originates from the dense three-dimensional network formed by the finer nanowires, which effectively traps ceramic particles and facilitates the formation of a denser, more protective oxide layer. This work elucidates the critical role of nanowire diameter control and provides valuable insights for designing high-performance composites for extreme environments.
研究领域:
材料科学
·
陶瓷基复合材料
·
纳米材料
·
高温材料工程
✓ 已验证
产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2017
·Vol. 7
·期 24
·6000-6012
·
IF 5.773
Wenfeng Han,Chunpeng Zhang,Haili Wang,Shenglan Zhou,Haodong Tang,Luteng Yang,Zhikun Wang
Hydrofluorocarbons (HFCs) which are usually potent greenhouse gases are regulated by the Montreal Protocol and its amendments, especially the recent Kigali Amendment. Dehydrofluorination of HFCs is an efficient route for the conversion of these greenhouse gases to value added and environmentally benign chemicals. Although AlF3 with strong Lewis acidity catalyzes dehydrofluorination, it also favors carbon deposition. MgF2 with weak acidity inhibits coking significantly. Unfortunately, MgF2 sinters dramatically at temperatures below 300 °C leading to the low activity for dehydrofluorination. In the present work, we report that sub-nano MgF2 embedded in carbon fibers and electrospun MgF2 fibers prevent sintering of MgF2 during dehydrofluorination reaction. Via simple and one-step electrospinning and calcination in a N2 (for embedded MgF2) or air (for MgF2 fibers) atmosphere, embedded MgF2 with particle sizes between 3–6 nm and pure MgF2 fibers with diameters of around 100 nm were fabricated. No sintering was observed following reaction at 450 °C. The fine MgF2 particles and MgF2 fibers facilitate the formation of under coordinated Mg species in MgF2 which are the weak acid sites. By embedding MgF2 or fabrication of MgF2 fibers, weak acid sites are increased significantly, while strong acid sites remain almost unchanged. Hence, they show significantly higher reaction rates than MgF2 prepared by precipitation of Mg(CH3COO)2·4H2O with NH4F for the dehydrofluorination of 1,1,1-trifluoroethane (HFC-143a) to VDF (CH2CF2) at 450 °C.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2026
·
IF 4.6
Chenguang Guo,Xingyu Li,En Mei,Junming Liu,Hao Xu,Yuan Chao,Peng Zhang,Zhongyou Que,Lin Zhang,Mingli Qin,Xuanhui Qu
Carbides as typical secondary particles are effective in strengthening tungsten (W) alloys, particularly at elevated temperatures. However, the addition of carbides generally necessitates a higher sintering temperature for W in the powder metallurgy process, resulting in coarsened microstructures and degraded properties. In this study, W-HfC composite nanopowders with a core-shell structure are prepared by a freeze-drying method to overcome the densification barrier caused by HfC during subsequent sintering. The constant-heating-rate sintering experiments demonstrate that the sintering kinetics are independent of HfC content for W-HfC core-shell nanopowders. Utilizing a pressureless two-step sintering (TSS) method at low temperatures, we fabricated a dense W-0.5 wt% HfC alloy with an ultrafine-grained microstructure (average grain size: 420 nm). Benefitting from low-temperature sintering, HfC particles with sizes below 20 nm are uniformly dispersed within the W matrix and exert a significant strengthening effect on W. This study demonstrates that freeze-drying combined with TSS is a promising method for fabricating dispersion-strengthened W alloys with well-controlled microstructure and properties.
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Yiwei Sun,Xiaoli Wei,Fangcao Liu,Bing Liu,Jiaming Zhao,Yubao Bi,Wenfeng Han
Developing effective techniques to produce and stabilize highly active metastable F-Al-O species in HFCs dehydrofluorination system without being over-fluorinated to Al-F is a major challenge. Herein, we report a new strategy for the formation and stabilization of metastable species. Using NaH 2 PO 4 as a P source, phosphoric acid groups are modified to the surface of Al 2 O 3 leading to the fabrication of AlPO 4 /Al 2 O 3 interface. P and Al 2 O 3 bond to form Al-O-P structure at the interface and stabilize F-Al-O in the dehydrofluorination system. Further studies show that AlPO 4 /Al 2 O 3 interface increase the oxygen vacancy content of catalyst and accelerate the conversion of HFC-152a on the catalyst surface. Meanwhile, AlPO 4 /Al 2 O 3 interface improves the surface acidity of Al 2 O 3 , endue a large number of Lewis weak acid sites, reducing the carbon accumulation of catalyst, and improving the stability of catalyst. The activity test showed that AlPO 4 /Al 2 O 3 interface shows high catalytic performance (74.2 %) and excellent stability (50 h) for 1,1-difluoroethane dehydrogenation compared with Al 2 O 3 (30 % and low stability) without P modification.
研究领域:
化学工程
·
环境科学
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2023
·
IF 3.3
Bowen Zhang,Fugang Zhong,Xinchao Qiu,Jianbo Xu,Mengchen Hu,Jun Ou-Yang,Yue Zhang,Benpeng Zhu,Xiaofei Yang,Shi Chen
Hafnium carbide (HfC) whiskers were successfully synthesized by combining hydrothermal and carbothermal reduction. The precursor of HfC whiskers was prepared by the hydrothermal method, subsequently pyrolyzed, and reduced to HfC whiskers at 1500–1700 °C. The synthesis parameters of HfC whiskers at various temperatures, C/Hf molar ratios, and NaF concentrations were investigated in detail. The whiskers with diameters of 1–3 μm and lengths of 50–90 μm were prepared by pyrolyzing the precursors with a C/Hf molar ratio of 6 at 1700 °C. The experimental results and thermodynamic analysis demonstrated that the growth of HfC whiskers was governed by the vapor-liquid-solid (VLS) mechanism. Furthermore, the prepared HfC whiskers were added to the ZrB 2 -HfO 2 coatings on the surface of tungsten-rhenium substrates in different ratios to toughen the coatings. The thermal shock test results indicated that the coatings toughened with HfC whiskers had better thermal shock resistance. In particular, the maximum number of thermal shock cycles that 6%HfC W -ZH could withstand was five times higher than that of W–Re alloy and about one time higher than that of ZH coatings without HfC whiskers. The thermal shock resistance of the ZrB 2 -HfO 2 coatings was significantly improved by adding HfC whiskers.
研究领域:
材料科学
·
陶瓷材料
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2019
·
IF 2.794
Jian Zhang,Ye Tian,Jiawen Zhu,Yi Sun,Guoqiang Luo,Qiang Shen,Lianmeng Zhang
In this study, the W-HfC-Zr composites with various Zr content were fabricated via plasma activated sintering. The relative density, microstructure, microhardness , as well as mechanical properties of these composites were investigated. The W-HfC-Zr composite with 1.0 wt% Zr content had high relative density of 97.56%, exhibited the higher microhardness of 614 Hv, compressive yield strength of 1.85 GPa and bending strength of 880 MPa, which attributing to Zr captured impurity oxygen and generated solid-solution oxide (Hf, Zr)O. The enhancement mechanisms of trace Zr addition on microstructure and mechanical properties were proposed.
✓ 已验证
DOI
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 69
·39284-39290
·
IF 2.936
Youlin Jiang,Dewei Ni,Qi Ding,Bowen Chen,Xiaowu Chen,Yanmei Kan,Shaoming Dong
Nano-crystalized HfC was successfully synthesized based on an aqueous solution-derived precursor using hafnium tetrachloride and sucrose as raw materials. The precursor can be converted to pure phase HfC after pyrolysis at ∼600 °C and subsequent carbothermal reduction reaction at ∼1600 °C, with a ceramic yield of around 46.3%. Reaction mechanisms of the synthesis process are revealed based on FT-IR, TG-DSC, TEM analysis and thermodynamic calculations, etc. The obtained HfC nanoparticles possess an equiaxial shape with an average particle size of ∼73 nm. Oxygen content of the as-synthesized HfC powders is as low as 0.64 wt%, which exists in the form of an amorphous Hf–O–C thin layer covering the surface of the HfC particles. This feasible and promising method for HfC particle synthesis is believed to be suitable for the fabrication of continuous fibers reinforced HfC ceramic matrix composites.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2024
·
IF 6.2
Xiangli Wen,Gong Peng,Pengpeng Bai,Ningyi Yuan,Luo Yue,Yonggang Meng,Yu Tian,Lvzhou Li,Jianning Ding
With the development of deep-sea exploration technology, the technology of fire-retardant hydraulic fluid (HFC) has played an important role in the power transmission of exploration equipment. However, the mechanism of the influence of seawater content on the tribocorrosion behavior of HFC remains unclear. In this study, the effects of different seawater contents on the tribological and corrosive properties of HFC were systematically investigated. The results showed that when the seawater concentration exceeds 30 wt%, a soft Mg-containing reaction film is formed in the friction contact area owing to seawater corrosion, thus effectively improving the sintering load and wear resistance to some extent. By contrast, with increasing seawater concentration, the lubricity declines, the wear intensifies, and the extreme pressure characteristics decrease significantly. The comparative analysis shows that the composition of the wear and corrosion reaction films significantly differs under high-concentration seawater conditions, which is also a key factor affecting the friction and corrosion behavior of HFC. This study provides a direction for the research and development of wear- and corrosion-resistant materials and coatings on the surface of deep-sea exploration equipment.
研究领域:
材料科学
·
腐蚀科学
·
表面工程
✓ 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）