Materials
·
2023
·Vol. 16
·期 12
·4426
·
IF 3.4
Guang Zeng,Ping Xu,Chen Zeng,Qizhong Huang,Zhean Su
HfCxN1−xnanoparticles were synthesized using the urea-glass route, employing hafnium chloride, urea, and methanol as raw materials. The synthesis process, polymer-to-ceramic conversion, microstructure, and phase evolution of HfCxN1−x/C nanoparticles were thoroughly investigated across a wide range of molar ratios between the nitrogen source and the hafnium source. Upon annealing at 1600 °C, all precursors demonstrated remarkable translatability to HfCxN1−xceramics. Under high nitrogen source ratios, the precursor exhibited complete transformation into HfCxN1−xnanoparticles at 1200 °C, with no observed presence of oxidation phases. In comparison to HfO2, the carbothermal reaction of HfN with C significantly reduced the preparation temperature required for HfC. By increasing the urea content in the precursor, the carbon content of the pyrolyzed products increased, leading to a substantial decrease in the electrical conductivity of HfCxN1−x/C nanoparticle powders. Notably, as the urea content in the precursor increased, a significant decrease in average electrical conductivity values was observed for the R4-1600, R8-1600, R12-1600, and R16-1600 nanoparticles measured at a pressure of 18 MPa, yielding values of 225.5, 59.1, 44.8, and 46.0 S·cm−1, respectively.Keywords:HfCxN1−x;pyrolysis;ultra-high-temperature ceramics;nanoparticles
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
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
·
2012
·
IF 2.003
Rujie He,Ping Hu,Xinghong Zhang,Chen Liu
Complex-shaped ZrB 2 –SiC ultra high temperature ceramic components were successfully fabricated by gelcasting technique and pressureless sintering. When 0.4 wt% poly(acrylic acid) (PAA) was used as dispersant and the pH value was 10, an aqueous ZrB 2 –SiC–B 4 C–C slurry with a high solid loading up to 50 vol% but low viscosity (3.1 Pa s at 60 s −1 ) was prepared. For gelcasting process, the suitable monomers content (AM and MBAM) and the mass ratio of monomers (AM/MBAM) were selected as 3 wt% and 15:1, respectively. After pressureless sintering at 2100 °C for 2 h, ZrB 2 –SiC ceramics (using B 4 C and C as sintering additives) finally achieved about 98% density. Investigation of the mechanical properties revealed a flexural strength of 405±27 MPa and a fracture toughness of 4.3±0.3 MPa m 1/2 . Complex-shaped ZrB 2 –SiC ceramic components with homogeneous microstructure were also successfully produced. This study confirms that gelcasting is a reliable process for the fabricating of complex-shaped ultra high temperature ceramic components with satisfied properties.
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
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.
研究领域:
材料科学
·
制造工程
✓ 已验证
产品关联
DOI
高影响因子
THEORETICAL AND APPLIED FRACTURE MECHANICS
·
2020
·
IF 3.021
Anzhe Wang,Xinyuan Zhao,Mingxu Huang,Zhen Zhang,Lishuai Xie
In this paper, a systematic study on the effect of flaws on flexural strength of ultra-high temperature ceramics (UHTCs) was carried out by using three typical materials (i.e., ZrB 2 , ZrB 2 -SiC and ZrB 2 -SiC-G ceramics) containing micro-sized flaws with controllable sizes, shapes as well as orientations. Depending on the flaw sizes and orientations, different fracture modes were analyzed by SEM observation and theoretical calculation. Based on Emmerich’s hole/strength model and the maximum strain-energy release-rate mixed-mode fracture criterion, a universal flaw/strength model was developed to describe the flexural strength of flawed UHTCs after taking both material properties and flaw’s geometries into account, and compared well with the experimental data in both mode I and mixed-mode conditions. Prediction results of the proposed model have further verified that substantially consistent with the flexural strength reports of UHTCs in the literature as well as the theoretical strengths calculated from the elastic modulus, which means that the proposed model has a great potential in guiding the design of high-strength ceramics in full-scale (from atomic-scale to macro-scale).
研究领域:
材料科学
·
力学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Ping Hu,Yuan Cheng,Peng Wang,Xiang Guo,Chen Ma,Qiang Qu,Xinghong Zhang,Shanyi Du
Inspired by natural exoskeleton composites in arthropods consisting of regularly oriented fibrous chitin within continuous matrices, a novel rolling compacted method was developed to enable controlled orientation of carbon fibers in UHTCs. Using rolling compaction, carbon fibers were arranged in ZrC-SiC matrix along highly consistent direction, in which ceramic powders were uniformly introduced into intrafascicular and interfascicular spaces of fiber bundles. The fabricated C f /ZrC-SiC composite revealed an extendedly graceful fracture pattern and stably impeded crack propagation with a flexural strength and fracture toughness at 227 ± 3 MPa and 5.46 ± 0.14 MPa m 1/2 . An exceptional work of fracture of 3244 ± 76 J/m 2 was achieved, one order of magnitude higher than those of UHTCs, attributed to toughening mechanism of oriented carbon fibers such as fiber pull-out and bridging accompanied by crack deflection and termination. This work provides an easily feasible way to tailor mechanical performance for fiber-reinforced composites through site-specific optimization of fiber orientation .
研究领域:
材料科学
·
仿生学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Kai Zhao,Fang Ye,Laifei Cheng,Jie Zhou,Yucong Wei,Xuefeng Cui
Ultra-high temperature ceramics (UHTCs) have become a vital candidate material system for thermal protection systems in aerospace applications. However, high thermal conductivity and high density are the main obstacles to the application of UHTCs. It is a promising solution to prepare porous UHTCs using UHTC hollow microspheres (HMs) as a pore-forming agent. In this work, UHTC (ZrC, TiC, and HfC) HMs are successfully synthesized using carbon hollow microspheres (CHMs) as a template to react with metal powders in molten salt. The diameter of ZrC HMs is about 1 μm and the wall thickness is about 100 nm. The density of each microsphere and the volume fraction of ZrC are 3.36 g/cm3 and 48.42 vol %, respectively. The morphology, microstructure, and phase composition of the obtained ZrC HMs were characterized. The formation mechanism of the UHTC HMs was discussed. Porous ZrC ceramics were prepared using ZrC HMs as a pore-forming agent. The density and thermal conductivity of the porous ZrC ceramics are 3.12 g/cm3 and 1.82 W/(m·K), respectively, which are 53.64 and 91.12% lower than the density and thermal conductivity of dense ZrC ceramics, respectively. The results indicated that ZrC HMs are promising as pore-forming agents or a matrix for lightweight thermal insulation and high-temperature resistance applications in ultra-high temperature environments.
研究领域:
材料科学
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航空航天工程
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2023
·
IF 3.3
Shibin Wu,Keru Song,Jianwen Wang,Siyu Huang,Fengyue Shi,Guangdong Zhao
ZrB 2 –SiC ceramics were successfully prepared via sol–gel method using phenyltrichlorosilane, borane dimethyl sulfide , and zirconium tetrachloride in stoichiometric amounts as the raw materials. The macromolecular network structure formed after the sol–gel process was investigated via Fourier transform infrared (FT–IR) spectroscopy. The phase evolution of the ZrB 2 –SiC ceramics were analyzed by FT–IR spectroscopy, X–ray diffraction, and transmission electron microscopy , whereas morphological and elemental analyses were performed using scanning electron microscopy. In particular, the change in phase composition was monitored after the pyrolysis from 1400 to 1500 °C, and the heat treatment of BZ6 precursor at 1500 °C enabled one to produce the ZrB 2 –SiC ceramic with a homogeneous crystal phase distribution. Therefore, the controllable microstructure adjustment of the ceramic phase composition could be achieved and a new way was paved for the structural and functional applications of ultra–high–temperature ceramics (UHTCs) series.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2023
·Vol. 16
·期 17
·5983
·
IF 3.4
Tingyu Zhao,Zhengxiang Zhong,Xuanfeng Zhang,Jiangfeng Liu,Wenfang Wang,Bing Wang,Li Liu
The development of high-temperature organic adhesive for bonding ultra-high-temperature ceramics with excellent thermal shock resistance has important significance to thermal protection systems for high-temperature environment application. In this study, high-temperature organic adhesive (HTOA) with carbon-fiber-SiC nanowires (CF-SiCNWs) binary phase enhancement structure was prepared. The method is that the SiCNWs grow on the chopped carbon-fiber surface and in the matrix of modified HTOA during high-temperature heat treatment with the help of a catalyst by a tip-growth way and with a vapor–liquid–solid (V-L-S) growth pattern. The results showed that the CF-SiCNWs binary phase enhancement structure plays a significant role in improving thermal shock resistance of high-temperature organic adhesive. The retention rate of the joint bond strength for the bonding samples after 20 cycles of thermal shock testing reaches 39.19%, which is higher than for the ones without CF, whose retain rate is only 6.78%. The shear strength of the samples with the CF-SiCNWs binary phase enhancement structure was about 10% higher than for those without the enhancement structure after 20 cycles of thermal shock.Keywords:adhesive;thermal shock resistance;ultra-high-temperature ceramics
研究领域:
材料科学
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胶粘技术
·
高温材料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2024
·Vol. 59
·期 22
·9941-9951
·
IF 3.5
Zeng Dawei,Zhou Jiaxin,Wu Zhen,Sun Luchao,Wang Jingyang
Ultra-high temperature ceramics (UHTCs) are considered as promising thermal insulation materials applied in ultra-high temperature environments (> 2000 °C). However, the high thermal conductivity and high density limit their further development and application. Herein we adopt the strategies of introducing porous structure and high-entropy effect to solve the above problems. Thus porous high-entropy (Zr 0.25 Hf 0.25 Nb 0.25 Ti 0.25 )C ceramics were prepared. In order to obtain the uniform pore structure and high mechanical property, the camphene-based freeze-casting method was used in this study. The as-prepared porous samples exhibit high porosity of 92.01–73.57% and homogeneously interconnected pore structure with average pore size of 40.8–19.6 μm. Besides, this work realizes the aims of lightweight (0.65–2.15 g/cm 3 ) and low thermal conductivity (0.29–1.53 W/(m·K)). More importantly, porous samples still have the merit of high compressive strength (0.38–29.02 MPa) due to the even microstructure. The results show that highly porous high-entropy (Zr 0.25 Hf 0.25 Nb 0.25 Ti 0.25 )C with good overall properties can be an excellent candidate material for ultra-high temperature thermal insulation.
研究领域:
材料科学
·
陶瓷
·
热工学
·
机械工程
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2025
·
IF 3.8
Xiaoyu Wang,Dewei Ni,Bowen Chen,Feiyan Cai,Yang Hu,Yanmein Kan,Yusheng Ding,Shaoming Dong
In this work, a novel multi-anion ultra-high temperature ceramic (UHTCs) powder—Hf 0.8 Zr 0.2 B 0.1 C 0.5 N 0.4 , was designed and synthesized by carbothermal and borothermal reduction above 1400°C using B 4 C, carbon black, and N 2 as boron, carbon, and nitrogen sources, respectively. The as-synthesized Hf 0.8 Zr 0.2 B 0.1 C 0.5 N 0.4 powder has a rock-salt crystal structure and high compositional homogeneity, with lattice constant of 4.602 Å. It has an average particle size of ∼0.13 µm and low oxygen content of ∼0.43 wt%. This work not only expands the category of UHTCs but also opens a new insight to develop and design UHTCs with multi-anion and cation structures for performance optimization.
研究领域:
材料科学
·
陶瓷
·
无机合成
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2022
·
IF 11.322
Zizhang Zhan,Wei Sun,Shuaishuai Zhang,Qingbo Wen,Hongbo Zhang,Xiang Xiong
A (AlCrMg) x (PO 4 ) y /MgO composite(APMC) was prepared based on the acid–base reaction between MgO and chromium aluminum phosphate solution for thermal protection and insulation applications at ultrahigh-temperatures up to 2400 °C. The compositions, formation mechanisms, microstructure, mechanical properties , thermal conductivity and ablation resistance of the composite were systematically investigated. The results show that the (AlCrMg) x (PO 4 ) y /MgO composite can be consolidated in different shapes at room temperature. The compressive strength of the as-prepared porous composites is higher than 20 MPa due to the macromolecular network structure, and it can be further improved to 42 MPa via thermal treatment. After ablation by an oxyacetylene flame at 2400 ± 70 °C for 60 s, the mass and line ablation rates of the composite were 0.0195 g/s and 0.43 × 10 −3 mm/s, respectively, which are comparable to those of ultrahigh-temperature ceramics. The excellent ablation resistance can be attributed to the in situ formation of a dense protective layer composed of spinel MgCr 2 O 4 and MgO phases. Interestingly, during ablation at 2400 °C the back-side temperature of the 15 mm-thick sample was lower than 130 °C, suggesting outstanding thermal insulation performance. The temperature gradient leads to the formation of a gradated porous structure which reduces the overall thermal conductivity of the composite.
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
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Hanwen Zhang,Zhen Wang,Kewei Li,Xian Dang,Mengen Hu,Yue Li,Shuxin Li,Ming Li,Zhulin Huang,Xiaoye Hu
Comprehensive performance of ultra-high temperature ceramic composites is predominantly governed by purity, morphology and crystallinity of HfB 2 powders. Nevertheless, achieving controllable synthesis of high-quality HfB 2 ceramic powders remains challenging due to insufficient mechanistic insights into the evolution and growth of powder morphology. In this work, we systematically investigate the effects of diverse carbon sources on the morphology and crystallinity of HfB 2 powders during carbothermal reduction. The results demonstrate that the graphitization degree of carbon sources directly governs whether HfB 2 powder exists in particle or rod-like morphology. Microstructural evolution analysis indicates that the morphological differentiation in HfB 2 powders is predominantly determined by the graphitization degree of the carbon source, which directly controls the oriented attachment of HfO 2 particles in precursors and modulates the reaction temperature during subsequent carbothermal reduction processes. The elevated graphitization degree promotes a more orderly arrangement of HfO 2 nanograins. The HfB 2 powders maintain the anisotropic rod-like morphology inherent in their HfO 2 precursors throughout the growth process, resulting in high-crystallinity, rod-shaped ceramic powders. These crystalline, rod-shaped powders display remarkable antioxidant properties; their mass fraction decreases by only 2.25 % following non-isothermal oxidation at 1000 °C. This research holds significant implications for developing controllable preparation methods for ceramic powders of different morphologies and provides a theoretical foundation for enhancing the performance of ultra-high temperature ceramic materials.
研究领域:
材料科学
·
陶瓷
·
纳米技术
·
热还原
·
表面化学
✓ 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）