Crystals
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2024
·Vol. 14
·期 3
·279
·
IF 2.4
Yang Wu,Hao Lan,Xiaoming Sun,Zihao Hu,Yonghui Sun,Huifeng Zhang,Chuanbing Huang,Weigang Zhang
HfO2has become a promising thermal barrier coating material due to its similarity in structure and chemical properties with ZrO2and its higher phase structure transition temperature. However, the fracture toughness of HfO2is not ideal, greatly limiting its application. In this report, we find a special sandwich structure of ceramics, comprising a cubic (C) phase /monoclinic (M) phase/cubic (C) phase. The microstructural evolution and mechanical properties of these ceramics were investigated under annealing at 1500 °C. The results indicate that, with an increase in annealing duration, there was a gradual augmentation in the proportion of the monoclinic (M) phase and the fracture toughness increased from 2.18 MPa·m0.5to 2.83 MPa·m0.5after 48 h of annealing, which is higher than many potential TBC materials. The residual compressive stress present in the M phases during the progression of crack propagation served to facilitate the bridging and deflection of cracks. As such, this process led to the alleviation of stress concentration at the crack tip, ultimately enhancing the toughening effect.
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
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2019
·
IF 4.029
Lu Zilong,Yue Jianling,Fu Zeyu,Huang Xiaozhong,Yang Haitang
SiC f /BN/SiC mini-composites comprising single tow SiC fibre-reinforced SiC with chemical vapour deposited (CVD) BN interface layers were fabricated. The mechanical performance and binding strength of the composites and the fibre/interface for the oxidized SiC f /BN/SiC mini-composite samples (oxidation at 1000, 1200, 1300, 1400 and 1500 °C in air for two hours) were investigated by tensile tests and fibre push-out tests, respectively. The value of oxidation mass change was also measured. Some unusual phenomena for the SiC f /BN/SiC mini-composites oxidized at 1000 °C were discovered in this work. The tensile strength reached a maximum value, and the mass gain rate showed as a singular negative value, while the shear strength between the fibre and the matrix was moderate. Scanning electron microscopy, energy dispersive spectrometry, infrared spectroscopy and X-ray diffraction characterization methods were used to reveal the microstructural evolution and investigate the unusual phenomenon during oxidation procedures. This work will provide guidance for predicting the service life of SiC f /BN/SiC composite materials and may enable these materials to become a backbone for thermal structure systems in aerospace applications .
研究领域:
材料科学
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高温复合材料
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航空航天材料
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表面工程
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结构表征
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2018
·
IF 3.779
Jun Cheng,Xiaozhou Wang,Jun Wang,Hao Wang,Shengxuan Hu
Precursors with different nitrogen contents were synthesised using hafnium (IV) chloride (HfCl 4 ), dicyandiamide (DICY) and triethylamine (Et 3 N) as raw materials and were used for preparing Hf-based nanocomposites. The synthesis, ceramic conversion and microstructural evolution of HfC-based nanocomposites derived from precursors with different nitrogen contents were investigated. The results indicate that the composition of the synthesised precursors can be controlled by adjusting the molar ratio of HfCl 4 and dicyandiamide. Pyrolysis of the precursors at 1200 °C led to the formation of Hf 2 CN or HfN-based ceramics. As the nitrogen content of the synthesised precursors increased, the Hf 2 CN crystallites present in the ceramics annealed at 1200 °C gradually transformed to HfN. Furthermore, at 1600 °C, the HfN and Hf 2 CN phases gradually converted to HfC(N). The results also indicate that nitrogen favours the sintering of the obtained nanocomposites. The HfC-based ceramics should be promising for application as high-performance composite ceramics.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
eTransportation
·
2021
·
IF 0
Yu Leng,Daijun Yang,Pingwen Ming,Cunman Zhang
Reliable assessment of corrosion resistance is critical in seeking the appropriate materials for bipolar plate (BPP) while corrosion of BPP still remains a key challenge in proton exchange membrane fuel cell (PEMFC). In this work, the effects of accelerated and simulated testing conditions as well as potential on corrosion behaviours and microstructure evolutions of stainless steel bipolar plate are studied with SS316L by potentiodynamic and potentiostatic tests, and electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Moreover, the rationalities of evaluating corrosion resistance of materials for BPP under accelerated and simulated testing conditions with different potentials are analyzed based on electrochemical tests and corrosion mechanisms of SS316L. The results reveal that pitting is the main corrosion mechanism for SS316L in the simulated or real PEMFC working conditions. However, the dominant corrosion mechanisms are changed to intergranular and uniform corrosion at the potentials of 1.15 V–1.55 V (vs. SHE), respectively, when tests are performed in accelerated conditions with pH = 0.3. The results indicate that the accelerated conditions may be inappropriate for evaluating corrosion resistance of materials for BPP, especially at higher potentials.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Jiaqi Ruan,Zongze Lv,Yong He,Xin Huang,Jingyu Ran,Changlei Qin
High-temperature CO 2 adsorption has an attractive prospect in reducing CO 2 emissions efficiently. As the core of CO 2 adsorption technology, sorbents suffer from a well-known problem of capacity degradation as a result of sintering during cyclic CO 2 adsorption and desorption at high temperatures. This work aims to understand the microstructural evolution of Li 4 SiO 4 , one of the most typical and promising sorbents, during CO 2 capture. In-situ Transmission Electron Microscopy was used to directly capture the morphological variation of Li 4 SiO 4 sorbents. Comprehensive characterization techniques were adopted to quantify microstructural parameters of Li 4 SiO 4 under different conditions . The real-time shrinkage of Li 4 SiO 4 particles was demonstrated and equations on grain growth, specific surface area reduction, and pore volume evolution were established. The work can not only reveal the reason for the reduction of CO 2 capacity, but provide a theoretical guidance for the development of sintering-resistant CO 2 sorbents.
研究领域:
材料科学
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环境科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Qi Ding,Zikang Zhan,Zongbo Zhang,Ziheng Wei,Zhi Cheng,Jie Gao,Yudong Xue,Lianjun Wang,Yuchi Fan,Wan Jiang
In this work, SiBCN fibers with excellent electromagnetic wave (EMW) absorption performance were fabricated using electrospinning technology, followed by curing, pyrolysis, and heat treatment. Microstructure evolution and EMW absorption performance of SiBCN fibers after heat treatment at 1200–1600 °C were investigated. After heat treatment at 1200 °C, the conductive turbostratic C was precipitated from amorphous SiBCN fibers, resulting in minimum reflection loss (RL min ) reaching −63 dB and efficient absorption bandwidth (EAB) reaching 5.2 GHz. While turbostratic C and nano-SiC grains were simultaneously precipitated from SiBCN fibers heat treated at 1400 °C, and the RL min reached −67 dB. The excellent EMW absorption performance of SiBCN fibers was mainly attributed to the synergistic effect of conductive loss, dipole polarization, and interfacial polarization. This work can guide the fabrication of high-performance EMW-absorbing ceramic fibers.
研究领域:
材料科学
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电磁学
✓ 已验证
DOI
高影响因子
MATERIALS CHARACTERIZATION
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2020
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IF 3.562
Yongxiang Zheng,Chengji Deng,Jun Ding,Hongxi Zhu,Chao Yu
An innovative approach was developed for the fabrication of AlN-Al 2 O 3 porous ceramic by heat-treating Al 4 O 4 C porous ceramic under a flowing nitrogen atmosphere. The effects of sintering temperature on phase and microstructural evolution changes were investigated. The results indicated that phase evolution of the nitridation of Al 4 O 4 C porous ceramics was significantly different from dense Al 4 O 4 C ceramics. AlN-Al 2 O 3 porous ceramic produced using this new method had a homogeneous local chemical composition with the two phases tightly combined in the composite material. Possible reaction mechanisms for the fabrication of AlN-Al 2 O 3 porous ceramic are discussed by considering reactions at the initial and later stages during the nitridation process.
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
Materials Research Express
·
2024
·Vol. 11
·期 7
·075101
·
IF 1.8
Lina Zhan,Yao Zhang,Xuan Zhang,Yuzhibiao Xia,Yao Liu
The densification mechanism of CeO2 doped Si3N4 ceramics during spark plasma sintering (SPS) was investigated. The sintering process was observed to undergo significant densification at the intermediate stage of sintering (1435 °C–1816 °C), and the density and grain size of CeO2 doped Si3N4 ceramic were found to be greater than those of pure Si3N4 ceramic under the same sintering conditions. To determine the densification mechanism, a creep model was utilized to determine the densification mechanism which could be interpreted based on the values of the stress exponent (n) and the apparent activation energy (Qd). The results revealed that the Qd of pure Si3N4 (381.15 kJ mol−1) is higher than that of Si3N4-CeO2 powder (265.61 kJ mol−1). Moreover, the stress exponent n of Si3N4-CeO2 powder (1.12–1.33) was higher than that of pure Si3N4 powder (1.00–1.18). This can be attributed to the fact that the addition of CeO2 resulted in the formation of a liquid phase at the grain boundary which leading to a shift in the controlling mechanism from grain boundary diffusion to grain boundary sliding.
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
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Ling Pan,Ling He,Zibo Niu,Peng Xiao,Wei Zhou,Yang Li
In this work, Yb 4 Hf 3 O 12 ceramic, a typical rare-earth hafnate, was exposed to water vapor with Al(OH) 3 impurities at 1400 ℃, and microstructural evolution and corrosion mechanisms were investigated. The long-term corrosion can be divided into initial hydration and gasification of Hf 4+ and steady-state corrosion after the formation of Al 5 Yb 3 O 12 . In the initial stage, Hf 4+ and the surrounding O 2- tend to be hydrated and then volatilized in the form of Hf(OH) 4 , causing a metastable state of Yb 4 Hf 3 O 12 on the surface. Besides, the preferential corrosion of small grains, grain boundary, and specific crystal plane on the surface and sintered and densified grains result in varied corrosion behavior from the early linear law to the later parabolic law. In the steady-state corrosion stage, due to the consumption of Hf 4+ , more vacancies promote bonding and diffusion of Al 3+ to form corrosion product (Al 5 Yb 3 O 12 ), and during this stage, regrowth and shedding of the corrosion layer reach a dynamic balance.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
产品关联
DOI
高影响因子
Journal of Manufacturing Processes
·
2022
·
IF 5.684
Lizheng Zhang,Hao Liu,Haihua Yao,Yong Zeng,Jimin Chen
3D printing technology was introduced into the manufacturing of ceramic components. To obtain a new lightweight multifunctional structure with novel structure and excellent performance, and promote the deep combination of additive manufacturing and optimization design, ZrO 2 (3Y)/Al 2 O 3 hollow lattice structure ceramics with two kinds of high precision and different porosity were prepared by vat photopolymerization in this paper, and the process optimization, microstructure evolution , and performance were studied. The hollow lattice structure with good molding accuracy and porosity of 35 %–55 % was prepared by component design, optimization of slurry, degreasing, and sintering process , which effectively avoided the ceramic cracking and collapse caused by resin volatilization. When the Al 2 O 3 content was 6 wt%, dense ZrO 2 (3Y)/Al 2 O 3 ceramics with grain refinement, excellent microhardness , and fracture toughness were obtained. The relationship between lattice structure and compressive strength was analyzed by simulation and compressive test . The results show that the compressive strength of the two hollow lattice structures decreases with the increase of porosity. The maximum compressive strength of 35 %-face-centered cubic (FCC) hollow lattice structure is 326 MPa, which is significantly higher than that of body-centered cubic (BCC) structure (240 MPa) with the same porosity. The hollow lattice ceramic structure with good comprehensive performance and lightweight will lay a foundation for the application of industrial heat insulation , high temperature catalysis, and purification carrier in the future.
研究领域:
材料科学
·
先进制造
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2021
·
IF 9.078
Zhen Lu,Dekai Liu,Chengcheng Shi,Han Xiao,Wei Liu,Shaosong Jiang
NiAl intermetallic compounds have attracted the attention of researchers in the field of high-temperature structural materials, but their poor room-temperature ductility and insufficient high-temperature strength crying out for solutions have hindered their practical application. To solve these problems, a novel 3-dimensional network structure-reinforced NiAl-based composite was designed by hot presing sintering sinter with pre-alloyed powders. The 3-dimensional network structure was composed of discrete nearly spherical HfO 2 and rod-shaped HfRe 2 . The mechanical properties of the composites were closely correlated with the distribution of the 3-dimensional network structure in the matrix, which was controlled by the sintering temperature and holding time. A microstructure with a desirable 3-dimensional network structure distribution and the best comprehensive mechanical properties was produced at 1375 °C/60 min. The microstructural evolution along with the strengthening and toughening mechanisms were discussed in detail. The increase in the high-temperature strength was mainly attributed to the pinning effect of the 3-dimensional network structure on dislocations and the restraining effect on the sliding and rotation between the matrix grains, while the increase in room-temperature ductility was mainly due to the grain refinement and hindering of crack propagation by the 3-dimensional network structure. In this paper, the development of a novel low-density NiAl-based composite with a 3-dimensional network structure improved both the strength and ductility, providing design ideas for the application of NiAl-based materials.
研究领域:
材料科学
·
力学
✓ 已验证
DOI
高影响因子
Materials Today Physics
·
2022
·
IF 11.021
Wan Ting Dai,Zhen Hua Xie,Yu Bin Ke,Yang You,Min Zhi Rong,Ming Qiu Zhang,Chun Yong He,Han Qiu Jiang,Hua Yang
To understand the molecular origin of the significantly improved mechanical properties of the newly emerged reversibly interlocked polymer networks (ILNs), which are composed of two dynamically crosslinked polymers regardless of their miscibility, the present work employs small angle neutron scattering (SANS) technique to study the microstructural evolution of the materials during stretching. Accordingly, polyacrylate networks containing reversible Diels-Alder (DA) bonds and polyether networks containing reversible Schiff base bonds are synthesized and then interlocked together through topological rearrangement of the two single networks. By using deuterated acrylate monomers , furthermore, the single networks with DA bonds are labeled, providing the model ILNs with necessary contrast for the SANS measurements. The strain-dependent SANS profiles and 2D SANS patterns of the ILNs reveal that the latter maintain the homogeneity after extension. It means that the two parent single networks are simultaneously deformed because the interlocking sites act as movable crosslinkages, so that the chains conformation can be modulated and the applied stress can be effectively transferred. When relative movement of the neighboring molecular chains occurs, a great number of molecular chains in the interlocked polymer networks are able to be tightened at the same time, and more mechanical energy can be dissipated by internal friction in the process. The findings reveal that the mechanical enhancement results from the unique interlocked structure, and provide guidance for the rational design of high-performance multi-component polymer materials.
研究领域:
材料科学
·
高分子化学
✓ 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）