IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
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2024
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IF 2.9
Qi Li,Boxue Du,WenBo Zhu,Xiaoxiao Kong
In this article, a simulation model of 110 kV cable termination based on COMSOL is established, and electro thermal coupling characteristics at different temperatures are simulated. Obvious uneven thermal stress distribution inside the termination is found at temperatures below −20 ∘ C, due to the difference in thermal expansion coefficients between different materials. Stress concentration at the interface between the metal insert and epoxy resin occurs. Tensile stress along the direction of the electric field in the epoxy increases as the temperature decreases, with a maximum value of 66.7 MPa at −40 ∘ C. The electrical treeing and partial discharge (PD) characteristics are investigated in epoxy resin under various thermal stress conditions. It is found that the electrical tree growth is accelerated under low temperatures, which is attributed to the increase in thermal stress and decrease in the toughness of the epoxy bushing. In such circumstances, the electrical tree growth rate is greatly increased, frequently accompanied by a sudden enhancement in PDs and expansion of deterioration channels, which is proved by a phase field model considering the induced thermal stress.
研究领域:
电气工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2019
·Vol. 30
·期 15
·14424-14429
·
IF 2.195
Kuang Lingtong,Dai Ying,Pei Xinmei,Chen Wen
BaNb x Ti 2–x O 5 (x = 0, 0.002, 0.004, 0.006, 0.008, 0.01) thin films were deposited on the Pt(111)/Ti/SiO 2 /Si substrates using the sol–gel method. The effect of Nb 5+ substitution on the electric properties of BaNb x Ti 2–x O 5 films was investigated. Diffuse phase transition was observed in all the thin films. The relationship between the dielectric constant and temperature of these films showed a wide platform and no frequency dependence. For the film with x = 0.006, an abnormally broadened dielectric platform was obtained in the temperature range of 200–400 °C, and its value fluctuated in the range of 350 ± 10. The research showed that Nb-doped and thermal stress contributed greatly to this abnormally broadened platform of ε(T) curve. The substituting Nb 5+ in BaTi 2 O 5 thin films caused small microscopic composition fluctuation, which enhanced the degree of diffusion phase transition of the films. And the thermal stress on the films caused inhomogeneous polarization of the surface and center of the films, resulting in a change in phase transition behavior. In addition, the BaNb x Ti 2–x O 5 thin films with high dielectric constant at high temperatures were successfully obtained, which were beneficial to the application of BaTi 2 O 5 films under high temperature conditions.
研究领域:
材料科学
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物理学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2024
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IF 3.8
Ke Xiang,Hui-Hui Ping,Zhen-Liang Xu,Liwei Zhuang,Yong-Jian Tang
Heat curing is an essential step for industrial-scale fabrication of polyamide nanofiltration membranes, which can improve the membrane stability and promote the membrane element encapsulation feasibility, but thermal stresses cannot be avoided during this process. In this study, oven and microwave were used to cure nanofiltration membranes, and the results showed that compared with oven heat curing, the flux dispersion of nanofiltration membranes cured using microwave heat curing was reduced from 0.318 to 0.093, and its Na2SO4 rejection dispersion was reduced from 0.063 to 0.005, providing a tremendous improvement in the uniformity of nanofiltration membranes. The effect of the thermal stress distribution on the uniformity of nanofiltration membranes during heat curing was elucidated by numerical simulations. The fast microwave heating speed and uniform temperature distribution reduced the defects of the PA layer due to uneven thermal stress distribution. In conclusion, this study demonstrated the effect of thermal stress on membrane uniformity in different thermal curing modes, which provides good prospects for the application of microwaves in the field of nanofiltration membranes.
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2022
·
IF 4.865
Zefei Zhang,Hao Chen,Yingqin Wang,Gang Wang,Lihong Li,Min Zhong,Hao Bai
Low melting point metals, such as copper, are often used as high-temperature cooling equipments and endure harsh environments during operations. This usually leads to reduced service life and reliability. To address this problem, a protective coating was prepared on copper via a slurry method. However, due to the low melting point of copper, solid-state sintering was applied. Therefore, during this process, the defects generated in the ceramic coating could affect the performance of the coating. To reduce the defects, a series of ceramic coating samples using sodium silicate water glass (SSWG) as the binder were prepared, changing the SSWG-to-aggregate mass ratio (SAMR) for each sample. The results showed that they were all related to the SAMR, and there was an optimal SAMR with minimum defects and favourable performance. The non-optimized SAMR lead to more internal defects, that is, microfractures and pores in the coating, resulting to a decline in the coating performance. By identifying the types of defects and quantifying them, the relationship between the SSWG and the generation of defects was studied, and the effect of the defects on the performance of the ceramic coating was analysed in detail. The research presented in this paper provides a method for the improvement of ceramic coatings by optimising the key factors that is the SAMR in solid-state sintering. The effect of thermal stress on the formation of microfracture defects during the sintering was investigated by experiments and simulation. It is found that with increase of sintering temperature , the thermal stress inside the coating increases gradually, resulting in more generation of microfracture defects inside the coating. The inhibition effect of SSWG on thermal stress during the sintering process was verified.
研究领域:
材料科学
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表面工程
✓ 已验证
产品关联
DOI
高影响因子
CARBON
·
2022
·
IF 11.307
Shixiang Zhou,Li Yao,Tong Zhao,Hui Mei,Konstantinos G. Dassios,Laifei Cheng,Litong Zhang
Chemiresistive SiOC Negative Poisson's ratio structures for gas detection under thermal and pressure loading were constructed by vat photopolymerization and surface sensitization. Metal-organic framework-derived SnO 2 nanocubes modification provided the structures with sensing capability, while the high deformation-resistant SiOC substrates protected the integrity and connectivity of the sensing layer. The resulting SnO 2 /SiOC sensing structures exhibited high selectivity to formaldehyde vapor and showed a response value of 3.6 to 100 ppm formaldehyde vapor. The structures also had a short sensing delay with the response and recovery times of 32 s and 41 s, respectively. Besides, the independent deformation of the units maintained the dimensional accuracy and avoided thermal fatigue failure of the structure at the working temperature by dispersing the thermal stress, at which the coefficient of thermal expansion reached 0.71 × 10 −6 /K, revealing a near-zero expansion behavior. Meanwhile, the mechanical performance can be adjusted by structure optimization, and the compressive strength and Young's modulus of the structure reached 51.25 MPa and 5.14 GPa, respectively. Taking advantage of the strengthened and self-adaptive design, the structure exhibited high load-carrying capacity and low thermal expansion performance, providing a facile strategy for highly stable gas detection under complex loading environments.
研究领域:
材料科学
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传感器技术
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
RARE METALS
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2025
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IF 11
Dong Bo-Long,Li Hao-Song,Dong Chuan-Qi,Li Xiang-Ji,Zhu Yi-Chen,Fang Yi,Fu Bi-Cheng,Jung Seung-Boo,Zhu Wen-Bo,Li Ming-Yu
Silver paste is widely used in power electronics as a die-attach material owing to its low-temperature sinterability, high melting point, and excellent electrical and thermal conductivities in sintered joints. However, owing to the mismatch in the coefficient of thermal expansion (CTE) between the joints and chip, the high Young’s modulus of sintered silver hinders the mitigation of the high thermal stress generated during the operation of power modules, which increases the susceptibility of sintered joints to cracking, thereby leading to potential failure. This study developed a facile approach to synthesizing bayberry-like Ag microparticles (AgMPs) through the in situ assembly of silver nanorods, resulting in a uniform distribution of nanoscale structures and mesopores on the particle surface. These particles exhibited a high specific surface area of 2.5389 m 2 ·g −1 , which enhanced their sintering activity, enabling sintering to occur at 149.7 °C. Furthermore, the porous structure of the AgMPs effectively reduced the density of joints formed by sintering AgMP paste, thereby lowering the Young’s modulus of the joints. The small grain size and intricate internal substructure of the joints yielded high shear strength, which reached 112.50 MPa at 250 °C. The Young’s modulus could be adjusted, and the pores provided by the AgMPs maintained the Young’s modulus within a low range (15.11–29.61 GPa), effectively mitigating thermal stress. These new bayberry-like porous AgMPs offer a promising option for die-attach materials in electronic packaging. Graphical abstract
研究领域:
材料科学
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电子封装技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
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2024
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IF 8.1
Ming Huang,Fenglin Wang,Haijun Mao,Zhuofeng Liu,Wei Li,Weijun Zhang,Xingyu Chen
Excessive thermal stress in the glass-ceramics to metal seals (GCtM) is known to be inimical to the reliability of the related electrical components and thus typically avoided during the sealing process. Quartz, a linear high-expansion material, has long attracted extensive attentions in GCtM seals, ascribed to its ability to ameliorate the thermal stress in the sealing component. However, the quartz crystallization in the lithium silicate recrystallization glass-ceramics need for a series of complex and cumbersome thermal profiles, especially including a rapid cooling process (>70 °C/min), in the conventional method. Here, we disclose a key finding that a small amount of quartz seed could promotes quartz crystallization at a slower cooling rate and higher temperatures. To counter the problem mentioned above, a thermal strain offset strategy is proposed, which embodies a model to predict the thermal expansion behaviors at different temperatures and the controlled growth of quartz. Consequently, a novel glass-ceramics with near-linear thermal strain have been obtained, notably through a facile and high-efficient thermal profile. More surprisingly, the improved sealing glass exhibits a fluidity similar to that of the original material and the distinctive ability to ameliorate the thermal stress at elevated temperature. This work sheds light on developing high-reliable and cost-effective manufacture method for industrial production of the related electronic component.
研究领域:
材料科学
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电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2018
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IF 3.779
Anzhe Wang,Ping Hu,Cheng Fang,Dongyang Zhang,Xinghong Zhang
The effects of cooling rate and initial temperature on thermal shock behavior of ZrB 2 -SiC ceramic were studied by water spraying method with a thermocouple real-time temperature acquisition technique for the first time. It was shown that the cooling rate could be adjusted by changing the water flow rate, and the fracture behavior strongly depended on both the cooling rate and initial temperature. When the extreme value of cooling rate was constant, the decrease of initial temperature would lead to the increase of thermal stress, accompanied by a more serious damage of material, which was mainly because of the nonlinear relationship between thermal expansion coefficient and temperature.
研究领域:
材料科学
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工程热物理
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry B
·
2025
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IF 5.7
Yan Xiao,Meidong Lang,Xinyue Zheng,Lianlei Wen
Inspired by heat shock proteins (HSPs), thermo-sensitive coacervate-forming polycaprolactone (CPCL) was designed as natural chaperone mimics to protect proteins from thermal stress. Different from coil-globule polymers of poly(N-isopropyl acrylamide) (PNIPAM), the CPCL underwent a partial dehydration during heating, characterized as a coacervate-forming polymer. With the ability to transform between coil and coacervate state in response to temperature, this CPCL could spontaneously capture and release targeted protein, behaving like a natural chaperone of HSPs. Remarkably, compared with the PNIPAM homopolymer, the CPCL provided more efficient protection for proteins by inhibiting heat-induced aggregation above the melting temperature (Tm). Taken together, we envisioned that this CPCL with excellent biodegradability and biocompatibility could be a safe excipient for protein protection against thermal damage without separation.
研究领域:
生物材料学
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分子生物学
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生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Crystals
·
2016
·Vol. 6
·期 11
·151
·
IF 2.075
Di Wu,Han Huang,Xupeng Zhu,Yanwei He,Qiliang Xie,Xiaoliu Chen,Xiaoming Zheng,Huigao Duan,Yongli Gao
Molybdenum disulfide (MoS2) has recently attracted considerable interests due to its unique properties and potential applications. Chemical vapor deposition (CVD) method is used widely to grow large-area and high-quality MoS2single crystals. Here, we report our investigation on thermal strain-fractured (SF) single crystalline MoS2, oxidation-fractured MoS2, and normal MoS2by atomic force microscopy (AFM), Raman and photoluminescence (PL) measurements. Several new Raman modes are observed for SF-MoS2. The band gap of SF-MoS2is enlarged by 150 meV and the PL intensity is reduced substantially. These results imply that a structural transformation occurs in SF-MoS2. Our findings here are useful for the design of MoS2-based nanocatalysts with relative high catalytic activity.Keywords:thermal strain-fractured MoS2;defect;Raman spectrum;photoluminescence spectrum;structural transformation
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2022
·Vol. 33
·期 33
·25446-25462
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IF 2.779
Wang Bo-wen,Lu Jia-zheng,Gao Peng-zhao,Fu Zhi-yao,Jiang Zheng-long
In this work, the effect of Bi 2 O 3 content on the microstructure, mechanical, thermal, and electrical properties of ZnO varistors was investigated, and the high impulse current withstand properties and failure mechanism of ZnO varistors was discussed in detail. When content of Bi 2 O 3 equaled to 0.75 mol%, the varistors possessed excellent mechanical, thermal, and electrical properties, where the value of σ f and E f were 130.77 MPa and 69.60 GPa, K T and λ T were 6.504 W·(m·°C) −1 and 7.00 × 10 –6 °C −1 , E 1mA , α, J L , and K were 272.13 V·mm –1 , 55.96, 1.55 μA·cm –2 , and 1.74, respectively, being due to the highest density and finest uniform grain size distribution. Finite Element Analysis (FEA) showed that the thermal stress decreased first and then increased with the increase of Bi 2 O 3 content, where E f and λ T played a more important role than K T . And the loaded impulse current I p can generate Joule heat to improve the temperature of ZnO varistors, thereby increasing the thermal stress and promoting the migration of dopants ions from ZnO to the Bi 2 O 3 crystal lattice. Hence, J L increased and U 1mA reduced, which further increased the thermal effect generated by I p . When the value of I p equaled to 100 kA, high temperature produced a loose microstructure and broken grains originated from the strong thermal stress. Meanwhile, the enhanced migration increased J L (3.77 μA·cm −2 ) and decreased U 1mA (4.93 kV), resulting in a critical value of Δ U 1 mA (9.88%). A further increase in I p led to the failure of ZnO varistors.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Qian Qi,Wei Ji,Qiunan Li,Wanjun Li,Jinyong Zhang,Weimin Wang,Zhengyi Fu
The materials used in astronautics fields are usually designed to withstand severe thermal stress induced by large temperature differences. Compared with homogenous materials, functionally graded materials (FGM) possess gradient properties and can be applied in harsh operating conditions. In this study, ZrC–Mo multilayer FGM were designed and prepared with three gradient compositions. The as-produced ZrC–Mo FGM exhibited the dense and homogeneous morphology and excellent interlayer bonding without visible defects such as cracks and pores. The results of oxyacetylene ablation tests indicated that compared with homogeneous ZrC-based composites, the ZrC–Mo FGM could better maintain integrity and avoid catastrophic damage. An effective property transition was established by the gradient design, which could relieve the stress caused by the difference in thermal expansion coefficient between ceramic and metal materials. The FGM in the composition of quadratic function nonlinear with higher Mo content show the optimized overall performance. The study provides a new strategy for developing promising candidate materials under ultra-high temperature conditions.
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
危险品化学品经营许可证（带存储）