CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2025
·
IF 3.7
Tingting Ma,Junjian Xie,Hui Li,Kaixin Wei,Zhibin Xu,Zihui Meng,Xiu-Tian-feng E
Fluorine-containing compounds have proven to be effective coating materials for enhancing the combustion efficiency of aluminum micro-particles (Al MPs). However, these compounds are usually low-energy polymeric materials, which may inevitably diminish the overall energy density of propellants or explosives. This study introduces a two-step coating strategy using fluorinated energetic small-molecule 2-NCF to coat Al MPs, employing FeCl 3 as an intermediate layer. Compared to pristine Al MPs, 2-NCF coated Al MPs can reduce the ignition delay from 36 ms to 3 ms and shorten the time to maximum flame area from 551 ms to 114 ms, accompanied by intensified sparking combustion. Thermal analyses demonstrate that the energetic 2-NCF induces localized micro-explosions to disrupt the alumina shell, and the fluorinated segments produced by 2-NCF react with the aluminum, followed by β -AlF 3 to α -AlF 3 phase evolution, which sustains oxygen penetration for complete aluminum core oxidation to release more energy. The 2-NCF coating concurrently enhances hydrophobicity of Al MPs, elevating contact angles from 0° to 120°. This coating can effectively block water penetration and prevent hydrolysis of the inner aluminum during long storage. This work demonstrates the potential of 2-NCF as an excellent high-energetic coating material to enhance the combustion and hydrophobic performance of aluminum powder.
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SOLAR ENERGY MATERIALS AND SOLAR CELLS
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2025
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IF 6.3
Shuhui Chen,Jinjie Mo,Ziye Ling,Zhengguo Zhang,Xiaoming Fang
The propensity for leaks in high-temperature molten alloys greatly restricts their extensive use in storing high-temperature thermal energy. In tackling this matter, the research concentrates on Al-Si/AlN composite phase change materials (PCMs), incorporating the modifier Sb to significantly improve their heat conduction and thermal steadiness. The results reveal that incorporating Sb alters the Si phase from a bulk form to an elongated one, simultaneously triggering the creation of an Al-Si@Al 2 O 3 core-shell configuration. This structural optimization reduces free electron scattering and extends the mean free path of electrons, thereby improving the thermal conductivity of the material. It was established that the ideal fraction of Sb mass is 0.6 %, where the thermal conductivity of the Sb-altered Al-Si/AlN composite PCMs attains 49.5 W/(m·K), marking a 15.2 % enhancement over the original Al-Si/AlN composite PCMs, with a latent heat of 351.5 kJ/kg. Additionally, the creation of the Al 2 O 3 shell led to the altered materials showing remarkable thermal stability across 200 high-temperature thermal cycles, resulting in less than a 4 % decrease in latent heat post-cycle and no leakage detected. The study offers not just an innovative approach for creating advanced Al-Si/AlN composite PCMs but also broadens their use in storing thermal energy at high temperatures.
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INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
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2025
·
IF 4.6
Taotao Cai,Ying Zhang,Shili Zheng,Longkai Liu,Yi Zhang,Bin Yu
V Al master alloys are essential raw materials for producing high-quality titanium alloys, which are generally produced by aluminothermic reduction, metal-slag gravitational separation method. The conventional way faces the challenges of excessively high reaction temperatures, metallic inclusions in slag, and difficulties in fabricating higher-Al-content alloy in one step. To conquer these issues, this research has reported a new method to precisely fabricate V Al master alloy with a designated composition, which is an aluminum reduction coupled with an acid leaching process. The reduction byproduct of weak-acid-soluble calcium aluminate, the critical parameters for Al reduction, and the reaction routes are determined. This research has demonstrated that various V Al master alloys (expressed as AlV x ) are successfully prepared by heating the optimal mixture of V 2 O 3 + (2 + 2 x -)/ x Al + 2.0CaO + 1.35CaCl 2 (in molar ratio) at 1000 °C for 5 h in Ar and pickling the reduction material using HCl acid with pH controlled at 1.2. Oxygen in 6Al4V, 4Al6V, and 2Al8V alloy powders are 400 ppm, 500–700 ppm, and 1800–2000 ppm, respectively. The 4Al6V powder produced by this reported method is compared with the commercial one, with comparable phase and chemical compositions but with finer sizes preferred in powder metallurgy sintering. The main reactions or phase changes that happen during heating include stepwise removal of surface and crystalline water from CaCl 2 , melting of Al, reaction between V 2 O 3 and CaO, melting of CaO-CaCl 2 binary compound, and Al reduction reaction. The method developed in this study can also be used to prepare other alloys, such as Ti Al and Ti Fe alloy powders.
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APPLIED SURFACE SCIENCE
·
2025
·
IF 6.9
Jianxiang Lin,Shaoping Chen,Zhenyang Qi,Wenhao Fan,Qiang Zhang,Tao Zhang,Zhiyi Zhang,Qingsen Meng
Significant physicochemical differences between metals and thermoplastics pose challenges for achieving strong interfacial bonding under conventional forming processes. This work presents a novel approach using an external electric field (EEF) to activate functional groups at metal-polymer interfaces, forming complex chemical bonds and strong heterogeneous connections. Silane-modified PA66 composites filled with high-content aluminum spheres were fabricated. Experimental results show that the chemical bonding between Al and PA66 under EEF is due to extensive functional group reactions and secondary bonding within Al-PA66 interface, achieving a remarkable ultimate tensile strength of 65 MPa for the composite with 50 wt% Al filling. Moreover, dissimilar joints of composites and 6061T6, made by friction stir welding, exhibit high strength due to the formation of a “Novel Net-Metallurgy Bonding Structure” during frictional heat transfer. This work provides new insights and theoretical guidance for interfacial bonding in metal-polymer heterogeneous interfaces.
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Chinese Physics B
·
2025
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IF 1.5
Wenxia Zhang,Weixia Shen,Chao Fang,Ye Wang,Yuewen Zhang,Liangchao Chen,Qianqian Wang,Kenan Li,Biao Wan,Zhuangfei Zhang
Improving the thermal conductivity of diamond-metal composites has always been a significant challenge in the field of thermal management. In this paper, diamond/Al composites were systematically studied, and the influence of holding time (10-120 min) on interface structure and thermal conductivity was discussed. The research results shows that the long-term thermal diffusion sintering can effectively the dense interfacial bonding of diamond/Al composites and enhance the thermal conductivity. The diamond/Al composites with 50 vol% 900 μm diamond attained the highest value of 888.73 W/mK under the sintering conditions of 650 ℃, 50 MPa, and 120 min, nearly 92% of the theoretical value predicted by the Maxwell model. This study establishes that high thermal conductivity can be achieved through long-term thermal diffusion alone, without the complex diamond surface coating and substrate alloying.
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Journal of Energetic Materials
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2025
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IF 1.9
Xueqian Wan,Jiaming Gao,Fuding Sun,Chongchong She,Jingbo Li,Baolong Fan,Kun Chen
Aluminum readily undergoes oxidation under ambient conditions, forming a dense Al2O3 surface layer that retards the energy release by oxidation. To enhance the energy release of aluminum powder oxidation, this study focused on the preparation of liquid metal (LM) mediated thermite (LM-Al@oxide) by combining the aluminum powder with the nanosized metal oxides. The thermal properties of thermite and its catalytic effects on the thermal decomposition of dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) were investigated by differential scanning calorimetry (DSC). Specifically, WO3 and Fe2O3 significantly reduced the onset oxidation temperature of aluminum to near its melting point. Upon incorporating LM-Al@oxide composites, both the peak decomposition temperature and activation energy of TKX-50 decreased. Among them, LM-Al@Fe2O3 exhibited optimal catalytic activity for TKX-50 decomposition, reducing its peak decomposition temperature (Tp1) and mean apparent activation energy (Ea) by 24.5°C and 59.0 kJ·mol−1, respectively, which could be attributed to electron acceptance from TKX-50 through Lewis acid sites in the oxides, thereby lowering the decomposition energy barrier.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2025
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IF 6.3
Peibo Li,Guoqiang Luo,Guinan Zhao,Huawu Liu,Yi Sun,Qiang Shen
Al powder is prone to oxidation, which can introduce impurities in powder metallurgy. In this study, Al 2 O 3 nanonetworks were obtained by destroying the oxide layer through Paulse Activated Sintering (PAS). The network and the nano-precipitation enhance the mechanical properties of Al-Cu-O composites. TEM analysis revealed the formation of CuAl 2 and an Al 2 O 3 network at the grain boundaries. The current facilitated the modulation of the intermetallic compound size and the fragmentation of the oxide layer. The current-induced discharge at the particle interfaces generated localized heating. Higher temperature effectively disrupts the oxide layer. The Al 2 O 3 network improved the fracture toughness of the Al-Cu-O composites by passivating crack propagation. Simultaneously, the current reduced the nucleation barrier for precipitation by promoting directional atomic migration. Uniformly dispersed nano-precipitates are conducive to the improvement of strength. This study provides new insights into oxidation-related challenges in Al powder.
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PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
·
2025
·Vol. 222
·期 22
·2500553
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IF 1.9
Yaqi He,Xinhua Li,Lihua Zhang,Jiawei Xu,Songhua Chen,Zongqing Ma
In this article, a batch of high-performance Sn-doped Nb 3 Al superconductors is prepared through mechanical alloying and subsequent low-temperature sintering. This article comparatively analyzes the superconducting properties, phase structure, and microstructure of Sn-doped Nb 3 Al under different sintering temperatures and sintering times to determine the most suitable sintering process for Sn-doped Nb 3 Al. The results show that the optimum sintering temperature of Sn-doped Nb 3 Al bulks is 800 °C, with an optimal sintering time of 5 h. The T c value of Sn-doped Nb 3 Al bulk obtained under this sintering condition is 14.8 k, and the value of J c is as high as 6.2 × 10 4 A cm −2 (4.2 K, 5 T). The elevated sintering temperature (900 and 1000 °C) results in significant growth of both Nb 3 Al grain size and Nb 2 Al nanoparticles. This reduces the number of effective pinning centers in the superconducting phase of Sn-doped Nb 3 Al, which severely weakens the flux pinning effect. As a result, the J c performance deteriorates gradually as the sintering temperature increases from 800 to 1000 °C. The extended duration of sintering time results in the formation of sintering holes, which significantly disrupt the continuity of the Nb 3 Al superconducting phase matrix and degrade its superconducting properties.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
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IF 6.3
Yaqi He,Xinhua Li,Zhu Qian,ZuPeng Yan,Guizhen Shi,Xia Sun,Zongqing Ma
In this paper, we innovatively introduced Sn and B into the Nb-Al system at the same time and successfully prepared high-performance Nb 3 Al bulks through mechanical alloying and subsequent low-temperature sintering processes. The influence of different doping amounts of B in the Sn-B co-doping on the superconducting properties of Nb 3 Al superconductors was also investigated. It was found that Sn-B co-doping greatly improves the superconducting properties of Nb 3 Al, especially the J c properties, compared with the undoped sample. The optimal doping amount of Sn-B co-doping is finally determined to be 4 at% Sn-2.6 at% B. At this time, the superconducting transition temperature of Nb 3 Al is up to 16.2 K, and the critical current density reaches up to 1.3 × 10 5 A⋅cm −2 (4.2 K, 5 T), which is almost twice higher than that of Sn-doped Nb 3 Al, and one order of magnitude higher than that of general undoped Nb 3 Al. Combined with the phase composition analysis and microstructure observation, we find that with the co-doping of Sn and B, the grain size of Nb 3 Al is refined, and the diffusely distributed Nb 2 Al nanoparticles are introduced, which greatly enhance the magnetic flux pinning effect of Nb 3 Al. Secondly, the intergranular connectivity of Nb 3 Al is significantly improved. The Sn-B co-doped Nb 3 Al superconductors combine the advantages of Sn doping to enhance flux pinning and B doping to improve intergranular connectivity, which synergistically promotes the dramatic improvement of Nb 3 Al superconductivity Nb 3 Al.
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