CORROSION SCIENCE
·
2020
·
IF 6.479
Tao Feng,Mingde Tong,Shuotian Yao,Hejun Li,Hongjiao Lin,Shifeng Wen,Peipei Wang
The B-modified SiC/HfC-SiC composites were prepared by the combination of precursor infiltration and pyrolysis (PIP) and chemical vapor deposition (CVD) methods. The microstructure, cyclic ablation and bending strength tests of the SiC/HfC-SiC composites with and without B were investigated. The results showed that the B-modified composites had a better cyclic ablation resistance than that of the composites without B. The effective residual thickness of the B-modified composites was also higher than that of the composites without B after cyclic ablation. The residual bending strength of the B-modified composites was slightly lower than that of the composites without B.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
DOI
高影响因子
HIGH PERFORMANCE POLYMERS
·
2016
·
IF 1.045
Fengyi Wang,Zhixiong Huang,Yang Liu,Yunxia Li
To improve the thermal stability of phenolic resin and develop functional sustainable adhesive, a thermal-resistant cardanol-containing boron–phenolic resin (CBPR) was prepared by copolymerizing salicyl alcohol, cardanol, and boric acid. The structure of CBPR was characterized by Fourier transform infrared spectroscopy. Thermal stability of the investigated composites was estimated using thermogravimetric analysis (TGA). The results of TGA indicated that the modified resin exhibited excellent thermal stability. Specifically, the B-0.2 thermoset had a char yield of 69% when the boron content was only 1.27 wt%. The curing kinetic behavior was well described by differential scanning calorimetry and model-free kinetic analysis. Further, CBPRs, nano-aluminum oxide powders, glass powders with low melting point, and vitreous silica fibers were used as resin matrix, filler, forming additive, and reinforced material, respectively, to produce a novel ceramizable phenolic molding composite. The ablative characteristics of the co-cured blends were explored in terms of linear/mass ablation rate and microscopic pattern of ablation via the oxyacetylene torch tests. After thermal treatment, the formation and growth of the ceramic phase enhanced the thermal stability and ablation performance of the composites at high-temperature region. The morphology and phase composition of the residual chars were studied by scanning electron microscopy and energy dispersive spectroscopy, respectively. The linear and mass ablation rates for the modified composites decreased obviously in comparison with those of the unmodified composites, indicating that the modified composites possessed enhanced thermal stability and ablation property.
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2025
·
IF 3.9
Kai Fan,Shuo Liu,Ye Ma,Qinming Wu,Sen Wang,Andree Pauschinger,Andrei-Nicolae Parvulescu,Nils Bottke,Toshiyuki Yokoi,Dirk E. De Vos,Xiangju Meng,Weiping Zhang,Feng-Shou Xiao
ITR zeolites exhibited excellent performance in methanol to propylene (MTP), where an important factor was the Al distribution of the ITR zeolites. However, optimization of the Al location in ITR zeolites in the conventional synthesis is challenging. In this work, the Al distribution in the ITR zeolites was efficiently adjusted by adding boron species in the synthesis gels due to the competitive occupancy of T sites in zeolites between boron and aluminum species. The obtained ITR with different boron content zeolites displayed similar nanosheet morphology, textural parameters, and strong acidic concentration but characterizations of Al distribution showed that the addition of boron species led to more Al species distributed in a relatively small sinusoidal channel and less Al species located in an intersection cavity. As a result, the aromatic cycle would be effectively suppressed due to the steric configuration of large aromatic cycle intermediates, whereas the alkene cycle will be enhanced correspondingly. As expected, catalytic tests in the conversion of MTP showed that the new ITR zeolites exhibited enhanced propylene selectivity and catalyst lifetime with the incorporation of boron species, which was attributed to different Al distribution in these ITR zeolites.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
ChemCatChem
·
2022
·Vol. 14
·期 13
·e202200311
·
IF 5.497
Yuyao Zeng,Bowei Wang,Fanyong Yan,Wensheng Xu,Guoyi Bai,Yang Li,Xilong Yan,Ligong Chen
Graphical Through a convenient impregnation method, highly-distributed and stable Cu nanoparticles were dispersed on the boron doped γ-Al 2 O 3 support, which catalyzed continuous reductive amination of levulinic acid to corresponding N-substituted pyrrolidinones. The reductive amination of biomass-derived levulinic acid (LA) to value-added N-substituted pyrrolidinones with amine and molecular hydrogen over heterogeneous catalyst represents an atom-economical and scalable route. In this paper, a series of boron doped Cu/Al 2 O 3 catalysts via kneading and impregnation method are developed for the continuous reductive amination of LA. Compared with Cu/Al 2 O 3 , Cu 10 /AlB 3 O catalyst exhibits greatly improved catalytic performance for this reaction at low operation temperature. Structure-property correlation investigations were performed with diverse characterization methods, and the results revealed that the excellent catalytic performance of boron doped Cu/Al 2 O 3 catalysts was mainly attributed to the synergistic effect of its well-dispersed Cu nanoparticles, appropriate surface Cu electronic state and surface acidic sites nearby. Besides, Cu 10 /AlB 3 O shows great stability during the reaction over 200 h. This work provides a low-cost, efficient and environmentally friendly heterogeneous catalytic system for the continuous production of N-substituted pyrrolidinones.
研究领域:
催化化学
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绿色化学
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生物质转化
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Junguo Li,Chenhan Zhao,Feng Jiang,Shiquan Zhang,Suohui Yang,Qianqian Xiang,Meijuan Li,Jian zhang,Qiang Shen
Ceramizable carbon fiber/boron-modified phenolic resin (C f /BPR) composites are cost-effective and suitable for fabricating large-scale components, making them vital for thermal protection systems in aerospace vehicles. However, their thermal resistance requires further improvement. This study investigates the modification of C f /BPR composites using ZrSi 2 , Al, and mica to enhance their thermal resistance. High-temperature static oxidation and oxyacetylene ablation tests are conducted to evaluate their high-temperature performance. The role of each filler on oxidation resistance is discussed. The results reveal that when ZrSi 2 is added at 33.75 phr, Al at 3.75 phr, and mica at 5 phr, the prepared composite exhibits a flexural strength of 56 MPa after 20 min of static oxidation at 1600 °C, with excellent protection of the carbon fibers. After oxidation at 1670 °C, the flexural strength remains at 45 MPa, despite some degree of carbon fiber ablation.
研究领域:
航空航天材料
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Jichao Liang,Bowen Liu,Jinchao Lu,Yanliang Zhu,Yang An,Danyang Liu,Xin Lu
This study aims to put forward new insights into preparing high-performance titanium (Ti) materials by selective laser melting (SLM). Employing low-cost modified TiB 2 /Ti composite powder suitable for the SLM process as raw materials, boron modified titanium materials with high relative density (99.86 %), no cracking, and excellent comprehensive properties were successfully fabricated. A systematic analysis was carried out on the evolution of the matrix microstructure induced by TiB whiskers, and the strengthening mechanism of boron modified titanium materials was deliberated. During the SLM process, TiB 2 undergoes a complete in-situ reaction with the Ti matrix, precipitating nanoscale TiB whiskers with an average length of 102.0 nm, a width of 17.2 nm, and a content of 0.71 wt%. The heterogeneous nucleation and pinning effects induced by TiB whiskers result in significant refinement of grains, with the average size of titanium grains attaining 3.3 μm. After heat treatment (750 °C/2 h), the aspect ratio of TiB whiskers increases significantly (∼19.4). The room temperature ultimate tensile strength (UTS) of the boron modified titanium materials is 1103 ± 12 MPa, with an elongation (EL) of 3.9 ± 0.5 %. Following heat treatment, the room temperature UTS of the material is 995 ± 11 MPa, and the EL is 8.0 ± 0.6 %. The strengthening mechanisms introduced by TiB before and after heat treatment primarily depend on the contributions of dispersion strengthening and grain refinement strengthening, followed by solid solution strengthening and TiB load-bearing strengthening. The synergistic effect of these four mechanisms contributes to the tensile properties of boron-modified titanium materials. The results show that the size of TiB whiskers and the degree of grain refinement play a crucial role in enhancing the performance.
研究领域:
材料科学
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金属加工
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复合材料制备
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产品关联
DOI
高影响因子
MATERIALS RESEARCH INNOVATIONS
·
2015
·
IF 0.83
J. Ding,Z. Huang,H. Luo,Y. Qin,M. Shi
A polymer matrix composite was prepared by incorporating microcrystalline muscovite fillers into a boron-modified phenolic resin. Thermogravimetric analyses indicated that microcrystalline muscovite significantly enhanced the thermal stability of boron-modified phenolic resin under air atmosphere. Then the composite was heated in a furnace. After heated, the homogeneous structure of the composite was converted into a layered structure with a ceramic shell on the surface. The layered structure was investigated by electron probe micro-analysis and energy dispersive spectroscopy. The elemental content and chemical binding state of the layered structure were investigated by X-ray photoelectron spectroscopy. On the surface, the reaction between SiO2 and Al2O3 occurred, thus microcrystalline muscovite fillers were transformed into mullite shell. The mullite shell could protect char from further oxidation at elevated temperatures. Therefore, a amount of reserved char could react with SiO2 to generate Si–C bond in the inner of the composite.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Chaoqun Zhu,Lukun Feng,Binbin Xu,Qingying Lin,Xiaoli Cheng,Jiangxi Chen,Guomei He
SiC–TiB 2 ceramic nanocomposites are valuable ultra-high temperature materials, which are rarely prepared from preceramic polymers. In this work, we synthesized SiC–TiB 2 nanocomposites from a new preceramic polymer called titanium- and boron-modified polycarbosilane ( TB–PCS ). The polymer structure was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. The structure, composition, and morphology of the resulting ceramic products were investigated by FT-IR, X-ray diffraction, and transmission electron microscopy . The elements of titanium and boron were incorporated into the preceramic polymer, and nanoscale TiB 2 and β-SiC grains generated in situ were detected in the pyrolyzed ceramic products at temperatures higher than 1400 °C. The new preceramic polymer presents a novel approach to preparing SiC–TiB 2 nanocomposites.
研究领域:
材料科学
·
陶瓷材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2024
·Vol. 59
·期 19
·8556-8570
·
IF 3.5
Wang Jianwen,Huang Siyu,Shi Fengyue,Yang Yang,Yang Xinjia,Li Jun,Zhao Guangdong
The synthesis of Bisphenol A Glutaraldehyde Phenolic Resin (BPA-GA PF) was carried out under alkaline conditions using Bisphenol, A (BPA) and Glutaraldehyde (GA) as raw materials, with n-butanol serving as the solvent. Based on the aforementioned information, the researchers prepared modified BPA-GA PF resins by incorporating titanium (Ti), silicon (Si), and boron (B) through a polymer derivative method. This process led to the formation of Ti/Si/B-modified PF resins. By manipulating the proportion of elements in the BPA-GA PF, the modified phenolic resin demonstrated improved capacity for design and processing. The characterization of the modified BPA-GA PF involved the analysis of its transformation process and thermal behavior through the utilization of Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric Analysis (TGA). The presence of B, Ti, and Si elements in the system resulted in the formation of Si–O-B and B-O bonds, as determined. The Ti/Si/B -modified PF exhibited a significant increase in yield. Analysis employing X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) revealed that, following high-temperature annealing, the materials underwent a transformation into Ti/Si/B-modified PF with a highly cross-linked network structure. Oxidation experiments conducted under static conditions demonstrated that the Ti/Si/B-modified BPA-GA PF exhibited significantly greater high-temperature resistance compared to the BPA-GA PF. Among the various options, the Ti/Si/B-modified PF material with a Ti/Si ratio of 1:2 exhibited the most superior resistance to high-temperatures.
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 APPLIED POLYMER SCIENCE
·
2025
·
IF 2.8
Hongbao Wang,Zonglin Yi,Hao Liu,Zhenbo Zhao,Shouchun Zhang,Quangui Guo,Fangyuan Su,Xinghua Zhang
The boric acid modification offers an effective approach to improve the radial homogeneity and mechanical performance of polyacrylonitrile (PAN)-based carbon fibers by affecting stabilization behavior. However, the mechanism of how boron affects the stabilization process remains unclear. Herein, the impact of boron on the cyclization and oxidation reactions is investigated through experimental data and computational calculations. The results reveal that boron oxide exhibits a stronger electron-withdrawing effect on cyano nitrogen compared to hydroxyl oxygen, effectively inhibiting both ionic and free radical cyclization reactions, as well as subsequent oxidation reactions in the skin regions. This inhibitory effect enhances the cross-sectional oxygen uptake and stabilization. The boric acid also improves the preferred orientation in precursor fibers by reducing the polarity of cyano groups and promotes the inheritance of structural characteristics from precursor fibers through “cross-linking” effect. Consequently, the structural characteristics and mechanical properties of modified carbon fibers are significantly improved. These findings could provide fundamental insights into the mechanisms of thermal reaction regulation and microstructure evolution in the preparation of high-performance PAN-based carbon fibers.
研究领域:
材料科学
·
高分子科学
·
化学工程
·
纳米技术
·
机械工程
✓ 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）