微晶纤维素基复合材料的制备及其对亚甲基蓝的催化降解性能

以微晶纤维素(MCC)为原料,通过在其表面负载纳米氧化铜颗粒(CuO NPs),添加3-氯丙基三甲氧基硅烷(CPTES)与二乙醇胺(DEA)进行接枝反应制备CuO NPs@MCC–Si–N(OH)₂复合材料。探讨了DEA添加量对CuO NPs@MCC–Si–N(OH)₂性能的影响,表征并分析了改性微晶纤维素红外光谱、晶体结构、表面形貌和热稳定性。结果表明,CuO NPs可成功负载在MCC表面,硅烷偶联剂可提高复合材料的分散性与接枝胺基的能力,进而增强其催化活性,使硼氢化钠(NaBH₄)与亚甲基蓝(MB)氧化还原反应效率增加,快速降解MB染色剂。通过优化发现DEA用量为20wt%时制得的CuO NPs@MCC–Si–N(OH)₂催化效果最佳,CuO NPs@MCC–Si–N(OH)₂和NaBH₄的用量分别为30 mg和10 mg,处理30 mL 3 mmol/L MB溶液5 min后,MB去除率可达99.71%,五次循环性测试后,去除率为93.24%。      

Al（OH）3和Cl一对稀土铝热浸镀层腐蚀行为的影响

以自制热浸镀稀土铝为研究对象,采用失重法、极化曲线、SEM和电化学阻抗测试研究了淡水中存在的A1（OH）3对镀层腐蚀行为的影响;同时,通过极化曲线考察了饱和A1（oH）3溶液中C1一浓度对镀层腐蚀的影响。结果表明：A1（OH）3能够抑制镀层破损钝化膜的修复,促进阳极活化,诱导镀层点蚀反应的发生,使腐蚀加剧;随Cl一浓度...     

Zn掺杂CuO/CuAl2O4复合空心球的制备及光催化性能

以葡萄糖为模板, 硝酸锌、硝酸铜和硝酸铝为原料, 采用水热法制备高比表面Zn-CuO/CuAl₂O₄复合空心球。采用XRD、SEM、HRTEM、BET、DRS和PL等手段对样品进行表征, 结果表明: 在600℃下焙烧的Zn-CuO/CuAl₂O₄复合物呈空心球状, 球体直径约为2 μm, 比表面积高达214.97 m²/g。引入Zn有助于提高样品对紫外和可见光的吸收能力, 减少光生电子空穴对的复合, 光催化活性显著提高。在模拟太阳光照下, 以甲基橙溶液为目标降解物, 考察样品的煅烧温度和Zn加入量对光催化活性的影响。当Zn加入量为0.5wt%, 煅烧温度为600℃时, 样品的光催化活性最佳。光照60 min, 0.5 g/L光催化剂用量对25 mg/L甲基橙溶液的脱色率高达97%。     

苯甲酸功能化石墨烯-Al(OH)3协同阻燃聚丙烯

以氧化石墨（GO）为原料,制备了苯甲酸功能化石墨烯（BFG）,采用IR和XRD对BFG结构进行了表征。再将BFG作为阻燃协效剂添加到Al（OH）₃/聚丙烯（PP）中,研究不同质量比的BFG与Al（OH）₃对PP材料阻燃和力学性能的影响。通过对阻燃BFG-Al（OH）₃/PP复合材料进行极限氧指数（LOI）测试、热失重分析、锥形量热分析、拉伸测试及残炭SEM分析,考察BFG-Al（OH）₃/PP复合材料的阻燃性能和力学性能。研究结果表明,与其他阻燃PP相比,1.5wt% BFG-38.5wt% Al（OH）₃/PP的阻燃和力学性能最佳,LOI可达到24.6%,拉伸强度为20.64 MPa,且其热释放速率峰值和总热释放量比纯PP分别降低了51.5%和18.6%。     

Al(H2PO2)3/聚氨酯弹性体复合材料的制备及阻燃性能

采用熔融共混技术,将Al（H₂PO₂）₃引入聚氨酯热塑性弹性体,制备了一系列次磷酸铝/聚氨酯弹性体复合材料（Al（H₂PO₂）₃/TPU）。采用极限氧指数（LOI）、垂直燃烧（UL-94）、锥形量热测试、TG和SEM研究了Al（H₂PO₂）₃对Al（H₂PO₂）₃/TPU复合材料阻燃性能及热稳定性的影响,采用力学测试研究Al（H₂PO₂）₃对其力学性能的影响。阻燃测试表明,Al（H₂PO₂）₃可以有效提高Al（H₂PO₂）₃/TPU复合材料的阻燃性能。当Al（H₂PO₂）₃添加量为20wt%时,Al（H₂PO₂）₃/TPU复合材料UL-94级别达到V-0级,LOI达到30.5vol%。热重测试表明,Al（H₂PO₂）₃的加入会导致复合材料热分解温度降低,但其残炭率有明显升高。锥形量热测试表明,Al（H₂PO₂）₃的加入有效降低复合材料热释放速率峰值（pHRR）和总热释放（THR）,并明显提高其火灾安全性能,其中20wt% Al（H₂PO₂）₃/TPU的pHRR和THR相对纯TPU分别下降65.7%和20.2%。SEM表明,Al（H₂PO₂）₃/TPU复合材料炭渣致密性有明显提高。在此基础上,采用TGA-FTIR联用分析Al（H₂PO₂）₃/TPU复合材料阻燃机制,研究发现,Al（H₂PO₂）₃在燃烧过程中可以有效促进TPU裂解产物成炭,降低可燃性气体生成量,从而提高复合材料阻燃性能。     

复合催化材料纳米氧化铜颗粒(CuO NPs)@纤维素纳米纤丝(CNF)-Si-N(OH)2的制备及其对4-硝基苯酚的催化还原性能

针对目前降解工业废水中4-硝基苯酚(4-NP)的催化剂效率低,催化活性差等问题,以桉木漂白化学浆为原料,通过超微粒研磨机和高压均质机处理制备得到直径50～100 nm和长度1 500～2 000 nm的纤维素纳米纤丝(CNF),在其表面原位负载纳米氧化铜颗粒(CuO NPs),并通过3-氯丙基三甲氧基硅烷(CPTES)与二乙醇胺(DEA)进行接枝反应制备得到复合催化材料-CuO NPs@CNF-Si-N(OH)2。探讨了DEA添加量对CuO NPs@CNF–Si–N(OH)₂的性能影响,采用Zeta电位、FTIR、XRD、XPS、热重分析和形貌分析等方法对复合材料进行了表征。结果表明,CuO NPs被原位还原并成功负载在CNF表面,其直径约为3.84 nm,负载量为3.83wt%,通过硅烷化改性及接枝胺基可提高CuO NPs在复合材料表面的分散性及稳定性,进而增强了其催化活性。CNF基复合催化材料对4-NP的催化还原结果显示,DEA添加量为20wt%下的CuO NPs@CNF-SiN(OH)₂对4-NP催化还原性能最佳,在180 s内可催化还...     

Electro/EIectrolless Deposited Alloy Based Solar Selective Absorber Coatings

The chemical composition, morphology, selective absorber characteristics and degradation of selective absorber characteristics at high temperatures of black chrome solar selective coating are influenced by various substrate pre-treatments like mechanical polishing, chemical etching and electropolishing prior to film deposition. The major oxide content in the deposit is formed as Cu₂(OH) ₂CrO₄(JCPDS 38-0230), which on high temperature annealing decomposes to CuCrO₄(JCPDS 34-0507), CuO (JCPDS 41-0254) and Cu₂O (JCPDS 5-0667). Formation of the oxides of Cu at high temperatures retains the high optical absorption characteristics of the coating even after high temperature degradation.     

Microstructure and formation of copper oxide in the Cu electro-polishing process

In this study, the formation of Cu oxide on Cu film is studied during Cu electropolishing in a phosphoric acid-based electrolyte with various Cu ion concentrations, from 2.28% to 10.08%. In cyclic voltammetry measurement, the maximum current density of the anodic peak (Imax) decreases from 38.87 to 28.13 mA/cm2 with increasing Cu ion concentration, indicating that an oxide film forms on the Cu film surface and the thickness increases with Cu ion concentration. Microstructures and crystallography of the oxide film are examined by transmission electron microscopy, which confirms the increase of the oxide film thickness due to the high Cu ion concentration in a H3PO4 electrolyte. Three types of Cu oxide are detected using X-ray photoelectron spectroscopy, namely Cu2O, Cu(OH)2, and CuO. With a Cu-ion electrolyte concentration of less than 6.99%, Cu(OH)2 is dominant, while at higher Cu-ion concentrations, CuO predominates. The formation of CuO protects Cu from corrosion in the electrolyte with the Cu-ion concentration of over 6.99%.     

无机填料对环氧模塑料导热和阻燃性能的影响

采用两种无机填料Si₃N₄和Al(OH)₃ 复合填充环氧树脂制备了环氧模塑料(EMCs), 研究了两种填料用量及单独添加和复合添加对环氧模塑料导热性能和阻燃性能的影响。研究结果表明, 单独添加Si₃N₄或Al(OH)₃对环氧模塑料导热性能和阻燃性能的影响规律基本一致, 即随着填料含量的增加, 环氧模塑料的导热性能和阻燃性能均有不同程度的提高; 复合添加Si₃N₄和Al(OH)₃对环氧模塑料的导热性能和阻燃性能均起到积极作用, 但是随着填料中Si₃N₄与Al(OH)₃体积比的变化, 材料导热性能与阻燃性能会产生交叉耦合作用。当 填料中Si₃N₄与Al(OH)₃体积比为3∶2, 总体积分数为60%时, 环氧模塑料的导热率可以达到2.15 W/(m·K), 氧指数为53.5%, 垂直燃烧达到UL-94 V-0级。      

环交联聚磷腈包覆羟基锡酸锶杂化纳米棒的合成及阻燃环氧树脂研究

为了开发新型无机-有机杂化的阻燃消烟剂, 本研究采用共沉淀法合成了棒状纳米羟基锡酸锶(SrSn(OH)₆), 并用环交联聚磷腈(PZS)对其进行包覆, 得到一种核壳结构的有机无机杂化纳米阻燃剂(PZS@SrSn(OH)₆)。通过扫描电镜、透射电镜和红外光谱研究了PZS@SrSn(OH)₆的微观形貌和化学结构。通过热重分析研究了PZS@SrSn(OH)₆及EP/PZS@SrSn(OH)₆阻燃复合材料的热降解行为。采用极限氧指数和锥形量热对复合材料阻燃性能进行测试, 用X射线衍射、扫描电镜、能谱分析及红外光谱对EP/PZS@SrSn(OH)₆的阻燃机理进行分析。结果表明PZS@SrSn(OH)₆在环氧树脂中展现出高阻燃效率和抑烟效果, 且PZS与SrSn(OH)₆之间存在显著的协同阻燃效应。与纯环氧树脂相比, 仅添加3wt%的PZS@SrSn(OH)₆时, 极限氧指数(LOI)值从26.2%增加到29.6%。锥形量热结果表明热释放速率峰值降低了约29%, 烟释放速率峰值降低了约37%, 残炭率提高了242%。PZS@SrSn(OH)₆在高温下形成致密结构炭层, 隔绝分解产物及热量和氧气交换, 从而显著提高环氧树脂的阻燃效果。     

微胶囊Mg (OH)2的合成及其对乙烯-乙酸乙烯酯共聚物的阻燃作用

用原位聚合方法合成了以微米Mg（OH）₂粒子为芯材、交联聚脲为壁材的微胶囊Mg（OH）₂（M-Mg（OH）₂）阻燃剂,并把M-Mg（OH）₂加入到乙烯-乙酸乙烯酯共聚物（EVA）中,研究了M-Mg（OH）₂对EVA的阻燃作用。采用FTIR、SEM、热分析和酸滴定方法研究了M-Mg（OH）₂的性质,用极限氧指数（LOI）和垂直燃烧方法（UL-94）研究了M-Mg（OH）₂/EVA复合材料的阻燃性能以及酸腐蚀对M-Mg（OH）₂/EVA复合材料阻燃性能的影响。结果表明,采用原位聚合方法能够成功地在Mg（OH）₂粒子表面包覆交联聚脲壁材,得到M-Mg（OH）₂。与纯Mg（OH）₂相比,M-Mg（OH）₂的颗粒尺寸增大,热稳定性增加,在水中溶解度显著降低,在EVA基体中分散更加均匀。阻燃剂用量相同时,M-Mg（OH）₂/EVA复合材料的LOI总是比Mg（OH）₂/EVA复合材料的数值稍大。阻燃剂与EVA质量比小于135∶100时,两种复合材料的垂直燃烧级别均为V-2级,阻燃剂与EVA质量比在135∶100~150∶100之间时,前者的燃烧级别为V-0级,而后者只能达到V-2级,阻燃剂与EVA质量比超过150∶100时,两种复合材料都能达到V-0级。M-Mg（OH）₂/EVA复合材料的耐酸性比Mg（OH）₂/EVA大幅度提高,可以在酸性环境中使用。     

Characterization of Cat-CVD grown Si–C and Si–C–O dielectric films for ULSI applications

Si–C films with the Si compositions ranging from 40 to 70% have been grown by Cat-CVD using dimethylsilane [DMSi, Si(CH₃)₂H₂] compounds. Tetraethoxysilane [TEOS, Si(OC₂H₅)₄] and dimethyldimethoxysilane [DMDMOS, Si(CH₃)₂(OCH₃)₂] gas source gave us Si–C–O (C-doped SiO_x) films with wide ternary alloy compositions. The dielectric constant of a Si–C film has been evaluated by C–V measurements (at 1 MHz) using Al/Si–C/n-Si(001)/Cu MIS structure. The relative dielectric constant value of a Si–C film was estimated to be 3.0. The resistivity of the Si–C layer with 1 mm diameter and 0.24 μm thickness was estimated to be more than 24.5 Gohm·cm. These results gave us promising characteristics of Si–C and Si–C–O films grown by alkylsilane- and alcoxysilane-based Cat-CVD.     

Effect of powder processing and alloying additions (Al/ZrB2) on the microstructure,mechanical and electrical properties of Cu

The present work elucidates the effect of powder processing conditions (milling/mixing) and conductive alloying element (Al: aluminium) and ceramic (ZrB₂: zirconium diboride) reinforcement addition on the densification, microstructure and electrical conductivity of copper (Cu) processed via hot pressing route. Disregard of alloying element/reinforcement/content or powders preparation method, the density of Cu materials varied between 92.16 and 99.76% ρ_th (theoretical density) after hot pressing at a low temperature of 500 °C. In case of Cu-Al alloys, the powder processing method significantly influenced its microstructure and conductivity. Particularly the Cu-Al alloys processed using mixed powders consisted of various phases Cu, α-Cu, γ₁ (Cu₉Al₄), δ (Cu₃Al₂), ζ₁ (Cu₄Al₃), η₂ (CuAl) and θ (CuAl₂) and the Cu alloys prepared using milled powders composed of either only α-Cu or α-Cu and γ₁ (Cu₉Al₄) phases (depending on the Al content). Whereas, only Cu and ZrB₂ phases were observed with the Cu-ZrB₂ composites processed using either milled or mixed powers. In case of Cu-Al alloys, the hardness (0.88–3.41 GPa) and strength (540.30–1120.18 MPa) of Cu increased with the addition of Al. Interestingly, the hardness (0.88–2.55 GPa) and strength (508.50–970.60 MPa) of Cu increased upto 5 wt% ZrB₂ and then they lowered with further addition of ZrB₂. In particular, the hardness and strength of Cu-ZrB₂ composites are lower than Cu-Al alloys reflecting the effectiveness of solid solution strengthening in the Cu alloys as compared to dispersion strengthening mechanism in Cu composite. The pure Cu prepared using milled powders exhibited low conductivity (75.70% IACS) than Cu processed using as-received/un-milled powders (97.00% IACS). Also, the Cu-ZrB₂ composites measured with better electrical conductivity than Cu-Al alloys. Depending on the milling conditions and alloying/reinforcement amount, the conductivity of Cu-ZrB₂ composites varied between 44.10 and 88.70% IACS.     

Influence of Si content on microstructure of TiAl alloys

A systematic study of four ternary TiAl-based alloys with constant Ti content of 52.2at.% and variable Si content ranging from 0.3 to 2.7at.% (Al in balance) was conducted. The alloys were prepared from elemental powders via a route including powder mixing, precompaction, cold extrusion, and reactive hot-isostatic pressing. All investigated alloys contain the intermetallic compounds γ-TiAl, ₂-Ti₃Al, and ζ-Ti₅(Si,Al)₃. The microstructure can be described as a duplex structure (i.e., lamella γ/₂ regions distributed in a γ matrix) containing ζ precipitates. With increasing Si content, the number of primary ζ precipitates increased and the γ grain size became finer while the lamellar volume fraction decreased slightly.     

Synthesis of Bulk Nano-Al2O3 Dispersed Cu-Matrix Composite Using Ball Milled Precursor

Kinetics of solid-state reduction reaction during ball milling of CuO-Al and CuO-prealloyed Cu(Al) powder blends in dry and wet condition has been investigated by using X-ray diffraction (XRD), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM) techniques. Direct reduction of CuO by Al has resulted into Al₂O₃ dispersed Cu-matrix composite through a self-propagating reaction only during milling in dry condition. However, indirect reduction of CuO by prealloyed Cu(Al) resulted into formation of nano-Al₂O₃ dispersed Cu-matrix composite either by continued ball milling in dry condition or by subsequent thermal treatment of wet milled powder precursor. The influence of milling conditions, that is, milling speed, and milling media, on the occurrence of reduction of CuO by elemental Al or Al in prealloyed Cu(Al) during ball milling have been explained by considering their effects on the rise of powder temperature due to collisions between balls and powder particles, and the rate of reduction of ignition temperature of the reaction due to microstructural refinement. TEM investigation has revealed that the size of Al₂O₃ particles in the composite power blend formed by the indirect reaction route (CuO-prealloyed Cu(Al)) is much finer than the same in case of direct reaction route (CuO-Al). It is suggested that the kinetics of the reduction reaction in the indirect reaction route is relatively sluggish in nature and amenable to processing of large amount of nano-Al₂O₃ dispersed Cu-matrix composite powder for industrial purpose.     

基于碳纤维的新型自支撑电极制备方法

借鉴自支撑电极的制备原理,利用电化学沉积结合(NH₄)₂S₂O₈和NaOH沉积液进行表面处理等手段制备了基于碳纤维表面Cu(OH)₂纳米结构的自支撑电极,分析测试了碳纤维表面的微观形貌、表面元素组成及其分布和表面物质的晶型以及利用水热反应在其表面附着电化学物质MnO₂后的电化学性能。结果发现,当(NH₄)₂S₂O₈的浓度为0.43 g/L、NaOH浓度为30.48 g/L、处理时间为12 min时,由SEM观察发现碳纤维表面的Cu(OH)₂纳米纤维的直径、长度、数量都较适宜;XPS、XRD和EDS的测试结果,沉积液处理后碳纤维表面部分单质铜转化为Cu(OH)₂,此结构非常有利于电化学物质的负载而由此构成开放、具有核壳结构的高性能电极材料;恒电流充放电(GCD)测试结果表明此电极材料具有极快的充放电速度。因此本文首次成功地在碳纤维表面的铜层表面原位生长出Cu(OH)₂纳米纤维,为未来以超级电容器为代表的能源设备的性能提升和商业化应用开拓了一种新的电极制备方法。      

Zr含量对铸造AlSi7Mg0.4合金力学性能的影响

研究了添加Zr元素的重力铸造AlSi7Mg0.4合金的微观组织和力学性能.结果 表明,在含Zr的铸态合金中生成了(Al,Si)3(Zr,Ti)和π-Fe相,Zr的添加使合金的晶粒尺寸减小;经过T6热处理后富Fe相中的Mg和少量粗大的(Al,Si)3(Zr,Ti)相重溶到基体中,减小了金属间化合物的尺寸,生成了与基体有共...     

Effect of minor alloying with Al on oxidation behaviour of MoSi2 at 1200°C

Effect of Al alloying in small concentrations on oxidation behaviour of molybdenum di-silicide (MoSi₂) at 1200°C has been investigated. MoSi₂–2.8 and 5.5 at.% Al alloys possessed 0.5, and 2.5 at.% Al in solid solution, respectively, and dispersoids of -Al₂O₃. On the other hand, MoSi₂–9 at.% Al alloy possessed 3.1 at.% in solid solution in MoSi₂ and Mo(Si,Al)₂ phase, besides -Al₂O₃ dispersoids. The kinetics of oxidation of all the alloys followed a parabolic rate law. The oxidation rate was higher in the MoSi₂–Al alloys in comparison to MoSi₂, with weight gain values varying by an order of magnitude. The MoSi₂–5.5 and 9 at.% alloys demonstrated closely related oxidation characteristics and proved to be more resistant to oxidation than MoSi₂–2.8 at.% Al alloy. The oxide scale comprised of SiO₂ in MoSi₂, mixture of SiO₂ and -Al₂O₃ in MoSi₂–2.8 at.% Al alloy, and -Al₂O₃ in case of MoSi₂–5.5 and 9 at.% Al alloys. The mechanism of oxidation has been analysed using thermodynamic and kinetic considerations.     

Influence of Ultrasonic on the Dispersibility of ZrB2 Particles

To obtain the better ZrB₂/Al(OH)₃-Y(OH)₃ core-shell composite particles, ZrB₂ particles must be adequately dispersed during the coating process. In this article, the dispersibility of ZrB₂ particles in the ZrB₂ suspension is investigated via the sedimentation method. Through test and analysis, the dispersibility is rapidly increased with prolonging the ultrasonic dispersion time before 10 minutes. After 30 minutes, the sedimentation grads using ultrasonic dispersion basically reach the sedimentation balance, but the grads using mechanical agitating dispersion does not basically change after 5 minutes. The ultrasonic dispersion is one of more effective ways between ultrasonic and mechanical agitating dispersion, the dispersion time for 10 minutes is chosen in the dispersibility of ZrB₂ particles via ultrasonic dispersion.     

Reactions and Microstructure at Selected Ceramic/Metal Interfaces

The reactions of Ti and Zr with A1N, Al₂0₃and mullite were studied. The substrates were selected to represent a simple nitride (A1N), a simple oxide (Al₂O₃), and a complex oxide (mullite). The activities of the Ti and Zr were varied by dissolving them at 1 and 5 wt% in the 72Ag-28Cu eutectic composition, which is otherwise unreactive with the ceramics. Reactions were studied by measuring the variation of the alloy contact angle on the ceramic with time at temperature and by determining the compositions of interfacial reaction products. The reaction products were determined by SEM-liDS, EPMA and XRD analysis. Contact angles were lower for Ti alloys than for those containing Zr. Reaction products were primarily the nitrides of Zr and Ti for reaction with A1N and the respective oxides for reaction with A1₂0₃. Complex alloy phases were found in the metal away from the ceramic-metal reaction zone.