电极材料对含S碱液电化学氧化脱硫的影响及应用

采用全玻璃电解池装置,辅助电极为Pt网,以含S碱液作为电解液.研究不同的电极材料对S化物电化学氧化脱S的影响.它们分别为Pt电极、石墨电极和Ru-Ti电极.结果表明,电极材料对S离子电化学氧化过程有显著影响.据此,选择了工业模拟实验的工作电极——Ru-Ti电极,研制了一套多级电化学脱除H2S工业模拟装置     

电极片接线方式对贮氢合金电化学性质的影响

本文报道了三种电极片接线方式对贮氢合金的电化学性能的影响。通过研究分析，认为带来影响的原因是电极片接线方式改变了电极片的表面状态，并且在充放电过程中影响了电极过程。     

离子液体对PbO_2电极电化学性能的影响

为了考察离子液体对钛基Pb O2电极电化学性能的影响,将离子液体1-乙基-3-甲基-咪唑四氟硼酸盐([Emim]BF4)添加到Pb(NO3)2混合电积溶液中,通过阳极电氧化沉积制备得到钛基β-Pb O2形稳阳极Ti/β-Pb O2,对其电催化氧化活性及稳定性进行了考察,并与采用F-和十二烷基磺酸钠(SDS)为电积溶液添加剂制备的带有中间层的电极Ti/Sn O2-Sb2O3/β-Pb O2进行了对比。结果表明,离子液体修饰电极材料的电催化活性和稳定性相比后者均有明显提高。对电极表面的SEM与XRD表征分析表明,添加离子液体制备得到的电极Ti/β-Pb O2活性层表面致密平整、结晶大小均匀、择优结晶取向发生明显变化。电化学循环伏安实验结果显示,电极Ti/β-Pb O2的析氧过电位(1.7 V)比Ti/Sn O2-Sb2O3/β-Pb O2(1.6 V)稍高。     

NiTi合金表面电化学氧化制备TiO2膜

采用恒电流阳极氧化法在NiTi形状记忆合金(SMA)表面制备完整致密且耐腐蚀的TiO2膜.通过对NiTi SMA和纯Ti在稀HCl中的动电位阳极极化曲线的分析,得到了选择性脱Ni阳极氧化电流密度工艺参数.试验采用稀HCl体系,以该工艺参数进行阳极氧化处理5min,在NiTi SMA表面制备出了完整致密的TiO2膜,并进行了其表面的SEM、XRD、XPS分析和NiTi SMA表面处理前后在模拟唾液fusayama中的对比腐蚀试验测试.结果表明:经阳极氧化处理的NiTi SMA表面形成了十几纳米厚的TiO2膜,且其耐蚀性有明显的提高.     

FeS阳极氧化电化学

以高温合成法制备了ＦｅＳ,用电位扫描、旋转电极、恒电位电解等技术研究了ＦｅＳ在电解液０．５ｍｏｌ／ＬＨ２ＳＯ４＋０．５ｍｏｌ／ＬＫ２ＳＯ４（２５℃,ＰＨ＝０．７０）中的阳极氧化过程。结果表明,ＦｅＳ阳极氧化过程遵循“活性氧化一钝化－－活性氧化”规律,在０．７￣１．４Ｖ之间出现钝化区。第一个活性经区的Ｔａｆｅｌ方程为η＝０．４６８＋０．０２８９ｌｎＪ,在高过电位区,ＦｅＳ阳极反应受固相扩散传质步骤控     

NiTi合金表面电化学氧化制备Ti02膜

采用恒电流阳极氧化法在NiTi形状记忆合金(SMA)表面制备完整致密且耐腐蚀的Ti02膜。通过对NiTi SMA和纯Ti在稀HC1中的动电位阳极极化曲线的分析,得到了选择性脱Ni阳极氧化电流密度工艺参数。试验采用稀HC1体系,以该工艺参数进行阳极氧化处理5 min,在NiTi SMA表面制备出了完整致密的Ti02膜,并进行了其表面的SEM、XRD、XPS分析和NiTi SMA表面处理前后在模拟唾液fusayama中的对比腐蚀试验测试。结果表明：经阳极氧化处理的NiTi SMA表面形成了十几纳米厚的Tio2膜,且其耐蚀性有明显的提高。     

用旋转圆柱电极研究铝表面氧化膜

采用恒电流极化、电化学阻抗测试等方法,通过旋转电极研究在不同转速下纯铝及铝合金在4 m mol/L的NaOH电解液中氧化膜的生成与脱落情况.结果表明:在未加极化时纯铝表面也会形成一层薄的氧化膜,基本认为这层膜为较为疏松的单层多孔层膜,膜的脱落随转速的增加而加快.极化后纯铝表面形成了有一定厚度的双层氧化膜,内层与铝基体结合紧密,在转动情况下也不易脱落,外层较为疏松,在转动时很容易脱落.铝合金由于合金化的影响很难形成稳定的氧化膜,且氧化膜在静态时就很容易脱落,转速对其影响不大.     

碳纤维对碳钢电化学腐蚀行为的影响

研究了碳钢和偶接碳纤维碳钢在模拟孔隙液中的腐蚀行为。结果表明,随着碳纤维偶接量的增加,碳钢的全面腐蚀速率有所增加。继续增加碳纤维含量对碳钢腐蚀性能的影响程度降低。     

表面改性对碳纤维及其复合材料性能影响的研究进展

综述了近几年国内外碳纤维表面处理的研究工作,重点报告了目前常用的液相氧化法、等离子聚合法、上浆法3种碳纤维表面处理技术的研究进展。通过总结和对比,分析了3种碳纤维表面处理的作用机理和工艺的优缺点,并综述了3种表面处理技术对碳纤维的表面形貌、强度、浸润性、界面性能以及复合材料的力学性能的影响。在此基础上,指出目前对碳纤维表面处理技术存在的问题,并给出相应的建议,为碳纤维表面处理技术的优化和研究应用提供参考和帮助。     

镍基合金表面电化学表面改性

分别在硼酸缓冲溶液(pH=8.4)和0.1mol/L H2SO4溶液中对镍基合金600和800进行电化学表面改性;对镍基合金表面氧化膜(改性前和改性后)进行动电位扫描、Mott-Schottky曲线测定以及利用光电流法绘制光电流谱。结果表明,镍基合金在酸性溶液中平带电位发生明显正移,载流子浓度升高,且在同样的电位范围呈现不同的半导体性质;电化学表面改性后,镍基合金生成的表面钝化膜平带电位没有发生明显变化,载流子浓度明显减小,表面钝化膜溶解的速度降低,耐蚀性能得到改善。     

SiC 涂层对不同碳基体氧化防护行为的研究

为了提高碳材料的抗氧化性能,采用料浆烧结法在石墨和C/C复合材料上制备了SiC 抗氧化涂层.测试了SiC涂层在1200℃的高温下对不同碳基体的氧化防护能力,利用扫描电子显微镜 (SEM)、X-射线衍射仪(XRD)对涂层结构进行分析.结果表明:SiC涂层对不同碳材料的抗氧化防护行为有很大差异,在1200℃的高温下SiC涂层对石墨具有较好的抗氧化性能,而对C/C复合材料的氧化防护性能较差.     

SiC涂层对泡沫炭高温抗氧化性能的影响

采用包埋法在中间相沥青基泡沫炭表面生成了一层致密的高温抗氧化碳化硅涂层,研究了SiC涂层对泡沫炭高温抗氧化性能的影响.通过热重分析仪(TG)对有、无SiC涂层的泡沫炭的抗氧化性能变化进行了分析,采用扫描电子显微镜(SEM)分析了SiC涂层的结构和形貌特征变化,同时在1 200℃空气气氛中对SiC涂层的抗氧化性能进行了测试.结果表明:SiC涂层使泡沫炭的抗氧化性能有了显著的提高,并且随着SiC涂层厚度的增加,泡沫炭的抗氧化性能也随之增强.     

炭化升温速率对中空多孔炭纤维孔结构的影响

以中空多孔聚丙烯腈(PAN)预氧化纤维为原料,固定炭化温度为800 ℃,时间为60 min时改变炭化升温速率制备了中空多孔炭纤维,借助于压汞法和SEM对其多孔结构进行表征,并对其影响规律进行了分析.结果表明,不同炭化升温速率下所得中空多孔炭纤维的孔径存在3个分布区域,分别为6～17 nm、90～430 nm和90 mm处附近,孔径分布的高峰在90～430 nm处.在此条件下,以5 ℃/min升温速率烧成纤维的孔隙率和比表面积分别为63.17%和88.672 m~2/g.SEM分析显示,随着炭化升温速率的升高,纤维的截面变形程度加剧,孔径增大.     

Oxidation Behavior of PAN-based Carbon Fibers and the Effect on Mechanical Properties

PAN-based carbon fibers were oxidized both in dry air and wet air in the temperature range of 400–600 °C. Kinetic laws are established that follow an Arrhenius-type temperature dependence. Oxidised fiber surfaces were investigated by SEM and AFM. Oxidation leads to the modification of surface morphology with the disappearance of the axial striations initially present. Then, residual properties were evaluated by failure tests in tension on single-filaments. Oxidation has a dramatic effect even for a low level of weight loss. The tensile failure stresses are reduced by 25–40 % for a mass loss of 2.5–5 %. This excessive embrittlement is more related to the creation of new defects by oxidation than a significant reduction in fiber cross-section area.     

Strength and Wear Behavior of Mg Alloy AE42 Reinforced with Carbon Short Fibers

In addition to the advantage of the lightweight of magnesium alloys, magnesium composites have moderate strength and elastic modulus. The proposed application of magnesium composites as diesel truck pistons makes it necessary to assess their wear performance. Little research data have been discussed on wear behavior of Mg alloy AE42 matrix and its composites. Thus, this paper reports wear behavior of magnesium alloy AE42(Mg–Al–Mn—RE; rare earth) and its composite AE42-C, which contains 23 vol% of randomly oriented carbon short fibers. Materials characterization, including density measurements, hardness testing, microstructures investigation, and compression testing at temperatures of 25, 150,and 300 °C, were conducted. Wear tests were performed under various loads and sliding distances. Wear mechanisms were also proposed based on the examination of worn surfaces using optical microscopy and scanning electron microscopy equipped with EDX(energy-dispersive X-ray spectrometry) analysis system. The hardness of AE42-23 vol% C composite is twice the hardness of the Mg matrix alloy AE42. Significant improvements to yield stress and compressive strength at temperatures of 25, 150, and 300 °C of the composite versus the AE42 alloy are achieved. Wear resistance of the composite is improved considerably versus that of the Mg alloy AE42 at the various sliding distances. Smearing of graphite on the worn surface produces a lubricating film that delays change from mild to severe wear of the composite, especially at high loads. EDX analysis of the worn surface shows oxidation of the matrix alloy at higher wear loads, and this mechanism decreases in the presence of carbon fibers under the same loads. Abrasive wear, oxidation, and plastic deformation are the dominant wear mechanisms for the alloy matrix AE42, whereas mainly abrasive wear is the wear mechanism of AE42-23 vol% C composite under the proposed testing conditions.     

In Situ Embedment of ZnS Nanocrystals in High Porosity Carbon Fibers as an Advanced Anode Material for Efficient Lithium Storage

ZnS is a promising material for lithium-ion battery anodes due to its abundant natural resources, simplicity of synthesis, and high theoretical lithium storage capacity. However, it needs to be optimized for its low conductivity and volume effect during the charge-discharge process. The traditional method of combining with carbonaceous materials is usually laborious, and the required sulfuration process may possibly result in the destruction of materials morphology. In this study, hybrid materials formed by the combination of ZnS nanocrystals and high porosity carbon fibers were synthesized by one-step electrospinning using zinc diethyldithiocarbamate and polyacrylonitrile as raw materials and poly (ethylene glycol)—block-poly (propylene glycol)—block-poly (ethylene glycol) as template. The method is simple and avoids the influence of sulfuration process on the morphology of materials. The composite presents a specific capacity of 592.2 mAh g⁻¹ under a current density of 1 A g⁻¹ after 1000 cycles. The porous structure significantly decreases the diffusion mean-free path of Li⁺ and inhibits the volume effect associated with the lithium storage process of ZnS. In addition, the 3D cross-linked carbon fibers improve the conductivity of materials. This study can serve as an inspiration for the development of other lithium storage composites.     

低碳钢箔片氧化原因探讨

介绍了用低钢箔片（挂片）在对Unicase密封箱式炉进行炉内碳势定碳分析时存在被氧化的情况。经过分析后认为低碳钢箔片的氧化（除操作失误外）是由于以下两种原因造成：（1）箔片在冷却腔冷却过程中其腔内的温度下降导致压力下降，从而空气进入冷却腔，而此时箔片的温度尚未冷却到200℃以下，箔片发生氧化。（2）由于冷却水的作用，使冷却腔的温度降至露点以下，冷却腔内气氛（与炉内气氛相同）中的水蒸气被凝结，液态的水对炽热的箔片造成了氧化，在此基础上，提出了改进措施。     

Characterization and Oxidation Behavior of Rayon-Derived Carbon Fibers

Rayon-derived fibers are the central constituent of reinforced carbon/carbon (RCC) composites. Optical, scanning electron, and transmission electron microscopy were used to characterize the as-fabricated fibers and the fibers after oxidation. Oxidation rates were measured with weight loss techniques in air and oxygen. The as-received fibers are ~10 μm in diameter and characterized by grooves or crenulations around the edges. Below 800 °C, in the reaction-controlled region, preferential attack began in the crenulations and appeared to occur down fissures in the fibers.     

碳钢高温氧化的实验研究

文章采用失重法对结构钢45#钢和工具钢T10钢的高温氧化进行了实验研究.实验表明,碳钢在加热温度为800～1 000 ℃加热时间为6 h范围内的氧化增重量最高可达到4.2 g,占总质量的14.0%;由计算得到的氧化回归方程与氧化曲线的相关系数可达到0.9以上,高温氧化烧损量与温度和时间均呈抛物线规律.     

Study of Oxidation of Carbon Fibers Using Resistance Measurement

Thermogravimetric analysis (TGA) is a useful and frequently used quantitative analysis technique to study the oxidation kinetics and mechanism of carbon fibers (CFs). An alternative method involving the resistance measurement of CFs during oxidation is proposed to study the oxidation behavior of CFs in this study, which might be also applied to other carbon materials. Experimental results from resistance measurements at different oxidation temperatures show qualitative consistency with those obtained using the TGA technique for the same type of fiber. A comparison between these two techniques is discussed.