氢对X80钢在土壤模拟溶液中电化学行为的影响

在不同的充氢电流密度和充氢时间下对X80钢进行电化学充氢。测量了不同充氢条件下X80钢在鹰潭土壤模拟溶液中的极化电阻和腐蚀速率。结果表明,随着充氢电流密度由1 mA/cm2增加至20 mA/cm2,X80钢的自腐蚀电位负移,电荷转移电阻Rt由1 176 Ω·cm2降至909 Ω·cm2,双电层电容由0.000 16 μF/cm2增加至0.001 7 μF/cm2,腐蚀电流密度从3.322 mA/cm2 增加至 6.880 mA/cm2。当充氢时间由1 h增加至5 h,电荷转移电阻Rt由1 522 Ω·cm2降至749 Ω·cm2,双电层电容由0.000 14 μF/cm2增加至0.00 75 μF/cm2,腐蚀电流密度从2.91 mA/cm2 增加至5.01 mA/cm2。以上表明,电化学充氢使X80钢表面的薄弱点的阳极溶解率和金属离子的浓度高增加。氢加速阳极溶解,最终的结果是发生较高的腐蚀敏感性。     

Hydrogen induced cracking of X80 pipeline steel

The hydrogen-induced cracking (HIC) behavior of X80 pipeline steel was studied by means of electrochemical charging, hydrogen permeation tests, tension test, and scanning electron microscopy (SEM). The experimental results indicate that the increase of charging time and charging current density or the decrease of the solution pH value leads to an increase of the hydrogen content in X80 steel, which plays a key role in the initiation and propagation of HIC. It is found that the majority of macro-inclusions w...     

X65管线钢电化学充氢后在土壤中腐蚀行为

针对油气管道长距离输送所产生土壤质地差异大的工况条件,因氢引起的管道腐蚀问题越来越被人们所关注.基于极化曲线法和电化学阻抗谱法研究了充氢的X65管线钢在格尔木、大港站、大庆站、拉萨站4种模拟土壤溶液中的电化学腐蚀行为.试验结果表明:在同一种土壤溶液中,X65管线钢的开路电位随着充氢时间的增加逐渐降低.不同充氢条件下的X65管线钢在格尔木、大港站、大庆站、拉萨站4种模拟土壤溶液中的极化曲线都只表现出活化溶解状态,而未出现活化-钝化转变区,腐蚀电流密度越来越小,腐蚀速率越来越慢.对EIS进行拟合得出电荷转移电阻R_ct随充氢时间t变化规律,R_ct在4种土壤溶液中大小依次为格尔木<大港站<大庆站<拉萨站,与极化曲线的分析结果一致.     

Hydrogen-enhanced dislocation emission, motion and nucleation of hydrogen-induced cracking for steel

The change in dislocation configuration ahead of a loaded crack tip before and after charging with hydrogen was in situ investigated in TEM using a special constant deflection loading device The results showed that hydrogen could facilitate dislocation emission, multiplication and motion The change in displacement field ahead of a loaded notch tip for a bulk specimen before and after charging with hydrogen was in situ measured by the laser moire interferometer technique. The results showed that hydrogen could enlarge the plastic zone and increase the plastic strain The in situ observation in TEM showed that when hydrogen-enhanced dislocation emission and motion reached a critical condition, a nanocrack of hydrogen-induced cracking ( HIC) would nucleate in the dislocation-free zone (DFZ) or at the main crack tip. The reasons for hydrogen-enhanced dislocation emission, multiplication and motion, and the mechanisms of nucleation of HIC have been discussed     

Corrosion rate of hydrogenation to C110 casing in high H2S environment

The corrosion behavior of C110 bushing at high temperature and high pressure with a high H₂S/CO₂ was studied, and a basis for the materials selection of sour gas well bushing was provided in H₂S, CO₂ and saline coexisting environment. Under acidic condiction, hydrogen atoms greatly entered into the material and caused the material properties changed. Weight loss method was used to study the corrosion rate of hydrogen charging samples and original untreated samples in simulated oil field environment. PAR2273 electrochemical workstation was used to examine the electrochemical performance of samples untreated, hydrogen charging after reacting in autoclave. The corrosion product film was observed through SEM. The experimental results show that sample with hydrogen charging has a much more obvious partial corrosion and pitting corrosion than the untreated blank sample even the downhole corrosion speed of bushing is increased after being used for a period of time. Polarization curve shows the corrosion tendency is the same between sample with or without hydrogen charging and corrosion tendency is reduced by corrosion product film. A layer of dense product film formed on the surface of samples provides a certain protective effect to the matrix, but cracked holes which will accelerate partial corrosion of the sample were also observed.     

多孔碳包覆硅微球于锂离子电池负极中的应用

为了缓解纯硅负极材料在充放电过程中带来的巨大体积效应并降低电解质与电极之间的副反应程度,提出了一种简单高效的硅碳复合材料合成方法.以P123为分散剂、葡萄糖为碳源,利用水热法制备P-Si/C复合材料.结果表明,制备得到的复合材料可以极大地缓解充放电过程中产生的体积效应.当复合材料作为锂电池负极时,其首次放电比容量为1 800 mA·h/g,在500 mA/g电流密度下经100次循环后,其放电比容量能够稳定维持为521 mA·h/g,呈现出良好的循环性能.     

固定型VRLA电池并联充电研究

对不同荷电态的固定型VRLA电池进行了并联充电过程的观察研究。结果表明,流经各个电池的电流是按照电池荷电态的不同自动调节的。在充电过程中,原来荷电态较高的电池充电电流由小逐步增大;原来荷电态较低的电池充电电流由大逐步减小,最终各个电池的充电电流趋于一致。试验同时还证实了恒电压并联充电可以改善蓄电池的均匀性,有利于延长蓄电池组的使用寿命。     

环境介质和应变速率对 ABS 拉伸行为的影响

本文研究了ＡＢＳ树脂在环境介质中的慢应变率拉伸行为。结果表明：慢应变率拉伸试验可用于快速评价ＡＢＳ的耐环境应力开裂。     

Fracture mechanism of TiAl intermetallics caused by hydride and atomic hydrogen

Hydrogen embrittlement (HE) of TiAl intermetallics was studied at room temperature. The results showed that there were two forms of HE in TiAl intermetallics, i.e. hydride HE and atomic HE. Most of hydrogen in TiAl intermetallics was transformed into hydrides at room temperature. The hydride exists as (TiAl)H_x for a low hydrogen concentration while it exists in several forms for a higher hydrogen concentration. Stress intensity factor K_(IC) decreased with increase in hydride concentration. K_(IC) decreased further when TiAl intermetallics were charged cathodically with hydrogen in 1 mol/L H_2SO_4 solution. Stress intensity factor during hydrogen charging K_(IH) was about 50％ K_(IC). 20％ of the decrease was caused by hydrides while 30％ was caused by atomic hydrogen. Mechanism of HE caused hydrides was the same as any other second phase in nature. Delayed fracture caused by atomic hydrogen resulted from hydrogen induced local plastic deformation.     

Effect of deteriorated microstructures on stress corrosion cracking of X70 pipeline steel in acidic soil environment

In order to investigate stress corrosion cracking (SCC) of X70 pipeline steel and its weld joint area in acidic soil environ-ment in China, two simulating methods were used: one was to obtain bad microstructures in heat affected zone by annealing at 1300°C for 10 min and then, quenching in water; the other was to get different simulating solutions of acidic soil in Yingtan in south-east China. The SCC susceptibilities of X70 pipeline steel before and after quenching in the simulating solutions were analyzed...     

磁脉冲焊接的数学模型

从飞板冲击的动力学方程出发,建立了磁脉冲焊接过程的动力学模型,推导了接触点产生射流的临界速度与被焊工件的密度、屈服强度、几何形状与装配间隙的关系,其中充电电压作为可调工艺参数.采用所建立的模型计算出焊接铝合金1050与镁合金AZ31、铝合金5A03和铝合金5A06所需的充电电压,成功实现了上述2种异种材料的磁脉冲焊接,验证了所建立模型的正确性.     

电解充氢及退火热处理与ZL114合金的力学性能

充氢后的铝合金试样在空气中放置一段时间后，其力学性能与充氢前比不降反升.由此想到，若将充氢试样进行退火热处理，可望获得更佳的效果.以ZL114为试验合金，对比测定了在空气中放置和退火后的试样与原来的充氢试样的力学性能，观察了它们的断口形貌.为缩短试验周期、突出试验结果，便于对比，采用了浓度为1?mol/L的HCl溶液.结果表明，退火热处理明显改善了充氢试样的延伸率和缩面率，断口中出现韧窝状凹坑.因此，可用此法快速析出试样中的氢，减轻及消除氢对其力学性能的影响.     

Behavior of stress corrosion cracking in a magnesium alloy

Slow strain rate testing (SSRT) was employed to study the stress corrosion cracking (SCC) behavior of ZE41 magnesium alloy in 0.01 M NaCl solution. Smooth tensile specimens with different thicknesses were strained dynamically in both longitudinal and transverse direction under permanent immersions at a strain rate of 10⁻⁶ s⁻¹. It is found that ZE41 magnesium alloy is susceptible to SCC in 0.01 M NaCl solution. The SCC susceptibility of the thinner specimen is lower than that of the thicker specimen. Also, the longitudinal specimens are slightly more susceptible to SCC than the transverse specimens. The SCC mechanism of magnesium alloy is attributed to the combination of anodic dissolution with hydrogen embrittlement. Funded by the National Natural Science Foundation of China (No. 50771093)     

Anode oxidation of HCHO in THPED-containing electroless copper plating solution

The electrochemical mechanism of anode oxidation of HCHO in electroless copper plating solution with N, N, N', N'-tetrakis(2-hydroxypropyl)ethylenediamine (THPED) was investigated by measuring cyclic voltammetry curves and anodic polarization curves. Three different oxidation peaks occur at the potentials of-0.62V (Peak 1), -0.40V (Peak 2) and -0.17V (Peak 3) in the anode oxidation process of THPED-containing solution. The reaction at Peak 1, a main oxidation reaction, is the irreversible reaction of adsorbed HCHO with hydrogen evolution. The reaction at Peak 2, a secondary oxidation reaction, is the quasi-reversible reaction of adsorbed HCHO without hydrogen evolution. The reaction at Peak 3 is the irreversible oxidation of anode copper. The current density of Peak 1 increases gradually, that of Peak 2 remains constant and that of Peak 3 decreases with the increase of HCHO concentration. The current density of Peak 3 increases with the increase of THPED concentration and the complexation of THPED promotes the dissolution of anode copper.     

偶氮染料在活性炭纤维电极上的伏安特性

为了进一步明确偶氮染料在活性炭纤维电极上的电化学行为,在一个以活性炭纤维为工作电极、铂为辅助电极的三电极体系中,考察了苋菜红在活性炭纤维电极上的伏安特性。实验结果表明：（1）ACF电极与Pt电极析氢与析氧电位相近,Pt电极作为供电电极的存在对苋菜红在ACF电极上的伏安特性无影响;（2）负极化时,ACF具有较大的充电电流;（3）苋菜红在-0．1～-08V点位区间内存在电还原与电吸附的可能性,在0．6-1．4V存在电氧化可能性。     

废液对电解煤浆制氢的影响

为了探究工业废液对电解煤浆制氢的影响,在电解煤浆制氢体系阳极电解质中添加3种工业废液：洗气水、硫磺水、碳化水,分析废液添加前、后的电流密度-电压曲线,研究废液加入对氢气电流效率和产氢速率的影响以及废液体积分数和搅拌速率对电解电流密度的影响. 结果表明,3种废液不改变煤浆初始电解电位,但影响煤浆电解速率,其中洗气水、硫磺水废液可以有效地增大电流密度,提高电解速率;洗气水废液的加入不改变电解煤浆的氢气电流效率,但随着洗气水体积分数的增大,电流密度呈现先急剧增大再略微降低的趋势;电解废液煤浆速率受搅拌速率的影响,提高搅拌速率使传质增强,电流密度增大.     

智能锂电池充电器设计

为解决锂电池的快速充电问题,设计一种具有电压和电流检测功能的智能锂电池充电器系统,并给出了相关单元模块电路及其驱动程序的流程图。该设计以MSP430单片机为控制核心,对电池进行电压电流采集,通过判断电池所处的充电状态,调整PWM（Pulse Width Modulation）波的占空比,以实现高精度控制充电。实验结果表明,该智能充电器可安全地进行锂电池的快速充电,耗时约1h,比一般充电器（2～3h）的充电速度有显著提高,从而有效缩短了锂电池的充电时间。     

电动汽车用电池智能化快速充电研究

基于电池快速充电基本原理,制定了电动汽车用电池的分段恒流充电方案。根据对分段恒流充电试验结果的分析,对其控制策略进行了调整：按容量梯度法确定分段恒流充电终止控制参数,适当减小各段恒流值下降梯度,并将电池温度设为充电安全保障控制参数。调整方案后的充电试验结果表明,这种分段恒流充电控制方法可实现动力电池的智能化快速充电,有效缩短充电时间、提高充电效率。     

独立光伏发电系统高效充电控制器设计

针对小功率独立光伏发电系统中铅酸蓄电池使用寿命短、充电效率低的问题,提出基于放电脉冲的3阶段充电方法.该方法通过放电脉冲控制铅酸蓄电池的自放电,以增大铅酸蓄电池的可接受充电电流,使铅酸蓄电池能够完全吸收光伏电池组件输出的电能,提高独立光伏发电系统的充电效率.该方法结合最大功率跟踪算法协调铅酸蓄电池与光伏电池组件之间的工作关系,提高独立光伏发电系统的工作效率.根据这一思路设计具有高充电效率的独立光伏发电系统控制器.与传统控制器相比,它不仅提高了光伏电池组件的利用率,加快了对蓄电池的充电,而且可以保护蓄电池并延长使用寿命.     

电动汽车充电机充电策略设计

为了实现通用型电动汽车充电机对电动汽车的快速充电,研究了电动汽车各种充电方法以及蓄电池SOC检测方法,给出了充电拓扑图.通过采样电动汽车蓄电池端电压、电流以及温度等判断充电模式,结合采用恒流、带放电脉冲和低恒压充电3种方式对蓄电池进行充电.仿真结果验证了快速充电的合理性.