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1.
碳钢在微生物介质中的腐蚀电化学行为   总被引:4,自引:0,他引:4  
硫酸盐还原菌(SRB)生长代谢,溶液pH值从7.5下降到5.8,并在碳钢表面形成生物膜,改变了生物膜下碳钢表面的微环境,促进碳钢点蚀的形成,清除表面的腐蚀产物后,碳钢基体表面为分布不均匀的溃斑,发生严重的点蚀行为,而RB的活性和生物膜的结构诱发碳钢腐蚀的形成和生长,在微生物快速生长过程中出现明显的氢扩散电流峰,加剧碳钢的渗氢行为,采用电化学阻抗(EIS)研究了碳钢在微生物腐蚀过程中生物膜的结构与腐蚀相应的变化关系。  相似文献   

2.
杜艳芳 《大学化学》2019,34(6):33-37
采用线性扫描伏安法和交流阻抗法研究了碳钢在不同实验条件下的腐蚀规律,碳钢在碳酸铵溶液中的阳极过程为溶解、钝化、过钝化溶解,溶解初期在电极界面的传质为线性扩散控制;随着溶液温度的升高,阻抗谱表示为单一时间常数的容抗弧,容抗弧直径逐渐减小,电阻变小,碳钢的腐蚀速度增大;Cl~-浓度越大,钝化区域变小,碳钢更容易腐蚀;加入硫脲缓蚀剂,碳钢容抗弧直径增大,电阻变大,有利于保护碳钢。  相似文献   

3.
松香改性苯乙烯聚合物分子量及分子量分布的GPC测定   总被引:1,自引:0,他引:1  
本文利用凝胶渗透色谱测定新型高分子材料(苯乙烯-歧化松香树脂乙烯酯)的分子量及分子量分布,实验数据重视性较好。标准偏差为0.074,变异系数为3.360%。  相似文献   

4.
钢在中国大陆的大气腐蚀研究   总被引:12,自引:0,他引:12  
梁彩凤 《电化学》2001,7(2):215-219
本文分析了我国七个试验点十七种钢的八年大气腐蚀试验结果 .表明 ,对碳钢和低合金钢 ,危害最大的污染是二氧化硫及氯离子 ,与公认一致 .但是 ,二氧化硫仅在开始头 1- 2年内危害突出 ,其后作用明显下降 .对非耐候钢 ,湿热条件在短期里对腐蚀的影响并不大 ,但长期暴露危害作用非常大 ,如果同时存在污染 ,更会造成很严重的腐蚀 ,值得特别注意 .由于腐蚀情况与时间因素有关 ,碳钢、低合金钢在不同腐蚀环境中 ,暴露第一年所显示的大气腐蚀性规律与长期暴露所显示的不同 ,如果用短期暴露数据判断钢的耐蚀性或环境的腐蚀性 ,都会导致错误的结论  相似文献   

5.
松香改性特辛基酚醛树脂分子量GPC表征   总被引:1,自引:0,他引:1  
本文利用凝胶渗透色谱法(GPC),建立了最佳测试条件,测试了松香改性特辛基酚醛树脂的分子量(重均、数均、分布指数),相对误差为2.46%、标准偏差为1.49、变异系数为4.94%,数据重视性较好。本方法操作简单,准确度、精密度均达到罗高要求。为这一类型高聚物的分子量测定提供了科学依据.  相似文献   

6.
边丽  翁永基  许述剑 《化学通报》2006,69(3):207-210
腐蚀是一种复杂随机现象,可以用分形理论更好地描述。本文根据分形动力学过程,以一组基于不同表面条件下的腐蚀发生概率为参数,建立计算机模型来预测大气、土壤环境的金属腐蚀过程。计算结果和实际腐蚀特征吻合一致。此外,本文还讨论了幂函数腐蚀模型中指数n和各种腐蚀概率之间的定量关系,揭示了腐蚀发展规律。  相似文献   

7.
五氧化二钒中微量镁的测定   总被引:1,自引:0,他引:1  
本文采用共沉淀定量分离方法对五氧化二钒中所含微量镁进行极谱测定。检出限为1.5mg/L,线性范围为0~0.4mg/L。精确度为:标准偏差S=0.14,变异系数CV=1.92%;相对误差为2.3%.  相似文献   

8.
曲唑酮的两步法制备及对碳钢的缓蚀机理   总被引:4,自引:0,他引:4  
以3-氯苯胺、N-氯丙基二乙醇胺和吡啶三唑酮为原料,两步法制备出曲唑酮(TZD).通过动态失重、极化曲线与电化学阻抗谱研究了TZD在0.5 mol/L盐酸溶液中对20#钢的缓蚀性能;借助扫描电子显微镜、原子力显微镜、衰减全反射红外光谱与吸附活化参数分析研究了TZD在碳钢表面的作用机理.结果表明,TZD可显著降低碳钢在盐酸溶液中的腐蚀速率,缓蚀率随TZD添加浓度的增加而增大,随温度升高而降低;298 K下,添加6 mmol/L TZD时,缓蚀率达95.8%;TZD可自发吸附组装于碳钢表面,同时抑制腐蚀反应的阴、阳极过程,显著增加界面极化阻抗;吸附为放热过程,符合Langmuir等温式.理论计算结果显示,TZD倾向以平行取向组装于碳钢表面.  相似文献   

9.
咪唑啉酰胺在电偶电极表面的吸附行为   总被引:1,自引:0,他引:1  
采用原子力显微镜技术研究了有机阳离子缓蚀剂(咪唑啉酰胺)在电偶电极表面的吸附行为, 并探讨了其腐蚀抑制机理. 结果表明, 金属表面的过剩电荷较大地影响缓蚀剂分子的吸附行为. 在1%的NaCl溶液中, 碳钢电极表面带有过剩的负电荷;不锈钢电极表面带有过剩的正电荷;碳钢电极和不锈钢电极耦合后, 其表面分别带有过剩的正电荷和负电荷. 在耦合前阳离子缓蚀剂分子仅吸附在碳钢表面, 耦合后缓蚀剂分子在偶对的阴极(不锈钢)和阳极(碳钢)表面均有吸附, 但缓蚀剂分子在碳钢表面的吸附强度和覆盖度较之耦合前降低, 缓蚀剂的腐蚀抑制能力减弱.  相似文献   

10.
毛细管电泳用β-环糊精作改性剂分离血清中吗啡和可待因   总被引:3,自引:0,他引:3  
建立了血清中吗啡和可待因的毛细管电泳分离分析方法。讨论了电泳分离模式、缓冲液pH,β-环糊精(β-CD)浓度对分离的影响。吗啡和可待因检测限均为0.1μg/mL,不同浓度的萃取回收率分别大于92%和93%,迁移时间的相对标准偏差分别小于0.44%和0.39%,峰面积的相对标准偏差分别小于3.2%和4.1%。  相似文献   

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12.
A model to describe the settling behavior of fractal aggregates   总被引:16,自引:0,他引:16  
A model to predict fractal dimension from sedimentating fractal aggregates has been successfully developed. This model was developed using the settling rate and size data of fractal aggregates. In order to test the validity of the model, a purpose-built settling rig, equipped with lens with magnification of 1200x, which can capture images of particles/flocs down to 2 microm in diameter was used. The performance and technique of the settling rig were validated by comparing the measured settling rates of 30- and 50.7-microm standard particles with their theoretical settling rates calculated using Stokes' law. The measured settling rates were within 10% agreement with the calculated Stokes' velocities. The settling rates and sizes of the particles/flocs were analyzed using image analysis software called WiT 5.3. The maximum temperature gradient across the settling column was 0.1 degrees C, which effectively eliminated convective currents due to temperature differences in the settling column. A total of 1000 calcium phosphate flocs were analyzed. Calcium phosphate flocs with fractal dimensions varying from 2.3 to 2.8 were generated via orthokinetic aggregation. Measurements of fractal dimensions, using light scattering, were done simultaneously with the settling experiments and they were found to be constant. The fractal dimensions calculated using the model agreed with those obtained by light scattering to within 12%.  相似文献   

13.
The complex characteristics and mechanisms of aluminum pitting corrosion in a solar heating system were studied by the chemical immersion method and electrochemical techniques as well as fractal theory. The results showed that pitting corrosion of Al occurred in a tap water environment due to the local enrichment of Cl? ions. The higher the Cl? ions concentration, the more negative the critical pitting potential (Eb) of Al. A linear relationship between Eb and the logarithm of Cl? ions concentration was observed. The pitting corrosion mechanism of Al in neutral water was explained in terms of complexation corrosion theory. The corrosion surface images of aluminum immersed in tap water were captured and analyzed by image processing technique and box‐dimension method. The fractal characteristics of pit distribution, described by fractal dimension, have been identified. The fractal dimension of the pit distribution increased with the increase of immersion time and had the same trend as that of the weight loss. Fractal dimension can, thus, be used as an important parameter for quantitative evaluation of pitting corrosion of aluminum.  相似文献   

14.
The aim of this paper is to survey interlaboratory studies of performance data to produce highly permeable thin‐film composite (TFC) polyamide nanofiltration (NF) membrane in the form of flat sheet at bench scale. TFC polyamide NF membranes were fabricated via interfacial polymerization of 1,3‐phenylenediamine and trimesoyl chloride on porous polyethersulfone (PES) membrane. The NF membranes were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), and cross‐flow filtration. The AFM and SEM analyses indicated that a rough and dense film was formed on the PES support membrane. The permeability and NaCl rejection of the NF membrane prepared at the presence of camphor sulfonic acid as pH regulator and triethylamine as accelerator in the aqueous solution were 21 l m?2 h?1 and 70%, respectively. In order to estimate the repeatability and reproducibility standard deviations, the development of an interlaboratory study was conducted by measurements of permeation flux and salt rejection of the synthesized membranes. Repeatability standard deviation of the permeation flux data for the membrane based on optimum formulation was 1.99, and reproducibility standard deviation was 3.55. Also based on this trend, repeatability standard deviation of the salt rejection data was 1.57, and reproducibility standard deviation was 4.11. The American Society for Testing and Materials standard E691‐05 was used for data validation of the repeatability and reproducibility standard deviations and consistency statistics. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

15.
Electrochemical noise data in the presence of pitting corrosion were analyzed. A correlation between the intensity of the observed noise and mass loss of steel electrodes was recognized. The registered noise was decomposed into a set of band limited components using wavelet transform. It has been observed that the standard deviation of the chosen component was more strictly correlated with mass loss of electrodes than the standard deviation of the other components. The frequency band of the chosen component was adequate to the band where energy of transients, typical for pitting corrosion dominated. The measurement results were obtained only for the limited number of electrodes due to a very long time of noise observation.  相似文献   

16.
In this work, odd random phase multisine Electrochemical Impedance Spectroscopy (ORP-EIS) was used as a detection method for the onset of corrosion of coated steel. The possibility to use ORP-EIS as a rapid-screening test for corrosion was investigated. It is concluded that the detection of a non-linear behavior combined with a non-stationary behavior during the onset of corrosion can be used as a criterion in a rapid-screening test for corrosion of coated steel.  相似文献   

17.
静态失重法是一种测定酸化腐蚀速率的基本方法,但存在耗时长、操作繁琐等缺点。为了弥补静态失重法的不足,研究了容量法测定腐蚀速率的可行性,分析了两种方法所测结果存在差异的原因。结果表明,容量法与失重法测得的腐蚀速率有较高的一致性,其相对平均偏差未超过4%。最后根据接触角测试结果,分析了产生这种偏差的原因。  相似文献   

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