缓蚀型土壤降阻剂的制备及性能研究

发布时间：2018-03-15 06:06

  本文选题：土壤降阻剂　切入点：缓蚀　出处：《东北电力大学》2017年硕士论文　论文类型：学位论文

【摘要】：变、配电站接地系统常采用填充降阻剂的方法降低接地网接地电阻以达到接地设计要求,但研究发现降阻剂的使用会引起接地电极的腐蚀问题。本课题采用我国产量丰富的膨润土材料作为降阻剂基材,添加常用缓蚀剂钼酸钠与六偏磷酸钠,制备具有缓蚀作用的土壤降阻剂,以解决上述问题。同时,在该土壤降阻剂中添加优良的导电材料石墨,降低土壤降阻剂的电阻率,优化其降阻性能。主要研究内容如下:根据膨润土优良的吸附性能,通过溶液浸渍法,将钼酸钠及六偏磷酸钠与膨润土复合,制备缓蚀型土壤降阻剂。采用SEM分析方法对降阻剂进行形貌表征。以Q235A碳钢为工作电极,通过Tafel曲线及交流阻抗谱研究了反应时间、反应温度及缓蚀剂含量的变化对碳钢电极在该降阻剂中腐蚀情况的影响。结果表明:溶液浸渍法制备缓蚀型土壤降阻剂的最佳制备条件为水与膨润土的质量比为10:1、钼酸钠添加量为5.0 wt.%、六偏磷酸钠添加量为2.0 wt.%、水浴温度为25℃,反应时间为6.0 h。在该条件下制备所得降阻剂中,Q235A碳钢电极的腐蚀电位为-0.563 V,腐蚀电流为0.00647μA。为找出更简便的制备方法,通过物理球磨法将钼酸钠及六偏磷酸钠与膨润土复合,制备缓蚀型土壤降阻剂。以碳钢为工作电极,通过Tafel曲线及交流阻抗谱研究了球磨时间及缓蚀剂含量的变化对碳钢电极在该降阻剂中腐蚀情况的影响。结果表明:采用物理球磨法制备土壤降阻剂的最佳制备条件为球磨时间30 min,六偏磷酸钠添加量为1.6 wt.%,钼酸钠添加量为4.0 wt.%。该条件下制备所得土壤降阻剂中,Q235A碳钢工作电极的腐蚀电位为-0.599 V,腐蚀电流为0.0129μA。为优化降阻剂的导电性能,在降阻剂中添加石墨,考察不同石墨添加量对降阻剂性能的影响。结果表明:添加石墨会在一定程度上增大土壤降阻剂对Q235A碳钢的腐蚀性,加速碳钢电极表面的溶解速率,且当石墨添加量过大时会严重破坏降阻剂的吸水率。但添加石墨可以大大降低降阻剂的电阻率,当石墨添加量为15 wt.%时,土壤降阻剂的电阻率降低至5?·m以下,达到《接地降阻剂》中对接地土壤降阻剂电阻率的要求。最后,通过腐蚀失重实验、SEM表面形貌表征及电化学测试等方法探讨该缓蚀型土壤降阻剂的缓蚀机理。结果表明,碳钢试片在该缓蚀型土壤降阻剂中浸泡后,表面会附着一层均匀致密的保护层,从而减缓碳钢材料的腐蚀速率。
[Abstract]:In order to meet the requirements of grounding design, the grounding system of distribution station often uses the method of filling resistance reducing agent to reduce the grounding resistance of grounding grid. However, it was found that the use of resistance reducer would cause corrosion of grounding electrode. In this paper, the abundant bentonite material was used as the base material of resistance reducing agent, and the common corrosion inhibitors, sodium molybdate and sodium hexametaphosphate, were added. In order to solve the above problems, a soil resistance inhibitor with inhibition effect was prepared. At the same time, the resistivity of the soil resistance reducer was reduced by adding good conductive material graphite to the soil resistance reducer. The main contents are as follows: according to the excellent adsorption property of bentonite, sodium molybdate and sodium hexametaphosphate were combined with bentonite by solution impregnation. The corrosion inhibitor was prepared. The morphology of the inhibitor was characterized by SEM. The reaction time was studied by Tafel curve and AC impedance spectroscopy using Q235A carbon steel as working electrode. The effect of reaction temperature and corrosion inhibitor content on the corrosion of carbon steel electrode in the inhibitor was studied. The results showed that the optimum conditions for preparing corrosion inhibitor of soil by solution impregnation were as follows: mass ratio of water to bentonite was: 1. 10: 1, sodium molybdate 5.0 wt., sodium hexametaphosphate 2.0 wt., water bath temperature 25 鈩，

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