| 低合金钢在海水中局部腐蚀的评价和机理研究 | |
| 甘阳 | |
| Subtype | 硕士 |
| Thesis Advisor | 林海潮 |
| 1998 | |
| Degree Grantor | 中国科学院金属腐蚀与防护研究所 |
| Place of Conferral | 中国科学院金属腐蚀与防护研究所 |
| Abstract | 论文针对低铪金钢在海水中局部腐蚀的自催化作用，研制了可变尺度的“闭塞”模拟电池，研究闭塞孔几何尺寸和面积比对低合金钢902，907，945，921和普通低碳钢A43自催化作用的影响，确定了闭塞模拟电池的适宜尺寸。通过测量自催化偶接电流密度随时间变化曲线和计算局部表面溶解电量，评价了902，907，921，945和A3钢的局部腐蚀速度，902＞A3＞945＞907＞921，结果和实海数据吻合，证明所研制的闭塞模拟电池能评价低合金钢的局部府蚀趋势。对进行自催化偶接实验的试样表面进行微观表面分析，发现不同多则种的局部溶解形貌有很大差异，闭塞孔表面腐蚀产物膜、表面具实溶解面积、残留碳化物的数量和分布都能影响自催化作用，提出“微观面积差异效应”和“碳化物弥散效应”分另来解答局部表面真实溶解面积、残留碳化物的分布和数量对自催化作用的影响。应用多重循环扫描恒电位极化方法，根据参数I_（max3）或S_3的大小可能快速、定量评价不同钢种自催化作用的强弱，所得结果与自催化偶接实验结果以及实海数据吻合。根据局部腐蚀过程中加速和阻滞因素的影响，并结合“徽观面积差异效应”和“碳化物弥散效应”的观点，可以解释902钢局部腐蚀速度异常大，921钢较好的耐局部腐蚀性能，几种钢的均匀腐蚀速度差别很小现象。基于自催化作用微观机理，提出了低合金钢在研制和作用方面注意的问题，作为提高低合金钢在海水中耐局部腐蚀性能的指导意见。 |
| Other Abstract | Although many factors such as the concentration difference of O_2 between the occluded area and bulk surface may initiate the localized corrosion of low alloy steels in sea water, the degree of the "self catalysis effect" is the direct and intrinsic factor which takes effects in the Occluded Corrosion Cavity (OCC) determines greatly the localized corrosion rate of low alloy steels in sea water. A new OCC simulated cell with varied dimensions of the occluded cavity was designed for appraising the degree of the "self catalysis effect" by measuring the short circuit current and calculating the relative quantity of coulomb, the results presented was in good accordance with that of low alloy steels immersed in sea water, 902>A3>945>907>921. A new multi-cycles scanning potentiostatic polarization (MCSPP) method was invented to appraise rapidly the relative degree of the "self catalysis effect". The microscopic studies of the sample after the occluded experiment presented that properties of films and the surface patterns of the low alloy steels and mild steel differ greatly from each other. The "microscopic area difference" (MAD) effect was initiated to explain the effect of the microscopic area difference on the degree of "self catalysis effect", and the "carbides dispersively strengthening" (CDS) effect to explain the effect of the distributions and quantities of carbide. According to the macroscopic and microscopic studies of the "self catalysis effect", we explained satisfactorily some complex phenomena. The general corrosion rate of different low alloy steels in sea water is approximately equal; the localized corrosion of steel 902 is much higher than other low alloy steels; the steel 921 presents a fairly good localized corrosion resistant property. Based on the microscopic analyses of the "self catalysis effect", some viewpoints on how to lower the localized corrosion rate of low alloy steels in sea water were presented. |
| Pages | 67 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.imr.ac.cn/handle/321006/17640 |
| Collection | 中国科学院金属研究所 |
| Recommended Citation GB/T 7714 | 甘阳. 低合金钢在海水中局部腐蚀的评价和机理研究[D]. 中国科学院金属腐蚀与防护研究所. 中国科学院金属腐蚀与防护研究所,1998. |
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