【作者】 陶蕾；

【导师】 宋诗哲；

【作者基本信息】 天津大学 ， 应用化学， 2009， 博士

【摘要】 本文工作结合国家自然科学基金重大项目“材料在自然环境腐蚀过程中原位实时检测新技术的基础与应用研究”(No.50499335)和国家科技支撑计划项目“海洋工程结构腐蚀与防护检/监测技术及工程应用”(No.2007BAB27B04),将数字图像处理技术以及电化学测试技术引入到自然环境材料腐蚀监检测研究中,主要研究成果如下:建立了适用于实验室和大气暴露现场的腐蚀形貌图像采集系统,确立合适的腐蚀形貌图像采集参数和图像预处理方法。对大气暴露现场铝合金试样的腐蚀形貌图像进行跟踪采集,建立基于小波图像分析判别金属材料大气腐蚀程度的方法。根据图像能量值的变化,实现对试样腐蚀程度定性和定量判断,实验结果与腐蚀失重数据分析所得结果基本一致。采用图像识别技术对LC4CS、LY12CZ铝合金周期降雨模式加速腐蚀试样的腐蚀形貌进行了研究:运用小波图像分析技术对滤波处理后的图像进行分解并提取子图像的能量值。利用典型相关技术分析图像能量值与试样腐蚀失重之间的典型相关性,提出图像特征值δ的概念。以特征值δ作为考察周期降雨试验加速性的指标,分析各试验因子对试验加速性的影响,得到加速腐蚀试验的最佳水平组合,其结论与腐蚀失重数据分析结论一致。结合数字图像技术和色度学相关原理,针对老化过程涂层表面出现的色彩变化,建立基于颜色特征的涂层材料老化失效性能检测方法。采用HSV颜色空间对腐蚀试样表面的变色程度进行描述,提出表征涂层材料表面色彩变化的腐蚀性能参数CP,实现对涂层试样相对老化失效程度的判别。构建并完善以电化学噪声(EN)技术为基础的铝合金大气腐蚀现场检测系统,考察不同电化学噪声监测系统对测试环境的敏感性,获得自然大气环境中铝合金大气腐蚀的电位电流噪声和噪声电阻变化,结果表明所构建的现场检测系统能够实现铝合金大气腐蚀的检测,实验数据也充分反映了表面薄液膜变化对铝合金腐蚀的影响。运用EIS和EN技术研究青岛海洋环境中暴露不同周期的环氧铁红、醇酸铁红以及环氧富锌底涂层体系在3.5%NaCl溶液中的腐蚀行为结合数字图像技术,对涂层材料表面锈蚀状况的定量评价,建立环氧富锌底涂层图像灰度值分布和电化学特征参数之间的关系模型,并具有较高的拟合精度。更多还原

【Abstract】 Corrosion rates of metals exposed in environmental tests are often determined from the weight changes of specimens after corrosion product stripping. However, visual inspection or weight change measurements are not appropriate techniques to evaluate non-uniform corrosion and the early stage corrosion. In this paper, the digital image processing and electrochemical testing methods were used in aluminium alloy atmospheric corrosion and coating materials’corrosion detection research. The main conclusions are as follow:The corrosion morphology image acquisition systems were established which can be used both in the laboratory and filed. The suitable parameter to capture images and corresponding pre-processing methods were discussed and determined. In Beijing atmospheric corrosion exposure station, the image acquisition system was used to capture the early stage corrosion morphology of aluminium alloy specimens. After the denoise treatment, wavelet transformation was applied to decompose the improved images and energies of sub-images were extracted as character information. Based on the variation of image energy values, the corrosion degree of aluminium alloy specimens was qualitatively and quantitatively analyzed. The conclusion was basically identical with the result based on the corrosion weight loss.Periodic rain tests have been carried out for simulating atmospheric corrosion of aeronautical LC4CS and LY12CZ aluminium alloys. The digital image preprocessing and analysis method based on wavelet transformation was used to study the corrosion morphology of aluminium alloys samples. The canonical correlation analysis was used to gain the correlative coefficient between the energy values and the corrosion loss, through which an image feature parameterδwas extracted and discussed. The influences of orthogonal experiment parameters on acceleration were analyzed according to image feature parameterδwith analysis of variance (ANOVA) method, and the optimal parameters for accelerated corrosion test were also obtained. The result was shown to be consistent with that from weight loss method.An inspective method of corrosion surface damage of coating materials by using the digital image processing technology and correlative theories of colorimetry was discussed. The corrosion morphology image acquisition system was established, and it was used to capture the corrosion morphology of coating specimens, which were exposed in the field exposure station. To describe the discoloration of corrosion surface damages, we use the HSV color model. The Euclidean Distance between uncorroded image and corrode image was extracted as color characteristics parameter CP. This analysis develops a method for automated identification system of discoloration of corrosion damages, and is supposed to be an important step in the promising direction in corrosion inspection.The atmospheric corrosion field detective system of aluminium alloy based on electrochemical noise (EN) technology was presented. The environment sensitivity of different EN data acquisition systems was discussed. The electrochemical potential and current noise were acquired by aluminum alloy atmospheric corrosion sensor in natural atmosphere as well as the noise resistance. The result of simulation experiments showed that the filed detective system established was suited for detection of aluminium alloy atmospheric corrosion; the data collected were able to reflect the influence that transformation of surface thin liquid film on aluminium alloy corrosion.The electrochemical impedance spectroscopy (EIS) technology, electrochemical noise (EN) technology and digital image processing method were used to evaluate the degradation of the Q235 steel samples with different prime coating which have been exposed to the splash zone of Qingdao sea area with different times. The specimens’suface corrosion was quantitatively analyzed by image analysis. And with a high correlative coeddicent, 0.93, the linear relational model between the gray distribution of epoxy rich zinc primer coating specimens and electrochemical parameter-low frequency domain |Z0.01Hz| has been studied.更多还原