【作者】 袁博宇；

【导师】 李威；

【作者基本信息】 中国矿业大学 ， 机械电子工程， 2014， 博士

【摘要】 金属材料的腐蚀问题遍及国民经济和国防建设的各个部门。据统计，金属腐蚀每年给一个工业国家造成的损失约占其国民生产总值(GNP)的3%-3.5％。金属的电化学腐蚀是金属腐蚀的主要形式，研究金属的电化学腐蚀行为和机理、阐明影响金属电化学腐蚀的因素是金属防腐的关键。尽管国内外已有大量的研究试图解释金属的腐蚀机理，但迄今为止对金属的腐蚀过程还有许多基础的科学问题尚未解决，造成这种情况的主要原因是缺乏有效的在线检测方法。因此，发展现场、实时的观测手段是研究金属电化学腐蚀过程的重要途径，不仅具有重大的科学意义，而且还具有重要的实际应用价值。本文以建立一种适合研究金属电化学腐蚀过程的全息在线检测方法为目标，首先设计适合观测金属电化学腐蚀过程的全息测试实验系统，根据腐蚀过程的特点设计全息图像处理算法，重建全息图的相位分布以实现电极/溶液界面动态变化的实时定量测量，再根据电极过程中电极/溶液界面的扩散传质模型，以经典电化学体系为测试对象验证全息测试系统和相位重建算法的准确性和可靠性，最后在验证系统测试结果合理的基础上利用该系统研究典型的电化学腐蚀体系，探索这些体系的腐蚀机理。主要开展了以下四个方面的工作：1.设计并实现了观测金属电化学腐蚀过程的全息测试系统。以马赫-曾德尔干涉仪为基础设计全息干涉光路系统，现场、实时检测电极/溶液界面的动态变化，利用CCD图像采集系统记录全息干涉图像，并利用计算机和DSP视频信号处理器分析全息视频图像。搭建了全息测试实验系统的硬软件平台，将全息测试与电化学测试结合同步观测金属的电化学腐蚀过程。2.对干涉条纹图像处理算法进行了研究。根据金属电化学腐蚀过程的特点，以相移技术为基础设计了一种适合本实验系统的全息图像处理算法，结合空间相移和空间频域滤波方法求解金属电化学腐蚀过程电极/溶液界面浓度变化引起的物光波前相位变化，开发了相应的全息图像处理程序，实现了对电化学腐蚀过程的定量分析。3.定量研究了电极/溶液界面的扩散传质过程。以典型电极反应过程为研究对象，测量了电化学过程中电极/溶液界面的浓度分布变化、扩散层厚度、反应离子扩散系数等重要参数，并将测试结果同经典模型和文献数据做比较，从不同的角度验证了全息测试系统的有效性、测量数据和结果的准确性和可靠性。4.利用全息测试方法研究了典型电化学腐蚀体系的腐蚀行为和机理。分别以铜在含氯离子环境和铁在酸性腐蚀介质的阳极过程为研究对象，配合常规电化学方法，通过改变Cl－浓度、外加磁场等因素，研究了上述体系阳极溶解过程中界面离子种类和表面膜组成的动态变化，为深入探讨相关腐蚀体系的电化学腐蚀机理、完善相应的理论模型提供了可靠的实验依据。结果表明，全息测试系统实现了金属电化学腐蚀过程中电极/溶液界面浓度变化、扩散层厚度的动态、定量测量，并根据界面扩散层厚度随时间的变化关系拟合了反应离子的扩散系数，测量结果精度较高，并且与理论模型和文献数据较为吻合；通过对电化学腐蚀体系的实例研究表明，全息测试方法获得了其他测试手段难以得到的新信息，为阐明Cu/NaCl、Fe/H2SO4等电化学腐蚀体系的腐蚀行为和机理提供了实验依据，并完善了相应的理论模型。本文的研究不仅为检测金属的电化学腐蚀过程提供了新的实验方法，为开发新的金属腐蚀监/检测仪器打下实验和理论基础；同时也为揭示金属的电化学腐蚀机理提供新的实验数据，为开发和研究新型高效的缓蚀剂和新型耐蚀合金提供实验与理论依据。更多还原

【Abstract】 The problem of metallic corrosion influences various fields of the domesticeconomy and national defense. The total annual costs due to corrosion inindustrialized countries are estimated to be about3%-3.5%of the gross nationalproduct. The electrochemical corrosion of metals is the main form of corrosion. Thestudy on behaviors and mechanisms of the electrochemical corrosion is veryimportant since the understanding of its factors plays a significant role in corrosionprevention. The metallic corrosion mechanisms have been extensively studied as oneof the typical nonlinear phenomena in electrochemistry. However, the basic problemsremains exist everywhere in corrosion science. The proposed reasons are shortage ofeffective on-line measurement methods. Therefore, the development of newobservation techniques in real time is an important way for the understanding ofelectrochemical corrosion processes and mechanisms, which is not only significantfrom the scientific aspect, but also important in practice.The main objective of this dissertation is to build a digital holographic methodsuitable for on-line observation of electrochemical corrosion processes. Firstly, theholographic testing system and the algorithm are designed. Secondly, the classicelectrochemical system is tested by the holographic system to verify the reliability ofthe system and the validity of algorithm. Thirdly, the holographic system will beemployed to study the mechanisms of typical electrochemical corrosion processes.The main content is concluded as follows.1. A field-based holographic testing system has been built up to measure thedynamic changes at the electrode/electrode interface during electrochemical corrosionin real time. The hardware and software of the holographic testing system have beendeveloped. The digital holographic method and traditional electrochemical techniqueswill be combined to study the electrochemical corrosion from different perspectives.The holograms can be recorded by CCD image acquisition system and then processedby PC or DSP.2. The algorithm of holograms has been studied. A phase unwrapping suitable forthe holographic system is developed based on phase-shifting technique. The spatialphase-shifting method and the space frequency domain filtering method are combinedto realize the phase changes of the object wave-frong at the electrode/electrolyte interface caused by the concentration changes during electrochemical corrosionprocesses. The softwave for holograms processing has been developed to analyze thedynamic processes quantitatively.3. The mass tansfer processes at the electrode/electrolyte interface have beenmeasured quantitatively. The concentration changes, diffusion layer thickness and thediffusion coefficient of reaction ions in several typical electrode reaction processeshave been measured and then compared to the classic model and reference data. Theaccuracy of the measured data has been confirmed and the effectiveness of theholographic system has been validated.4. Several typical electrochemcial corrosion systems have been studied by theholographic method. The digital holographic method has been combined with thetraditional electrochemical techniques to study the copper corrosion in chloridesolution and the iron corrosion in the sulfuric acid solution from different perspectives.The experimental research will focus on the effects of chloride, pH and externalmagnetic field on the electrochemical corrosion processes. The results have given newinsight into the corrosion models and mechanisms.The research results indicate that the holographic system can be employed tomeasure the dynamic changes of concentration changes, the thickness of diffusionlayers and the diffusion coefficient of reaction ions. The holographic measurementresults match well with the theoretical model and the data in the reference, indicatingthat the system has high accuracy and good reliability. The holographic method canobtain new information, which provides a reliable experiment basis for the study ofthe Cu/NaCl and Fe/H2SO4systems. The corresponding theoretical models of thesystems have been improved. It is concluded that the dissertation not only providesmethods and data for the study of the electrochemical corrosion processes but alsolays a new potential foundation for corrosion inhibitors, anti-corrosion alloys andcorrosion-monitoring instruments.更多还原