问题引导式推进金属腐蚀与防护的实验教学

Question Facilitated Experimental Teaching in Metal Corrosion and Protection

电极极化是大学化学实验"金属的腐蚀与防护"中的核心知识点,是一个部分超出大学化学大纲要求但又是电化学应用非常普遍的一个概念。在实验讲解过程中,根据电压测量的问题,借助"化工原理"的多相反应过程剖析了极化的本质;通过浏阳河大桥的实例,分析了金属腐蚀的危害及其电化学驱动力,提出了腐蚀防护的一般思路;在上述讨论基础之上,通过"逆向思维"引出了极化在金属腐蚀防护中具体的体现形式——钝化。最后结合具体实验过程,使学生深入理解了电极电势这样一个化学因素导致的、又受多相反应过程控制的重要物理量。

Electrode polarization is the core knowledge of the university chemistry experiment ＂ metal corrosion and protection＂. It is partly beyond the University Chemistry Syllabus but is a concept widely used. During the experiment explanation stage, the essence of the polarization was analyzed using multiphase reaction process of ＂chemical engineering principles＂, initiated from the voltage measurement problem; the harm and driving force of the electrochemical corrosion was discussed based on the example of the Liuyang River Bridge, which leads to the general routes of corrosion protection; then the ＂reverse thinking＂ was proposed based on the above discussion, which leads to the application of polarization in corrosion protection - - passivation. After the specific experimental process, students could finally understand the electrode potential which is an important physical concept not only initiated by chemical factors but also controlled by multiphase reaction process.