高强度海洋工程钢中夹杂物诱发腐蚀的微纳米电化学机理与钙调控

针对海洋强国战略工程对高强低合金钢日益增加的需求，和海洋环境下夹杂物诱发低合金钢局部腐蚀机理的认知瓶颈，本项目将以Ca处理调控780MPa级高强海工钢为研究对象，采用微区电化学试验方法分析钢中(Ca, Al, Mg)OxSy -TiN复合夹杂化学结构、尺寸、夹杂/钢基体界面和基体晶格畸变等结构特征对局部腐蚀的微观交互作用机制，揭示Ca含量对夹杂物诱发局部腐蚀过程的影响规律，探明夹杂物诱发局部腐蚀的临界尺寸效应，研究局部腐蚀的热力学和动力学过程，在微纳米尺度分析腐蚀过程中表面电势、电流敏感性、局部腐蚀电流和局部电化学阻抗等微区电化学信息的演变规律，建立夹杂诱发局部腐蚀萌生的微纳米电化学机理模型。本项目的研究成果不仅能为夹杂物诱发局部腐蚀机理的研究提供新思路，还能促进微区腐蚀电化学理论和腐蚀学科的发展与完善。同时可为我国新一代780MPa级耐蚀高强海工钢的研发提供理论依据，具有重要的科学意义。

In view of the increasing demand for high-strength low-alloy steels for the strategic project of Marine power and the cognitive bottleneck of the micro-electrochemistry mechanism of localized corrosion induced by inclusions in Marine environment, this project will take Ca treated control 780MPa high strength mrine steel as the research object, and use micro-electrochemical test method to analyze the micro-interaction mechanism of localized corrosion of the (Ca, Al, Mg) Oxsy-TiN inclusion chemical structure, size, the inclusion-adjecent matrix interface characteristic, and the lattice distortion of the inclusion adjecent matrix. Reveal the influence of Ca content on the process of localized corrosion induced by inclusion. Identify the critical dimension inclusion induce local corrosion effect. Thermodynamic and kinetic processes of localized corrosion induced by inclusions will be investigated, and the Volta potential, current sensitivity, local corrosion current and electrochemical impedance evolution mechanism in the localized corrosion initiation process will be analyzed at micro and nano scale. The micro-electrochemical mechanism model of localized corrosion induced by inclusion will be established.This research can not only provide new ideas for the research on the mechanism of localized corrosion induced by inclusions, but also promote the development and improvement of micro electrochemical corrosion theory and corrosion discipline.At the same time, it can provide theoretical basis for the research and development of new generation 780MPa corrosion resistance high strength marine steel in China, which has important scientific significance and practical application value.