Investigation of the influence of Mg on the corrosion behavior of hard coated steel substrates

更新建议在中间结果和假设方面加强并集中了正在运行的项目的目标。这三个主要目标是实现的。首先用电化学方法验证预测的腐蚀防护模型，并将影响腐蚀行为的因素（面积比、涂层化学和结构性能）与涂层中镁的效率相关联。这些知识与腐蚀系统中镁的电化学行为相结合，可以开发具有增强腐蚀性能的硬涂层系统。其次，将通过电化学方法和结构分析研究与应用相关的混合靶沉积涂层腐蚀性能较差的原因。由此可以得到镁的结合状态和含氮量对腐蚀行为影响的信息。这是优化涂层工艺的先决条件，以在钢上生产与应用相关的耐腐蚀pvd硬涂层。第三个目标是开发一种基于电化学和光学检测技术相结合的短期测试方法来评估腐蚀防护效率。在调整测试参数后，该方法可以通过电化学参数和对指示缺陷的统计评估来定性和定量地表征涂层。此外，与涂层缺陷的直接关联成为可能，从而促进了更耐腐蚀涂层的开发。与传统的盐雾检测相比，具有更好的意义、灵敏度和效率。更新工程取得的成果应能加深对腐蚀防护机理、引发腐蚀和控制腐蚀动力学的影响因素的认识。这些新型硬质涂料的应用潜力可以预测，研究结果可以为今后耐腐蚀硬质涂料的发展提供参考。

The renewal proposal enhances and focuses the aims of the running project with regard to intermediate results and hypotheses. Out of this three major aims are conducted.At first the predicted corrosion protection model will be finally verified by electrochemical methods and the influencing factors on the corrosion behavior (area ratio, chemical and structural coating properties) will be correlated to the efficiency of magnesium in the coating. This knowledge in combination with electrochemical behavior of magnesium in the corrosion system enables a specific development of hard coating systems with enhanced corrosion performance.Secondly the reason for the worse corrosion behavior of coatings from application-relevant mixed-target deposition will be investigated by electrochemical methods and structure analysis. From this investigations information to the binding state of magnesium and the influence of nitrogen content on the corrosion behavior should be derived. This is a prerequisite for the optimization of the coating procedure to produce application-relevant and corrosion resistant PVD-hard-coatings on steel.The third aim is the development of a short-time testing method based on the combination of electrochemical and optical investigation techniques for the evaluation of the corrosion protection efficiency. After an adaption of testing parameters this methods enables the qualitatively and quantitatively characterization of the coatings by means of electrochemical parameters and statistical evaluation of indicated defects. Furthermore a direct correlation to the coating defects becomes possible which enhances the development of more corrosion resistant coatings. Compared to the conventional salt spray testing a better meaningfulness, sensitivity and efficiency can be expected.The achieved results in the renewal project should enhance the understanding of the corrosion protection mechanism as well as influencing factors initiating corrosion and controlling its kinetic. The application potential of these new hard coatings can be estimated and the findings can be used for the future development of corrosion resistant hard coatings.