Fürbeth W, Stratmann M
Lehrstuhl für Korrosion und Oberflächentechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91058, Erlangen, Germany.
Anal Bioanal Chem. 1995 Oct;353(3-4):337-41. doi: 10.1007/s0021653530337.
The applicability of a new experimental technique - the Scanning Kelvinprobe - for the analysis of the delamination of polymer films from galvanized steel is discussed. Defect ions having direct access to the zinc/ polymer interface will diffuse along this interface, a process, which can be monitored by the Kelvinprobe in a very early state with a high local resolution. After incorporation of ions a galvanic element is formed, the local cathode being at the delamination front, where oxygen is reduced, and the local anode at the zinc coated defect. For the model polymer under investigation the interaction between the film and the substrate is weak and the rate determining step for the delamination is the diffusion of cations from the local anode to the local cathode. An exposure to a highly CO(2)-containing atmosphere before the delamination prolongs the incubation time of delamination. If there is no zinc layer at the defect, an anodic delamination mechanism occurs. Zinc is dissolved under the polymer film, while the steel surface is cathodically protected.
讨论了一种新的实验技术——扫描开尔文探针——在分析聚合物薄膜与镀锌钢脱层方面的适用性。能够直接接触锌/聚合物界面的缺陷离子会沿该界面扩散，这一过程可通过开尔文探针在非常早期的状态下以高局部分辨率进行监测。离子掺入后会形成一个电化电池，局部阴极位于脱层前沿，在此处氧气被还原，而局部阳极位于镀锌缺陷处。对于所研究的模型聚合物，薄膜与基材之间的相互作用较弱，脱层的速率决定步骤是阳离子从局部阳极向局部阴极的扩散。在脱层之前暴露于高含CO₂气氛中会延长脱层的孕育时间。如果缺陷处没有锌层，则会发生阳极脱层机制。锌在聚合物薄膜下溶解，而钢表面受到阴极保护。
