Corrosive delamination and ion transport along stretch-formed thin conversion films on galvanized steel
By Posner, R.; Fink, N.; Giza, G. & Grundmeier, G.
Published in Surface and Coatings Technology
NULL
2014
Abstract
Microdefects on thin conversion film coated Zn hot-dip galvanized steel (HDG) sheets were generated by stretch-forming and verified by cyclic voltammetry, which revealed higher anodic and cathodic current density levels on the pre-damaged samples. The data were compared to the kinetics of electrochemically determined ion transport processes along strained conversion film covered substrate surfaces in humid air and along uniaxially stretched epoxy/conversion layer/zinc interfaces exposed to the same corrosive environment. Analysis with a Scanning Kelvin Probe indicated increased driving forces for ion transport, but verified accelerated kinetics of cathodic delamination only in some areas of the stretch-formed epoxy coated substrates. This finding reflected a rather insignificant macroscopic acceleration of corrosion processes for samples that were strained by up to 15%. Similarly, accelerated oxygen reduction driven electrolyte spreading on bare conversion film covered HDG surfaces was verifiable only on a μm scale during initial process stages. This confirmed that stretching-induced defect formation increased the electrochemical activity of the substrates, but neither effectively nor significantly promoted the kinetics of ion transport along the sample surfaces in the present case. As a result, stable epoxy/conversion layer/zinc interfaces were maintained.
Microsoft is Ending Support for Windows 7
Microsoft will discontinue support for Windows 7 on January 14, 2020 which means Gamry will also be discontinuing support for Windows 7. If you are upgrading to Windows 10, like many companies and institutions, you need to be running Version 7 of our s oftware . Please note that only USB and Ethernet-based instruments can run in Version 7. Eligible users can download the latest version of our software through our online Client Portal .
If you haven't already registered your instrument, you can do so through the Client Portal .
Please email Technical Support if you have any questions regarding this transition. Please be sure to include your instrument model and serial number when contacting us.