This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Experimental Measurement of the Transportation Properties of Automotive Cataphoretic Paints
Annotation ability available
Sector:
Language:
English
Abstract
Total automotive paint systems generally include three different coating layers: a cataphoretic primer, a sealer, and a top coat. The top coat gives the final aesthetic to the system, and the cataphoretic primer is supposed to be the ultimate protective layer against corrosion as well as the adhesion promoter, being directly in contact with the metal (or with the surface-treated metal). For this reason, it is very important to control the diffusion rate, through the cataphoretic primer, of poisonous species such as chloride or cathodic delamination initiators; i. e. oxygen and water. Although numerous studies have been reported on the corrosion mechanisms affecting automotive body panels, (either primer coated or fully painted), little has been done with regard to the transportation properties of the different paint layers concerning species such as oxygen and water vapour that are usually considered to be rate determining in the degradation of those systems. We have attempted, in a first stage, to measure experimentally the transportation kinetics of such species in cataphoretic primers. To this aim, free films have been made with different compositions in terms of pigment/filler ratio. The influence of the curing temperature has also been investigated. The measurements of water vapour and oxygen permeabilities, together with Electrochemical Impedance Spectroscopy of the free films yields a very sensitive discrimination between the different systems and shows a good correlation with the results of other quality control testing carried out by the paint manufacturers.
Recommended Content
Authors
Topic
Citation
Barreau, C., Massinon, D., and Thierry, D., "Experimental Measurement of the Transportation Properties of Automotive Cataphoretic Paints," SAE Technical Paper 912296, 1991, https://doi.org/10.4271/912296.Also In
References
- Leidheiser, H. Jr. J. Adhesion Sci. Tech. 1 o 1 79 1987
- Massinon D. Dauchelle D. Proceedings of the 1rst Int. Conf. on Zinc and Zinc Alloy Coated Steel Sheet, GALVATECH'89 September 1989 Tokyo, Japan
- Massinon D. Thierry D. NACE 1991 Conference, Paper N o . 574 Cincinnati, OH, USA
- Kendig M. W. Meyer E. M. Lindberg G. Mansfeld F. Corrosion Science 23 o 9 1007 1983
- Thierry D. Barreau C. IRSID publication, RE 90/328 1990
- Jossic T. Charbonnier J. C. Dauchelle D. NACE 1988 meeting, Paper N o . 355 St Louis, MO, USA