Prediction of Blistering in Coating Systems.
Prediction of Blistering in Coating Systems.
(1030 K)
Pommersheim, J. M.; Nguyen, T.
Organic Coatings for Corrosion Control. ACS Symposium
Series No. 689. Proceedings. American Chemical
Society. Chapter 11. April 1998, Washington, DC,
Bierwagen, G. P., Editor(s), 137-150 pp, 1998.
Keywords:
coatings; blistering
Abstract:
Models based on diffusion and osmotic theory were
developed for the growth of water-filled blisters at the
substrate beneath organic coatings. Blister growth was
considered to occur either over concentrated spots of
impurity located at the point of blister initiation, or
over a surface containing a uniform distribution of
impurity. The solutions to both models had similar
mathematical forms: the blister radius, surface area,
volume, osmotic pressure, all vary directly as
fractional powers of time. Exeprimental data for KHSO4
as impurity was used to test the models. Blister volume
was found to vary as t0.5 (vs. t0.75 for the theory) and
as Ms (vs. Ms0.75), where Ms is the mass of KHSO4.
Deviations between data and theory were discussed in
terms of the contact angle, blister initiation, ion
concentrations within the blister, saturation,
disbondment, and possible mechanical shifts.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899