Pore evolution and solvent transport during drying of gelled sol-gel coatings: Predicting `springback`
- Univ. of Delaware, Newark, DE (United States). Dept. of Mechanical Engineering
- Sandia National Labs., Albuquerque, NM (United States)
- Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemical Engineering
The sol-gel method is a convenient method for producing ceramic coatings with a wide range of properties and for a wide range of applications. Brinker and Scherer (1990) have shown that the properties of the ceramic coatings are sensitive to the processing conditions used to coat the film onto a substrate and drying conditions used to remove solvents from the gelled coating. This paper reports predictions of drying phenomena in deformable porous gel coatings (i.e. a porous solid elastic network filled with air or solvent). Initially, a gelled coating is saturated with solvent, but as it dries, liquid-vapor menisci begin to recede into larger pores and the gel becomes a partially-saturated porous medium. The tensile capillary pressure in the liquid causes a compressive deformation on the solid skeleton and a consequent reduction in thickness and pore-size of the coating. A theory coupling the large deformation of the solid skeleton to capillary pressure in the interstitial liquid is used to predict the course of drying of dip-coated porous gel coatings. The theory predicts a springback effect in late stages of drying as the effects of capillary pressure diminish, which matches with experimental observations.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- OSTI ID:
- 533027
- Report Number(s):
- CONF-9607189--
- Journal Information:
- Drying Technology, Journal Name: Drying Technology Journal Issue: 6-8 Vol. 15; ISSN DRTEDQ; ISSN 0737-3937
- Country of Publication:
- United States
- Language:
- English
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