Measurement of porosity in ceramic coatings by thermogravimetric volatilization of liquids

Journal Article · Sun Dec 01 04:00:00 EST 1996 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1996.tb08112.x· OSTI ID:422742

Craig, B D; Francis, L F ^[1]; Abrams, L ^[2]

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1. Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemical Engineering and Materials Science
2. DuPont Chemical Co., Wilmington, DE (United States). Central Research and Development

A simple gravimetric method was developed to determine the open porosity in ceramic coatings. The coating`s pore space was filled with a liquid and the weight loss on volatilization of the liquid was measured in a thermogravimetric analyzer. This thermogravimetric volatilization of liquids (TVL) method was used to characterize the porosity in titania coatings, alumina/aluminum phosphate coatings, and free-standing films of alumina. Several liquids were used; ethylene glycol and 1,3-propanediol gave the best results due to their low volatilities at room temperature. The measured porosities of the ceramic coatings ranged from 30% to 80% and the pore sizes (as determined by SEM and mercury porosimetry) ranged from 0.1 to 15 {micro}m. The standard deviation of the TVL measurement was smaller for thicker coatings (e.g., {ge}20{micro}m). Porosities determined by TVL were within typically 5--10% of those determined by mercury intrusion porosimetry on identical samples. Characterization of a series of alumina/aluminum phosphate coatings showed a decrease in porosity consistent with expectations based on density and SEM observations. TVL is nondestructive, can be used for small volumes of sample, and when combined with SEM, provides a good means to characterize coating porosity and pore structure.

• Sponsoring Organization: USDOE
• OSTI ID: 422742
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 12 Vol. 79; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
ALUMINIUM PHOSPHATES
EVAPORATION
EXPERIMENTAL DATA
GLASS
IMPREGNATION
LIQUIDS
PORE STRUCTURE
POROSIMETERS
POROSITY
SAMPLE PREPARATION
SCANNING ELECTRON MICROSCOPY
SUBSTRATES
THERMAL GRAVIMETRIC ANALYSIS
TITANIUM OXIDES