Measurement of porosity in ceramic coatings by thermogravimetric volatilization of liquids

Bradley D. Craig, Lorraine F Francis, Lloyd Abrams

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

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 μm. The standard deviation of the TVL measurement was smaller for thicker coatings (e.g., ≥20 μm). 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.

Original languageEnglish (US)
Pages (from-to)3317-3320
Number of pages4
JournalJournal of the American Ceramic Society
Volume79
Issue number12
DOIs
StatePublished - Dec 1996

Fingerprint Dive into the research topics of 'Measurement of porosity in ceramic coatings by thermogravimetric volatilization of liquids'. Together they form a unique fingerprint.

Cite this