Differences between films and monoliths of sol–gel derived aluminas

• Published in: Thin solid films 2010-10, Vol.519 (1), p.42-51
• Main Authors: Dressler, M., Nofz, M., Klobes, P., Dörfel, I., Reinsch, S.
• Format: Article
• Language: English
• Subjects: Alumina; Aluminum oxide; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Microstructure; Phase transitions; Physics; Porosity; Sol gel process; Sols; Sol–gel processing; Specific surface; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thermal evolution; Thin film structure and morphology; Thin films
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2010.07.057

This work compares thin layers (films) and monoliths prepared from alumina sols with respect to their microstructure, thermal evolution, porosity and specific surface area. After heat treatment at similar temperatures, films and monoliths showed the same qualitative changes in porosity and specific surface area. However, some marked quantitative differences were detected. Film fragments had a lower open porosity, a lower specific surface area and a narrower pore size distribution. Furthermore, the thermal evolution showed a markedly different burnout of organic components between films and monoliths. The observed differences between films and monolith can be explained by the ageing history of the sols during sample preparation.