Print ISSN : 0021-9592
Materials Engineering and Interfacial Phenomena
Effects of Annealing on the Morphology and Porosity of Porous TiO2 Films Fabricated by Deposition of Aerosol Nanoparticles
Masaru KuboYuki MantaniManabu Shimada
Author information

Volume 48 (2015) Issue 4 Pages 292-299

Download PDF (2080K) Contact us

The present study investigates the impact of post annealing of TiO2 nanoparticulate films on their crystallinity, mechanical strength, and morphology. Non-agglomerated and amorphous TiO2 nanoparticles of 46 nm diameter were synthesized in a plasma field, and were subsequently deposited on substrates to form nanoparticulate films. The films were annealed at various temperatures in the range of 100–1,200°C. Phase transformations from amorphous-to-anatase and from anatase-to-rutile were observed at 400°C and at 1,000°C, respectively. The high rutile transformation temperature was considered to be due to a tensile field induced by shrinkage of the film. The as-deposited film and the films annealed at below 400°C had poor mechanical strength. Conversely, the films annealed at over 500°C were strengthened by necking of the nanoparticles. The size of nanoparticles changed with increasing temperature. Annealing at 100–300°C caused the nanoparticles to shrink to approximately 30 nm. The nanoparticle diameters changed only slightly when annealed at 400–600°C because the annealing time was insufficient for changes to manifest. Annealing at 700–900°C caused the nanoparticle diameter to increase to approximately 50 nm because of sintering and coalescence of the nanoparticles. The diameter of the nanoparticles annealed at over 1,000°C became approximately 200 nm because of densification during the anatase-to-rutile transformation. The porosities of the films annealed at below 900°C were over 80%. However, the porosities of the films annealed at over 1,000°C decreased significantly due to densification.

Information related to the author
© 2015 The Society of Chemical Engineers, Japan
Previous article Next article

Recently visited articles