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TiO2 coating by gel oxidation

Abdullah, Hasan Zuhidi and Sorrell, C.C. (2013) TiO2 coating by gel oxidation. In: International Conference on Mechanical Engineering Research (ICMER2013), 1-3 July 2013, Kuantan, Pahang. (Unpublished)

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Abstract

This Gel oxidation is a thermochemical method for the production of an oxide film on a metallic substrate, where the metallic substrate is subjected to gelation by immersion in NaOH solution, followed by oxidation. These films are suitable for thicknesses of a few microns owing to the risk of cracking and discontinuity of the gel during drying and firing. However, the firing can have deleterious effects on the mechanical properties of the substrate. Continuous and discontinuous gelled and TiO2 films of submicron thickness were produced on high-purity Ti foil substrates (50 μm thickness) by soaking in NaOH solutions (0.5 M, 1.0 M, 5.0 M, and 10.0 M). Gelation involved soaking at 60°C for 24 hours. After drying in air for 24 hours, the samples were heated at 300ºC/hour and soaked for 1 hour in air at 400ºC, 600ºC, and 800°C. The compositions, microstructures, and thicknesses of the films were determined using: glancing-angle X-ray diffraction, Raman microspectroscopy, and field emission scanning electron microscopy (FESEM). Raman microspectroscopy revealed the formation of an amorphous sodium titanate gel layer following chemical treatment. As expected, the thickness of the gel layer increased with increasing NaOH concentration. However, the two highest concentrations (5.0 M and 10.0 M) resulted in cracking of the gel layer upon drying in air. TiO2 did not crystallise during heating at 400ºC but rutile formed directly upon heating at 600ºC and 800ºC.

Item Type: Conference or Workshop Item (Paper)
Uncontrolled Keywords: titania; thick films; gel oxidation; glancing-angle X-ray diffraction; raman microspectroscopy
Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK7800-8360 Electronics
Depositing User: Normajihan Abd. Rahman
Date Deposited: 13 Aug 2018 03:41
Last Modified: 13 Aug 2018 03:41
URI: http://eprints.uthm.edu.my/id/eprint/4076
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