Synthesis and electrophoretic deposition of tin oxide (Sn02)

Taib, Hariati (2009) Synthesis and electrophoretic deposition of tin oxide (Sn02). PhD thesis, University of New South Wales.

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Abstract

Submicron tin oxide (SnCh) was obtained from thermal decomposition of tin oxalate (SnC2C>4) precipitated at room temperature from a mixture of solutions of tin (II) chloride (SnC^) and oxalic acid (H2C2O4).Aqueous precipitation of SnC204 was firstly investigated. Variation of synthesis parameters included starting material concentrations, addition methods and mixing times. This resulted in the formation of SnC204 particles with different morphologies, namely subangular equiaxed and elongated prisms. Occasional intergrowths and secondary nuclei were also seen. Upon calcination, SnC>2 powder was observed to be tacky and subsequent grinding was found to cause nanosized SnC>2 particles to agglomerate into variable sized plates. However, the particle size and morphology of the SnC>2 powders were found to have no obvious correlation with the SnC2C>4 precipitation conditions. Aqueous-alcohol precipitation was developed, based on the previously conducted aqueous precipitation. SnC2C>4 of elongated prismatic morphology was precipitated, but, the SnC>2 obtained was different from that obtained from aqueous precipitation in that it consisted of smaller nanosized Sn02 particles (upon calcination of larger SnC2C>4) and platy agglomerate formation was avoided (avoidance of grinding procedure). From both of the precipitation methods, it was inferred that the prismatic morphology was the preferred form of SnC204. SnC204 formation was also found to be influenced by overall concentrations in the precipitating system, which affected the ionic collision frequency and diffusion distance, resulting in variable SnC204 particle sizes and morphologies. The tackiness of the SnC>2 powder led to further investigation of Sn02 powder constituents, which then revealed that they were contaminated with alkali impurities, which initially were present in the distilled water. Although an extended leaching procedure was not found to be successful, a processing window of 1 hour for SnC>2 was observed.

Item Type:Thesis (PhD)
Subjects:T Technology > TA Engineering (General). Civil engineering (General) > TA401-492 Materials of engineering and construction. Mechanics of materials
ID Code:1696
Deposited By:Normajihan Abd. Rahman
Deposited On:28 Sep 2011 12:17
Last Modified:28 Sep 2011 12:17

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