ISSN:
0142-2421
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Physics
Notes:
Silica, derived from Si(OC2H5)4, was studied on high surface area titania and zirconia powders using ion scattering spectroscopy (ISS) and Auger electron spectroscopy (AES) with depth profiling. After a large exposure and thermal processing of Si(OC2H5)4, more silicon was detected by AES on TiO2 (Si/(Si + Ti) = 50%) than on ZrO2 (Si/(Si + Zr) = 40%). With ISS, however, the reverse was found; the Si signal was 92% of the total metal on ZrO2 but only 70% on TiO2. Moreover, when the silica-covered oxide surfaces were depth-profiled with Ar+ (2 kV, 4 μA), the fraction of silica, based on ISS, decreased rapidly from 92% to 55% during the initial 100 s for ZrO2 but remained about 70% over the first 150 s for TiO2. The results strongly support a model in which Si(OC2H5)4 decomposes to form a thin film of SiOx which completely covers ZrO2, while on TiO2, particles of SiOx and/or mixed oxide layers form which leave titania exposed. On ZrO2, the estimated thickness of the SiOx film is 0.24 nm.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/sia.740111005
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