ABSTRACT
Experimental Details . . . . . . . . . . . . . . . . . . . . . . . . 702
Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 702
Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 703
Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 703
Characterization Techniques . . . . . . . . . . . . . . . . 703
Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 704
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 708
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . 710
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 710
The upper limit to the thickness of dense silica coatings on hydroxylated surfaces that can be obtained with
conventional coating techniques was found to be extended significantly by coating with monosilicic acid. An
example with submicrometer a-alumina particles as a substrate showed dense, uniform coatings up to at least 800 A˚ thick. The silica coatings and coating mechanism were characterized by chemical analysis,
electrokinetic potential, nitrogen surface area (Brunauer-Emmett-Teller), particle size, x-ray photo-
electron spectroscopy, diffuse reflectance Fourier transform infrared spectroscopy, secondary ion mass
spectroscopy, and transmission electron microscopy.
