Ceramics surface structures

Microfabrication techniques Optical and compact discs Ceramic surface structures Catalyses... 

Kokubo, T., Kushitani, H., Sakka, S., Kitsugi, T. and Yamamuro, T. (1990) Solution able to reproduce in vivo surface-structure changes in bioactive glass-ceramic A-W. Journal of Biomedical Materials Research, 24, 721-734. 

As described earlier, many EM techniques including in situ ETEM, STEM, HRTEM, image analysis and EEELS are being pushed to their limits by researchers to study surfaces and ultrafine particles (or clusters) which are thought to be active species. Eor catalysis, metal particles are, in general, supported on ceramic substrates. Detection of supported particles less than 10 A (1 nm) in size is possible by HRTEM however, caution must be exercised in interpreting the size and surface structure of the metal particles since the surface structure is obscured by the support contrast, as demonstrated by calculations. 

Since catalytic oxidation is a surface reaction, an inexpensive support material is normally coated with the noble metal. The support material can be made of ceramic, such as alumina, silica-alumina, or of a metal, such as nickel-chromium. The support material is arranged in a matrix shape to provide high surface area, low pressure drop, uniform flow of the waste gas through the catalyst bed, and a structurally stable surface. Structures that provide these characteristics are pellets, honeycomb matrices, or mesh matrices. 

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