Silicon dioxide , corrosion product

The aluminum flakes can be coated with aluminum oxide and/or silicon dioxide in the liquid phase before the CVD process to reduce the reactivity of the metal and to create multilayer color effects. These pigments show strong angle-dependent coloristic effects (color travel) [5.158]. Metal halogenides are difficult to use as gas-phase precursors for metal oxide coating because of the reactivity of the metal flakes and the corrosion of steel in chloride atmospheres. The use of TiCU and water vapor was described about ten years ago. However, no commercial products have, as yet, been introduced. 

Moundless Containing high sulphate ion and silicon dioxide Not reported Not reported Open-mouth pit morphology, no mounds of corrosion products present on such pits... 

The MFEs are coated particles similar to TRISO fuel with the outer diameters of about 2 mm. They consist of 1.5-1.64 mm diameter uranium dioxide spherical kernels coated with 3 ceramic layers. The inner layer, called a buffer layer, is made of 0.09 mm thick porous pyrolythic graphite (PyC) with the density of 1 g/cm, providing space for gaseous fission products. The second layer is made of 0.02 mm thick dense (1.8 g/cm ) PyC, and the outer layer is 0.07-0.1 mm thick corrosion resistant silicon carbide (SiC). The fourth, outer PyC layer is assumed to be absent. SiC protection layers, manufactured by chemical vapour deposition (CVD) method, create resistance of graphite components against water and steam at high temperatures. Small fuel elements are able to confine fission products indefinitely at temperatures below 1600°C. 

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