Dependence of oxidation rate of WC powder on particle size
Isothermal oxidation experiments on WC powders revealed a systematic dependence of oxidation rate on powder particle size. Oxidation was followed by measuring the change in mass of the WC powder as WC is converted to WO3. Fine powders oxidized more quickly than coarse powders because for the same initial mass the fine powder had a larger surface area. Measurement of the change in mass with time were shown to resolve differences in mean size of 0.1 μm, and possibly less, between separate batches of powder. A theoretical expression for the change in mass with time of spherical particles has been derived which compares well with experimental measurements and which can also be used with appropriate assumptions to calculate the initial powder-size distribution.
KeywordsOxidation Polymer Particle Size Experimental Measurement Spherical Particle
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