Tungsten Blue Oxide Physical properties

Physical properties. The physical properties of the TBO, such as particle size, size distribution, and internal porosity, are of importance for the subsequent hydrogen reduction process. Size, size distribution, and shape of the particles are related to the starting APT as a consequence of the crystallization process and do not alter significantly during the decomposition process, while the internal porosity is a result of the blueing process. The degree of porosity is influenced by the calcinations parameters (time, temperature). The specific surface area in commercial TBOs can vary between 1 and 15m²/g.

Both macromorphology and microporosity of the TBO particles determine the permeability and thus the diffusion resistance of a TBO powder layer, which is a determining factor for the material exchange (H₂→H₂O) during reduction.