Morphology. As noted earlier, low temperature and dry conditions largely suppress any CVT of tungsten and lead to the formation of metal sponges, which are pseudomorphous to the oxide precursor (APT, H2WO4). They consist of very fine, polygonal and polycrystalline metal particles. With increasing temperature and humidity, individual tungsten grains form by CVT over comparably large distances. The particles are faceted and commonly exhibit the characteristic shape of the cubic metal. Well-faceted crystals, showing growth steps and being partly intergrown, are characteristic for very humid conditions (high temperature, large powder layer height).
Please visit our website: www.tungsten-powder.com to find more information.
没有评论:
发表评论