ALUMINUM POWDER

New Zealand Herald, Volume LXXI, Issue 21924, 6 October 1934, Page 7 (Supplement)

ALUMINUM POWDER

SIZE OF THE FLAKES How thin is a flake of aluminum bronze powder? "This question, an important one in the paint industry, 1 ' says a writer, "has been answered through research laboratories. In average size such a flake of powder is not much thicker than the wall of a soap bubble. It would take more than 100 flakes, laid one on top of another, to make a pile as thick as newspaper. When aluminum became commercially available its powder was known as " aluminum bronze powder," which is a misnomer because it is not a lironze. It has an aluminum purity content of more than 99 per cent., and is used as the pigment portion of aluminum paint. It is different from other pigments, in, that the individual particles are flaky instead of granular. "The effectiveness of aluminum paint as a protective covering for surfaces, outdoors and in, conies from the minute metal flakes, impervious to light and moisture. The microscope reveals the fact that the flakes overlap in layers in the dried paint film, actually forming, in effect, a very thin layer of metal over the painted article. The measurement of flak, thickness is peculiarly difficult because the aluminum flakes are too small to handle, even under the microscope. An ingenious method has been devised, however, which requires as measuring instruments only a balance and a common ruler."