Flake particle Aluminium Powder 99.7% pure, with a maximum particle size selectable by the buyer. maximum particle size options: 149 micron (100 mesh), 74 micron (200 mesh), or 49 micron (300 mesh). we also manufacture and supply 74 micron (200 mesh) crucible powder alloyed â??magnalium powderâ??. 56:44 ratio of magnesium : aluminum. alloyed into a block, and then crushed and ball milled to a powder with a maximum particle size of 74 micron (200 mesh)..