Magnesium powderMagnesium powder, for pyrotechnic and chemical uses, is made by reducing metallic magnesium into particles in the shape of curly shavings to give maximum surface per unit of weight. It is produced in four grades: cutting powder, standard powder, special specification, and fireworks powder. Cutting powder is finely cut shavings in a matted condition, made from magnesium of 99.8% purity. Standard powder is loose powder in fineness from 10 to 200 mesh. Fireworks powder is 100 mesh. The speed of ignition increases rapidly with decreasing particle size. A 200-mesh powder is used for flashlight powder, and a 30- to 80-mesh for more slowly burning flares. For flares, magnesium gives a brilliant light of high actinic value. Incendiary powder, for small-arms incendiary ammunition, is magnesium powder mixed with barium peroxide. Ophorite is an English name for magnesium powder and potassium perchlorate used as an igniter for incendiaries. The material known as goop, used in fire bombs, is a rubbery mixture containing magnesium powder coated with asphalt, gasoline, and chemicals.
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