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Iowa State University and Ames Laboratory researchers have developed a process to passivate magnesium powders through the creation of a protective film

Passivation of magnesium using fluorine-containing gases is well known and extensively used in the die casting industry, and a single-step process to create a thin shell containing fluorine is the subject of previous Ames Laboratory patent.  This newest invention describes a process in which fluorine-containing gases are introduced into the atomizer spray chamber following a first reactive species, resulting in a oxy-fluorine rich scale on the surface of the magnesium powder during free-fall of the powders.  Powders produced in this way show reduced flammability versus commercial compositions (ignition temperature of 635°C versus 525°C).

• Increased ductility of film yields better protection than native oxide film.

• Significantly increased onset temperature for ignition reduces flammability hazard during production, handling, transport and storage.

Passivated magnesium powders for improved safety

“Investigation of a novel passivation technique for gas atomized magnesium powders”, A. Steinmetz, MS Thesis, Iowa State University, 2011.