Improved Stability of Gas Atomized Reactive Powders Through Multiple Step In-Situ Passivation

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

Description:
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).

Advantage:
• 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.

Application:
Passivated magnesium powders for improved safety

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

Development Stage:
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Patent Information:
Title App Type Country Serial No. Patent No. File Date Issued Date Expire Date
Stability of Gas Atomized Reactive Powders Through Multiple Step In-Situ Passivation Utility United States 13/986,193 9,650,309 4/10/2013 5/16/2017 7/13/2034
Improved Stability of Gas Atomized Reactive Powders Through Multiple Step In-Situ Passivation Divisional United States 15/731,053 10,766,831 4/11/2017 9/8/2020 1/16/2034
Stability of Gas Atomized Reactive Powders Through Multiple Step In-Situ Passivation Divisional United States 15/731,136 10,618,854 4/24/2017 4/14/2020 1/17/2034