空気アトマイズ法によるマグネシウム合金粉末製作の検討

抄録

We investigated the possibility of atomizing molten magnesium (Mg) alloy by air instead of argon gas in order to manufacture the powder at low cost. As a result, we obtained the powder from molten Mg alloy containing yttrium (Y), calcium (Ca) or aluminium (Al) by air atomization without combustion. Each powder had approximately 100 nm thick oxide film with condensed Y, Ca or Al, which could make the oxide film dense enough to isolate the molten Mg alloy droplet surface from air. In the case of Al, 6 mass% Al or more was required to prevent combustion. Al was also condensed in the matrix near the interface with oxide film, which could reduce the Mg vapor pressure on the matrix surface under the oxide film. High cooling rate of droplet is also effective to prevent combustion. As air atomized AZX912 powder has the same matrix structures as argon gas atomized one, we expect that the sintered parts of air atomized Mg alloy powder can be obtained by breaking the oxide film in the forming process.