Effect of SF₆ Concentrations on Protective Film of Vacuum Counter-Pressure Filling Molten Magnesium Alloy

Abstract:

Through testing and analyzing Surface micromorphology of protective film and elemental composition and content of vacuum counter-pressure filling AZ91D magnesium alloy by SF₆ mixed gas, the effect of SF₆ concentrations on protective film of vacuum counter-pressure filling molten magnesium alloy was studied. The results show that SF₆ concentrations have greater effect on protective film of molten magnesium alloy. With the increase of SF₆ concentrations, surface micromorphology of protective filmof vacuum counter-pressure filling AZ91D magnesium alloy becomes more continuous and dense. Meanwhile, the mass fraction of F atom of the protective film is increased, and the content of O atom is decreased. Moreover, F/O atomic ratio increases significantly too, so MgF₂ content of the protective film increases gradually. Therefore, protective effect of molten magnesium depends on F/O atomic ratio and MgF₂ content of the protective film. When SF₆ concentrations are greater than 4.8 , protective effect of molten magnesium is good.

• Periodical: Advanced Materials Research (Volumes 785-786)
• Pages: 1027-1030
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.785-786.1027
• Online since: September 2013
• Authors: Qing Song Yan*, Yang Zhen, Bo Wen Xiong, Gang Lu, Bai Ping Lu
• Keywords: Magnesium Alloy, Protective Film, SF₆ Concentrations, Vacuum Counter-Pressure Casting

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