Deoxidation of Titanium Using Mg as Deoxidant in MgCl{sub 2}-YCl{sub 3} Flux

Journal Article · Mon Apr 15 04:00:00 EDT 2019 · Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science

DOI:https://doi.org/10.1007/S11663-018-1494-2· OSTI ID:22933668

Zheng, Chenyi; Ouchi, Takanari; Iizuka, Akihiro; Taninouchi, Yu-ki; Okabe, Toru H. ^[1]

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1. The University of Tokyo, Institute of Industrial Science (Japan)

To reduce the oxygen level in titanium (Ti) to less than 1000 mass ppm O, using magnesium as the deoxidant at 1300 K (1027 °C), the activity of the deoxidation product (MgO), i.e., a{sub MgO}, in the system must be reduced to less than 0.04, from a thermodynamic viewpoint. In this study, we developed a new deoxidation technique for Ti, by adding yttrium chloride (YCl{sub 3}) to magnesium chloride (MgCl{sub 2}) flux, which effectively decreases and maintains the a{sub MgO} in the system at a low level, via the formation of yttrium oxychloride (YOCl). Through thermodynamic assessment using a p{sub O{sub 2}}-p{sub Cl{sub 2}} diagram, as well as experiments, the deoxidation of Ti to an oxygen level below 1000 mass ppm O, via the reaction O (in Ti) + Mg + YCl{sub 3} → MgCl{sub 2} + YOCl, was confirmed. Furthermore, using the E-pO{sup 2−} diagram of the M-O-Cl system (M = Y, Mg), the possibility of electrochemical deoxidation is discussed. In the MgCl{sub 2}-YCl{sub 3} flux, Mg deposits on the Ti cathode and simultaneously deoxidizes it. The activity of the deoxidation product, MgO, decreases due to the formation of YOCl and/or the electrochemical oxidation of oxide ions on the carbon anode; thus, the deoxidation of Ti becomes feasible. This new deoxidation technique using rare-earth-containing MgCl{sub 2} flux can be applied to the recycling of Ti scraps, in the future.

• OSTI ID: 22933668
• Journal Information: Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science, Journal Name: Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science Journal Issue: 2 Vol. 50; ISSN MTBSEO; ISSN 1073-5615
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANODES
CARBON
CATHODES
DIAGRAMS
ELECTROCHEMISTRY
MAGNESIUM
MAGNESIUM CHLORIDES
MAGNESIUM OXIDES
OXIDATION
OXYCHLORIDES
OXYGEN
RARE EARTHS
RECYCLING
REDUCTION
THERMODYNAMICS
TITANIUM
YTTRIUM CHLORIDES