Effect of Ba deoxidation on oxygen content in NiTi alloys and non-metallic inclusions

Daisuke Ito, Naruhiko Nishiwaki, Kyosuke Ueda, Takayuki Narushima

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7 Citations (Scopus)


The effect of Ba deoxidation on the oxygen content and non-metallic inclusions in NiTi alloys was investigated. The NiTi alloy melt was held in a CaO crucible at 1673 K under Ar gas flow for 0-600 s. Metallic Ba (0.5-1.5 mass% with respect to NiTi alloy melt) was added to the melt. After melting, oxygen content of 710 and 330 mass ppm decreased to 210 and 130 mass ppm, respectively, after a holding time of 300 s after the addition of Ba. The oxygen in the melts was reduced to as low as 64 mass ppm after a second Ba deoxidation. The non-metallic inclusions observed in the NiTi alloys were the Ti 4Ni2O X and Ti(C,N,O) X types. Decreased oxygen content through Ba deoxidation caused a change in the main phase of the non-metallic inclusions from the Ti4Ni2O X type to the Ti(C,N,O) X type, and a decrease in the area percents of the non-metallic inclusions.

Original languageEnglish
Pages (from-to)359-366
Number of pages8
JournalJournal of Materials Science
Issue number1
Publication statusPublished - 2013 Jan


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