• Title/Summary/Keyword: prcipitates

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Effects of Te on the Anti-Galling Properties of Ni-Cr-Sn-Bi Alloy (Ni-Cr-Sn-Bi합금의 anti-galling 특성에 미치는 Te의 영향)

  • Ha Heon-Phil;Kim Kyung-Tak;Shim Jae Dong;Kim Yong Kyu
    • Korean Journal of Materials Research
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    • v.15 no.1
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    • pp.14-18
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    • 2005
  • Ni-Cr-Sn-Bi alloys were prepared by air melting and sand casting method and their anti-galling behaviors were examined. Anti-galling properties were dominantly influenced by Bi-rich low temperature precipitates. Alloying effects on the anti-galling properties were investigated for several alloying elements to improve anti-galling properties of the alloy. An alloy with $1-3wt\%$ of Te showed markedly improved anti-galling properties. Metallographic and tribological tests were carried out to find out reasons for excellent properties. It was found that Te containing alloy has finely distributed precipitates of Bi-rich phase. The addition of Te changed the morphology of the Ni-rich primary phase from globular to fine dendritic. As a result, the anti-galling phase precipitated between dendrite arms with fine distribution showed excellent anti-galling properties.