Enhanced oxidation resistance of Mo–Si–B–Ti alloys by pack cementation

Daniel Schliephake, Camelia Gombola, Alexander Kauffmann, Martin Heilmaier, John H. Perepezko

Research output: Contribution to journalArticleResearchpeer-review

13 Citations (Scopus)

Abstract

As new high-temperature structural materials, Mo–Si–B alloys satisfy several requirements such as oxidation and creep resistance. Recently, novel Ti-rich Mo–Si–B alloys have shown an increased creep resistance compared to Ti-free alloys. However, due to the formation of a duplex SiO2–TiO2 oxide layer, which allows for fast ingress of oxygen, the oxidation resistance is poor. To improve the oxidation resistance, a borosilicate-based coating was applied to a Mo–12.5Si–8.5B–27.5Ti (in at.%) alloy. After co-deposition of Si and B by pack cementation at 1000 °C in Ar, a conditioning anneal at 1400 °C is used to develop an outer borosilicate layer followed by an inner MoSi2 and Mo5Si3 layer. During both isothermal and cyclic oxidation after an initial mass loss during the first hours of exposure, a steady state is reached for times up to 1000 h at temperatures ranging from 800 to 1200 °C, demonstrating a significantly enhanced oxidation resistance.

Original languageEnglish
Pages (from-to)267-277
Number of pages11
JournalOxidation of Metals
Volume88
Issue number3-4
DOIs
Publication statusPublished - 1 Oct 2017
Externally publishedYes

Keywords

  • High-temperature materials
  • Mo–Si–B–Ti alloys
  • Oxidation-resistant coating
  • Pack cementation

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