High temperature oxidation behavior of Al added Mo / Mo5SiB 2 in-situ composites

Akira Yamauchi, Kyousuke Yoshimi, Shuji Hanada

Research output: Contribution to journalConference articlepeer-review

2 Citations (Scopus)


Isothermal oxidation behavior of Mo/Mo5SiB2 in-situ composites containing small amounts of Al was investigated under an Ar-20%O 2 atmosphere in the temperature range of 1073-1673 K. The Mo/Mo 5SiB2 in-situ composites, (Mo-8.7mol%Si-17.4mol%B) 100-xAlx (x=0, 1, 3, and 5mol%), were prepared by Ar arc-melting, and then homogenized at 2073 K for 24 h in an Ar-flow atmosphere. Without addition of Al, Mo/Mo5SiB2 in-situ composite exhibits a rapid mass loss at the initial oxidation stage, followed by passive oxidation after the substrate is sealed with borosilicate glass in the temperature range of 1173-1473 K, whereas it exhibits a rapid mass gain around 1073 K. On the other hand, small Al additions, especially of 1 mol%, significantly improve the oxidation resistance of Mo/Mo5SiB 2 in-situ composites at temperatures from 1073-1573 K. The excellent oxidation resistance is considered to be due to the rapid formation of a continuous, dense scale of Al-Si-O complex oxides. The protective oxide scales contain crystalline oxides, and the amounts of the crystalline oxides obviously increase with Al concentration.

Original languageEnglish
Article numberS5.34
Pages (from-to)315-320
Number of pages6
JournalMaterials Research Society Symposium Proceedings
Publication statusPublished - 2005
Event2004 MRS Fall Meeting - Boston, MA, United States
Duration: 2004 Nov 292004 Dec 1


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