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This content will become publicly available on March 8, 2017

Title: MoSi 2 Oxidation in 670-1498 K Water Vapor

Molybdenum disilicide (MoSi2) has well documented oxidation resistance at high temperature (T > 1273 K) in dry O2 containing atmospheres due to the formation of a passive SiO2 surface layer. But, its behavior under atmospheres where water vapor is the dominant species has received far less attention. Oxidation testing of MoSi2 was performed at temperatures ranging from 670–1498 K in both 75% water vapor and synthetic air (Ar-O2, 80%–20%) containing atmospheres. Here the thermogravimetric and microscopy data describing these phenomena are presented. Over the temperature range investigated, MoSi2 displays more mass gain in water vapor than in air. The oxidation kinetics observed in water vapor differ from that of the air samples. Two volatile oxides, MoO2(OH)2 and Si(OH)4, are thought to be the species responsible for the varied kinetics, at 670–877 K and at 1498 K, respectively. Finally, we observed an increase in oxidation (140–300 mg/cm2) from 980–1084 K in water vapor, where passivation is observed in air.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;
  1. Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos New Mexico
  2. Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos New Mexico; Department of Nuclear Engineering, University of California, Berkeley, Berkeley California
Publication Date:
OSTI Identifier:
1259968
Report Number(s):
LA-UR--15-26638
Journal ID: ISSN 0002-7820
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Journal of the American Ceramic Society
Additional Journal Information:
Journal Volume: 99; Journal Issue: 4; Journal ID: ISSN 0002-7820
Publisher:
American Ceramic Society
Research Org:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS MoSi₂; Nuclear Fuel Cladding; Steam Oxidation