Like many FeCrAl-based alloys, and some MAX phases, the atomically laminated boride, MoAlB, forms slow-growing, adherent Al2O3 scales when heated in air to 1350 degrees C. Herein the oxidation of MoAlB ceramics in air was studied in the 1100-1400 degrees C temperature range for up to 200 h. At 1400 degrees C, the oxide scale was heavily cracked and spalled. At 1100 degrees C, and up to 20 h, mass loss was recorded. At 1300 degrees C and 1350 degrees C, subparabolic, approximately cubic kinetics were observed, as a result of growth and coarsening of the Al2O3 grains in the oxide scale. At 1200 degrees C, the weight gain kinetics were nearly linear, while the oxide thickening kinetics were approximately cubic likely due to cubic growth of Al2O3 and concurrent volatility of constituents in the oxide scale. The cyclic oxidation resistance was also good for up to 125, 1-hour, cycles at 1200 degrees C. Analysis of grain coarsening and scale thickening kinetics suggest that oxygen grain boundary diffusivity is the rate controlling mechanism for the growth of Al2O3 scales at 1300 degrees C and 1350 degrees C. Dimensional changes at samples' corners after long oxidation at T > 1200 degrees C may limit the maximum operational temperature of MoAlB. (c) The Author(s) 2017. Published by ECS. All rights reserved.
Isothermal and Cyclic Oxidation of MoAlB in Air from 1100 degrees C to 1400 degrees C
Creators
Sankalp Kota - Drexel University
Eugenio Zapata-Solvas - Imperial College London
Yexiao Chen - Texas A&M University
Miladin Radovic - Texas A&M University
William E. Lee - Imperial College London
Michel W. Barsoum - Drexel University
Publication Details
Journal of the Electrochemical Society, v 164(13), pp C930-C938
Publisher
Electrochemical Soc Inc
Number of pages
9
Grant note
EP/M018563/1; EP/M018768/1 / EPSRC; UK Research & Innovation (UKRI); Engineering & Physical Sciences Research Council (EPSRC)
1410983 / Direct For Mathematical & Physical Scien; National Science Foundation (NSF); NSF - Directorate for Mathematical & Physical Sciences (MPS)
EP/K008749/2 / Engineering and Physical Sciences Research Council; UK Research & Innovation (UKRI); Engineering & Physical Sciences Research Council (EPSRC)
EP/K008749/1 / EPSRC; UK Research & Innovation (UKRI); Engineering & Physical Sciences Research Council (EPSRC)
1729335; 1729350 / CMMI division of NSF
DMR-1410983 / NSF; National Science Foundation (NSF)
Resource Type
Journal article
Language
English
Academic Unit
Materials Science and Engineering
Web of Science ID
WOS:000418409800109
Scopus ID
2-s2.0-85034428571
Other Identifier
991019167959704721
InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool: