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Oxidation Kinetics and Mechanisms of Hot‐Pressed TiB 2 –MoSi 2 Composites
Author(s) -
Raju Golla Brahma,
Basu Bikramjit,
Suri Ashok Kumar
Publication year - 2008
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2008.02656.x
Subject(s) - materials science , isothermal process , rutile , sintering , oxide , thermogravimetric analysis , kinetics , titanium diboride , composite material , dilatometer , ceramic , microstructure , hot pressing , metallurgy , chemical engineering , thermal expansion , physics , quantum mechanics , engineering , thermodynamics
The densification of titanium diboride (TiB 2 ) at lower sintering temperature requires the use of sinter‐aid. However, from the high temperature application point of view, it is important to assess whether the presence of sinter‐aid degrades the material properties, including the oxidation resistance. In the present work, the isothermal oxidation behavior of TiB 2 ‐ x wt% MoSi 2 ( x =0, 2.5, and 10) composites was carried out using thermogravimetric analyzer in order to study the effect of MoSi 2 content on the oxidation kinetics of TiB 2 at 1200°C for a duration of 12 h. The oxidized surface of monolithic TiB 2 composed of highly textured rod‐like rutile (TiO 2 ) crystals. In contrast, the oxide scales on TiB 2 –MoSi 2 materials consist of a thin layer of SiO 2 along with TiO 2 . Interestingly, the analysis of the continuous measurements of the weight gain reveals parabolic rate law of oxidation for all the investigated ceramics. However, the oxidation kinetics is slower for the TiB 2 ‐10 wt% MoSi 2 , probably due to the presence of SiO 2 in the oxide scale.