Oxidation kinetics of magnesium aluminum oxynitride-boron nitride (MgAlON-BN) composites
2014 (English)In: Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi/Journal of the Ceramic Society of Japan, ISSN 1882-0743, Vol. 122, no 1429, 829-834 p.Article in journal (Refereed) Published
The oxidation behaviour of MgAlON-BN composite was investigated under the air atmosphere using thermogravimetry (TG), scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques in the present articles. Non-isothermal experimental results indicated that the rate of oxidation can be neglected at low temperature and, with further increasing temperatures, an increase of the oxidation was observed. While BN addition promoted the oxidation above 1100 K, and the weight gain was observed to decrease due to the fast evaporation of boron oxide as the temperature was beyond 1580 K. Isothermal studies also clearly indicated the decrease of weight gain due to evaporation after a certain oxidation time. The oxidation mechanism was investigated, and the results showed the oxidation products were gamma-Al2O3 at low temperature and transformed to alpha-Al2O3 as the temperature was above 1100 degrees C. BN addition promoted the transformation from gamma-Al2O3 to alpha-Al2O3. From the isothermal oxidations, the kinetics of oxidation and evaporation were evaluated, and the overall kinetics of oxidation and evaporation were studied, and the activation energy for evaporation of B2O3 and for the oxidation of MgAlON-15 vol% BN at the later stage are 115.4 and 196.1 kJ/mol, respectively. The present paper provides a way to deal with oxidation of composites containing evaporating component.
Place, publisher, year, edition, pages
2014. Vol. 122, no 1429, 829-834 p.
Magnesium aluminum oxynitride, Boron nitride, Thermogravimetry, Oxidation, Activation energy
IdentifiersURN: urn:nbn:se:kth:diva-154388DOI: 10.2109/jcersj2.122.829ISI: 000342066500016ScopusID: 2-s2.0-84906965696OAI: oai:DiVA.org:kth-154388DiVA: diva2:756962
QC 201410202014-10-202014-10-202014-10-20Bibliographically approved