Oxidation Behavior of Magnesium Aluminum Oxynitride with Different Composition

Abstract

Oxidation behavior of spark plasma sintered SPS magnesium aluminum oxynitride MgAlON with different composition was investigated in present work. Results showed that the variation in composition had not obvious effect on the density of MgAlON, but had some effect on excess weight change. Also found that the oxidation behavior of MgAlON was different with oxidation temperature, which was attributed to the transformation from g-Al 2 O 3 to a-Al 2 O 3 . Moreover, the excess weight change was ascribed to the existence of lots of vacancies in g-Al 2 O 3 and magnesium aluminate spinel MgAl 2 O 4 ss .

Synthesis and Oxidation Behavior of MgAlON Prepared from Different Starting Materials

“…It can be seen that the complete oxidation temperature of MgAlON prepared by different approaches with high‐purity raw materials is about 1300°C 13,14 . In contrast, MgAlON prepared with high‐purity raw materials in this work was completely oxidized at 1500°C.…”

“…The overall oxidation behavior of MgAlON follows 8 MgAlON+O 2 →MgAl 2 O 4SS +Al 2 O 3 +N 2 . It was also observed 13 that variation in the composition of the MgAlON solid solution did not exert a noticeable influence on the onset oxidation temperature and the temperature at which α‐Al 2 O 3 began to appear.…”

“…Therefore, there has been increased interest in the oxidation behaviors of MgAlON in recent years. It was found that oxidation of MgAlON powder started at about 750°C, 8,11 even if the oxidation rate of MgAlON was very slow below 1000°C 13 . Although the oxidation rate increased dramatically above 1000°C from the mass gain results of the MgAlON oxidation test, X‐ray powder diffractometry (XRD) results showed that only monolithic MgAlON was observed at different oxidation temperatures up to 1100°C 13 .…”

“…It was found that oxidation of MgAlON powder started at about 750°C, 8,11 even if the oxidation rate of MgAlON was very slow below 1000°C 13 . Although the oxidation rate increased dramatically above 1000°C from the mass gain results of the MgAlON oxidation test, X‐ray powder diffractometry (XRD) results showed that only monolithic MgAlON was observed at different oxidation temperatures up to 1100°C 13 . Only at 1200°C or above, was another phase of α‐Al 2 O 3 detected in the oxidized product besides the cubic spinel crystalline phase 13,14 .…”

“…Although the oxidation rate increased dramatically above 1000°C from the mass gain results of the MgAlON oxidation test, X‐ray powder diffractometry (XRD) results showed that only monolithic MgAlON was observed at different oxidation temperatures up to 1100°C 13 . Only at 1200°C or above, was another phase of α‐Al 2 O 3 detected in the oxidized product besides the cubic spinel crystalline phase 13,14 . The overall oxidation behavior of MgAlON follows 8 MgAlON+O 2 →MgAl 2 O 4SS +Al 2 O 3 +N 2 .…”