Synthesis and characterization of MgAlON-BN composites

• In the present paper the Gibbs energy of formation of MgAlON was evaluated, and on this basis the phase stability diagram of Mg-Al-O-N-B was established. Dense magnesium aluminium oxynitride-boron nitride (MgAlON-BN) composites with 0-30 vol.% BN were synthesized by hot pressing in the temperature range 1750-1850 degrees C in the phase stability region. The phase compositions of the composites analyzed by X-ray diffraction indicated that the main phases were MgAlON and h-BN and no impurities were found. The microstructures of the composites analyzed by transmission electron microscopy, scanning electron microscopy, and high-resolution electron microscopy showed that the MgAlON did not react with BN, and the latter was distributed on the grain boundary of MgAlON homogeneously. Excessive BN (> 20 vol.%) resulted in a discontinuous microstructure for MgAlON. A matrix-flushing method was employed in the quantitative X-ray diffraction analysis for the multi-component MgAlON-BN composites. The results showed that the relative MgAlON content decreased in the process of sintering MgAlON-BN composites. Thermodynamic analysis showed that some Al2O3, AlN, and MgO escaped under the reaction conditions. The lattice parameters of MgAlON in the composites have also been evaluated.

Ämnesord

NATURVETENSKAP  -- Data- och informationsvetenskap -- Systemvetenskap, informationssystem och informatik (hsv//swe)

NATURAL SCIENCES  -- Computer and Information Sciences -- Information Systems (hsv//eng)

Nyckelord

MgAlON-BN

thermodynamic analysis

composites

quantitative analysis

Computer and systems science

Data- och systemvetenskap

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