ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
AlN/Al ceramic composite was fabricated by directed melt nitridation of pure Al block coveredwith 10wt% Mg powder at 1300°C in a high purity flowing N2. Microstructure and phase composition ofthe composite were investigated by scanning electron microscopy with energy dispersive spectroscopyand X-ray diffraction. Results showed that AlN is the main phase in the composite and its lattice parametersof a and c are 3.1110Å and 4.9806Å, respectively. The phase composition of the composite changesalong the growth direction and a gradient sandwich structure forms. The surface of the composite is madeup of a dense and thin nodular AlN layer, underneath which an AlN/Al layer appears, followed by anAlN/Al/MgAl2O4 layer. Thermodynamic calculations predicted the formation of possible phases with theaddition of Mg. It suggested that the content of Mg at the reaction frontier of nitridation is considerablylower to 0.15wt% where MgAl2O4 was stable, because of escape and reaction exhaustion of Mg. Once Mgis lower than 0.05wt%, only a dense AlN layer can exist, which prevents the further nitridation of Al melt
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/56/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.368-372.977.pdf
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