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Title: Reactions of metal chlorides with hexamethyldisilazane: Novel precursors to aluminum nitride and beyond
Metal nitrides are intensely investigated because they can offer high melting points, excellent corrosion resistance, high hardness, electronic and magnetic properties superior to the corresponding metals/metal oxides. Thus, they are used in diverse applications including refractory materials, semiconductors, elec- tronic devices, and energy storage/conversion systems. Here, we present a sim- ple, novel, scalable and general route to metal nitride precursors by reactions of metal chlorides with hexamethyldisilazane [HMDS, (Me3 Si)2 NH] in tetrahydro- furan or acetonitrile at low temperatures (ambient to 60◦C/N2). Such reactions have received scant attention in the literature. The work reported here focuses primarily on the Al-HMDS precursor pro- duced from the reaction of AlCl3 with HMDS (mole ratio = 1:3) characterized by matrix-assisted laser desorption/ionization-time of flight, Fourier-transform infrared spectroscopy, thermogravimetric analysis-differential thermal analysis, and multinuclear nuclear magnetic resonance spectroscopy (NMRs) for chemi- cal and structural analyses. The Al-HMDS precursor heated to 1600◦C/4 h/N2 produces aluminum nitride, characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy/energy-dispersive X- ray spectroscopy, and magic-angle spinning NMR. On heating to 800–1200◦C/4 h/N2, the precursor transforms to an amorphous, oxygen-sensitive powder with very high surface areas (>200 m2/g) indicating nanosized particles, which can be used as additives to polymer matrices to modify their thermal stabilities. Al2O3 is also presented in the final product after heating, due to its high susceptibility to oxidation. This approach was extended via proof-of-concept studies to other metal chloride systems, including Zn-HMDS, Cu-HMDS, Fe-HMDS, and Bi-HMDS. The formed precursors are volatile, offering the potential utility as gas-phase deposition pre- cursors for their corresponding metal nitrides.  more » « less
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Journal of the American Ceramic Society
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Medium: X
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National Science Foundation
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