Carbothermal nitridation of solution synthesised ZrO2-carbon nanocomposites; phase-development from precursor to nitride

• A carbothermal nitridation route to nanophase ZrN1-xCx powder using nitrogen gas and a highly homogeneous solution derived carbon-ZrO2 nanocomposite is described. Composites with 2-4 nm sized ZrO2 particles were prepared by hydrolysis of Zr(OPrn)(4) and sucrose with 2-8 sucrose-C:Zr and heating to 600 degrees C. The phase-evolution on heating was elucidated in detail using: TG-DTA, XRD, XPS, IR- and Raman spectroscopy, SEM-EDS, and TEM-EDS. With 5-8 C:Zr samples heated to 1495 degrees C, somewhat agglomerated single-crystalline Zr (N,C) particles in sizes centred around 40-90 nm were obtained, in some cases with minor amounts of r-Zr7O8N4 and m-ZrO2. The c-Zr(N,C) had slightly larger XRD cell-dimensions (a = 4.589-4.606 angstrom) than the literature ZrN (a = 4.5775 A), due to some carbon substitution in the nitrogen positions. The single-crystalline Zr(N,C) particle cores of the 8C:Zr, and to some extent 7C:Zr, samples, had a 4-6 nm thick distinctive amorphous or microcrystalline Zr(N,C,O) shell.

Ämnesord

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Materials Chemistry (hsv//eng)

Nyckelord

ZrN

Carbothermal nitridation

Nano-phase powder

Core-shell particles

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