ChemInform Abstract: Formation of NbC and TaC from Gel-Derived Precursors.

✍ Scribed by H. PREISS; D. SCHULTZE; P. KLOBES

• Publisher: John Wiley and Sons
• Year: 2010
• Weight: 30 KB
• Volume: 29
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.199808012

✦ Synopsis

Formation of NbC and TaC from Gel-Derived Precursors.

-The title carbides with grain sizes of ¡ 1 µm and intercrystalline porosity are prepared at 1400-1500 • C by a sol-gel technique using binary organic-inorganic gels as precursors for the carbothermal reduction. The gels are prepared from sols of the transition metal alkoxides or peroxo acids and carbonaceous gel or saccharose. Pyrolysis at 600-700 • C yields precursors consisting of nanometer sized oxide particles in a carbon matrix which can be reduced carbothermally at lower temp. than physical mixtures of oxides with carbon. The change from poreless to microporous gels via mesoporous intermediates to the title carbides are studied by XRD, TG/DTA, and nitrogen absorption experiments.