A polymer precursor route to metal borides
- Univ. of Pennsylvania, Philadelphia, PA (United States)
A synthetic route to metal borides that employs processable polymer/metal-oxide precursors is described. The precursor materials are obtained by dispersing metal oxides in the decaborane-dicyanopentane polymer, ([minus]B[sub 10]H[sub 12]NC-(CH[sub 2])[sub 5]-CN-)[sub x]. Subsequent pyrolyses of the dispersions above 1400[degrees]C afford metal borides, including TiB[sub 2], ZrB[sub 2], HfB[sub 2], NbB[sub 2], and TaB[sub 2] in high chemical and ceramic yields. The metal boride powders were found to be highly crystalline with grain sizes dependent on processing temperatures. The ceramic conversion reactions are proposed to involve in situ generation of amphorous BCN materials, followed by solid-state reduction of the metal oxides to produce the final boride products. Precursor dispersions formed from submicron metal oxides, along with a suitable surfactant, can be used to generate an emulsion from which metal boride coatings on graphite plates can be obtained. 17 refs., 16 figs., 3 tabs.
- OSTI ID:
- 5036011
- Journal Information:
- Chemistry of Materials; (United States), Journal Name: Chemistry of Materials; (United States) Vol. 5:11; ISSN CMATEX; ISSN 0897-4756
- Country of Publication:
- United States
- Language:
- English
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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
BORIDES
BORON COMPOUNDS
CERAMICS
CHEMICAL ANALYSIS
CHEMICAL PREPARATION
COHERENT SCATTERING
DIFFRACTION
ELECTRON MICROSCOPY
GRAVIMETRIC ANALYSIS
HAFNIUM BORIDES
HAFNIUM COMPOUNDS
MICROSCOPY
NIOBIUM BORIDES
NIOBIUM COMPOUNDS
QUANTITATIVE CHEMICAL ANALYSIS
REFRACTORY METAL COMPOUNDS
SCATTERING
SYNTHESIS
TANTALUM BORIDES
TANTALUM COMPOUNDS
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
TITANIUM BORIDES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
ZIRCONIUM BORIDES
ZIRCONIUM COMPOUNDS