Liquid Borane Precursors for the Deposition of Zirconium and Hafnium Diboride
Abstract
The purpose of this basic research is to develop liquid-phase boron sources for the chemical vapor deposition (CVD) of zirconium- and hafnium diboride. ZrB2 and HfB2 are ultrahigh-temperature ceramics that have drawn attention as thermo-protective coatings for hypersonic flight and atmospheric re-entry. Both materials have normal melting points above 3200 C, and both are essentially impervious to oxidation. CVD of films of these compounds remains difficult, especially onto such irregular substrates as silicon carbide fibers. A continuing challenge is identification of boron sources that are liquids at ambient laboratory temperature and pressure. Alkyldecaboranes are proposed here as air-stable liquid reagents for the CVD of metal borides. Chemical reactions of alkyl- and alkenyldecaboranes with zirconium(IV) and hafnium(IV) reagents are described here, both to discover new CVD precursors and to understand the structure and thermodynamics of reactive intermediates in vapor deposition. Also proposed are computational studies to establish structure-property relationships of liquid alkyldecaboranes.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jun 09, 2021
- Source ID
- N000142112230
Entities
People
- Thomas G Gray
Organizations
- Case Western Reserve University
- Office of Naval Research
- United States Navy