Research Area 11.1 Short-Term Innovative Research (STIR) Program: Tailored Carbide Morphologies: Materials by Design for Creep Resistance at Ultra-high Temperatures
Abstract
Transition metal carbide (TMC) powders including TaC and ZrC with less than 300 nm in particle size have been successfully synthesized by a unique solvothermal approach. We have effectively modified the particle morphology of the TMC particles from round/irregular shapes to polyhedrons enclosed by {111} and {100} surfaces. We also report the formation of perfect/truncated nanocubes through the dual-effects of carbide diluent and transition metal doping. The TaC:Ni system demonstrated ~80% of morphological modification among the particles evaluated. The governing mechanisms for Ni to have significant impact on morphological modification include (1) the selective absorption of Ni atoms onto {100} surfaces and (2) the molten Ni acts as diluent for carbon dissolution and diffusion. The effectiveness of the carbide diluent is attributed to its lowering of the maximum combustion temperature during reaction, which prevents particle surfaces from roughening and rounding, promoting exposure of facets.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 04, 2018
- Source ID
- W911NF1610585
Entities
People
- Olivia A Graeve
Organizations
- Army Contracting Command
- United States Army
- University of California, San Diego