44. exploring the fundamental behavior of tailored nanoscale carbide morphologies: materials by design for ultra-high temperature applications

Department: Mechanical & Aerospace Engineering
Research Institute Affiliation: CaliBaja Center for Resilient Materials & Systems
Faculty Advisor(s): Olivia A. Graeve

Primary Student
Name: Tianqi Ren
Email: tren@ucsd.edu
Phone: 217-898-8771
Grad Year: 2018

Abstract
Many of the Group IV transition metal carbides such as tantalum carbide (TaC), hafnium carbide (HfC), zirconium carbide (ZrC), and niobium carbide (NbC) are classified as ultra-high temperature ceramics (UHTCs) due to their high melting temperatures (typically greater than 3300 K). These UHTCs have drawn increasing attention for aerospace applications such as hypersonic vehicles and scramjets due to their excellent thermo-mechanical properties. In this project, we are exploring the possibility of controlling the particle morphology of transition metal carbides through dopant incorporation. TaC doped with iron (TaC:Fe), nickel (TaC:Ni), cobalt (TaC:Co) and nickel/titanium (TaC:Ni:Ti) is currently being investigated. Powder samples have been synthesized using a solvothermal method, resulting in average particle sizes less than 200 nm. We have observed highly-faceted particles enclosed by {111} and {100} surfaces, as well as cubes in all doped samples under scanning electron microscopy (SEM). TaC:Fe and TaC:Ni:Ti systems have the highest percentage of particle modification. We believe that the dopants investigated modify the morphology of TaC particles by changing the surface energies and thus the relative growth rate among the surfaces.

Industry Application Area(s)
Aerospace, Defense, Security | Materials

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