159. effect of electric current on densification mechanism of zirconium nitride consolidated by spark plasma sintering

Department: Mechanical & Aerospace Engineering
Faculty Advisor(s): Eugene Olevsky | Joanna M. McKittrick

Primary Student
Name: Geuntak Lee
Email: gel003@ucsd.edu
Phone: 858-534-5425
Grad Year: 2017

The densification mechanism of zirconium nitride (ZrN) powder at the intermediate stage of the consolidation process (i.e. for 72% < relative density < 92%) is revealed by comparing the electric current-assisted spark plasma sintering (SPS) with non-electric-current assisted hot pressing (HP) carried out under the same pressure and temperature experimental conditions. In order to determine the real temperature inside ZrN powder, a sacrificial thermocouple is directly inserted into the powder during the SPS process. The spatial distribution of the electric current passing through the powder is calculated using the finite element modeling. The porosity-interparticle neck area geometrical relationship is applied to estimate the electric current density inside the powder volume subjected to SPS. For taking into account (for the first time ever) the explicit influence of the electric current effect on the SPS densification mechanism, the constitutive equations describing hot pressing are modified. Thereby the densification mechanism of ZrN is revealed by the inverse regression of the new SPS constitutive equations and by utilizing the experimental results on ZrN consolidation with and without the participation of the electric current effect.

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

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