Location

Pettit Microelectronics Building Room 102A and/or virtually via MS Teams

Isabella Stepanek
Advisor: Prof. Eric Vogel


will propose a doctoral thesis entitled,


Low temperature synthesis of MAX-phase Ti2AlC coatings and their performance as hydrogen isotope permeation barriers for fusion technologies


On


Monday, October 12 at 12 p.m.
Pettit Microelectronics Building Room 102A

and/or virtually via MS Teams

 

Abstract

Realizing practical fusion energy requires materials that can withstand simultaneous neutron irradiation, thermal cycling, and corrosive molten salts without degrading. Conventional barriers such as Al2O3 achieve high reduction factors in laboratory conditions but degrade irreversibly under neutron irradiation and thermal cycling. This work exploits the unique defect tolerance and self-healing behavior of the nanolaminated MAX-phases, specifically Ti2AlC, to address the hydrogen isotope permeation control problem in fusion blanket design. Aim 1 establishes a simplified bilayer synthesis approach combining an aluminum precursor layer with a TiAlC layer, enabling Ti2AlC formation at 650 °C through controlled Al diffusion, reducing the temperature requirements of conventional synthesis while eliminating the per-layer calibration challenges of prior methods. Aim 2 adapts this route to Grade 91 steel, a fusion-relevant structural substrate, and provides the first quantified permeation reduction factors for Ti2AlC-containing coatings through gas-driven deuterium permeation experiments, demonstrating one order of magnitude reduction in hydrogen isotope flux. Aim 3 evaluates barrier durability by measuring coating performance and structure before and after heavy-ion irradiation and molten salt exposure, establishing whether the predicted radiation tolerance and corrosion stability of MAX-phases hold in thin-film form under fusion-relevant conditions. Together, these efforts validate a pathway for engineering MAX-phase permeation barriers on structural materials within realistic fusion reactor thermal budgets.

Committee

  • Prof. Eric Vogel – School of Materials Science and Engineering (advisor)
  • Dr. Dale Hitchcock – Savannah River National Laboratory
  • Prof. Mark Losego – School of Materials Science and Engineering
  • Prof. Caitanya Deo – School of Mechanical Engineering