The response of ZrB2 to simulated plasma-facing material conditions of He irradiation at high temperature

Zirconium diboride (ZrB2) has many potentially beneficial properties for fusion plasma-facing component application, but almost no data exist on the response of ZrB2 to ion irradiation. In this work, ZrB2 samples were irradiated with 30 keV He+ to fluences of 8.4 × 1021 and 5.0 × 1022 He/m2 at temperatures of 920, 1020, and 1120 K in the Materials Irradiation Experiment (MITE-E) at the University of Wisconsin Inertial Electrostatic Confinement (UW-IEC) Laboratory to simulate some of the conditions of plasma-facing components in fusion reactors. The samples irradiated to the higher fluence developed surface morphology changes in the ion irradiated zone including rough, porous, and ripple structures. The ZrB2 had similar mass loss as W irradiated to similar conditions. Additionally, the ZrB2 samples did not exhibit flaking as did the SiC samples previously irradiated to similar conditions. This first look at ZrB2 behavior under ion irradiation is promising and justifies further testing of this emerging ultra-high temperature ceramic material for fusion applications.