Surface analysis of VPS-W coatings boronized by an ICRF discharge in HT-7

To understand the surface compositions and the hydrogen isotope behavior in boronized Vacuum plasma spraying (VPS)-W, the boron coating has been achieved by means of Ion Cyclotron Radio Frequency (ICRF) boronization using carborane (C2B10H12) powder as the precursor material in HT-7. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) were used to observe the morphology of the VPS-W and boronized W surfaces. The X-ray Photoelectron Spectroscopy (XPS) of W-4f, O-1s, C-1s and B-1s on the VPS-W sample before and after boronization and after plasma exposure have been measured. The B–B and B–C bonds were observed after boronization treatment for VPS-W. Thermal Desorption Spectroscopy (TDS) experiments were also carried out to investigate the thermal desorption behavior of D implanted into the samples. After HT-7 plasma exposure, the desorption spectrum had a low temperature peak associated with trapping in intrinsic defects in polycrystalline W and a high temperature peak associated with B–O–D and B–C–D bonds.