Improving The Environmental Stability Of E-Beam Coatings By Employing A Piad Capping Layer

The properties of coatings deposited by electronic beam (e-beam) technique can be easily influenced by environmental humidity, causing spectrum shift, residual stress evolution, and wave front errors. In this work, HfO2/SiO2 multilayer coatings with different overcoat layer deposition process were prepared. The optical spectrum shift caused by atmosphere-vacuum effect of the prepared samples was investigated by spectrometer. The laser-induced damage resistance was studied and the damage morphologies were characterized by Scanning Electron Microscope (SEM). The surface morphology and global coating stress of the films were analyzed by Atomic Force Microscope (AFM) and Zygo interferometer, respectively. The experimental results demonstrate that by a capping SiO2 layer employed by plasma ion assisted deposition (PIAD), considerable stability concerning the environmental stability of e-beam coatings can be improved due to delayed water vapor transport rate. A relatively smaller grain size can be obtained as well. Moreover, the laser-induced damage threshold (LIDT) shows no significant differences.