Laser-assisted plasma coating at atmospheric pressure: production of yttria-stabilized zirconia thermal barriers

Abstract

A laser-assisted plasma-coating technique at atmospheric pressure (LAPCAP) has been investigated. The electron temperature, electron density and gas temperature of the atmospheric-pressure plasma have been measured using optical emission spectroscopy (OES). LAPCAP utilizes laser ablation of 3 mol% yttria-stabilized zirconia into an atmospheric helium/nitrogen plasma to deposit thermal barrier coatings on a nickel-based substrate. The deposited film shows columnar structures similar to films prepared by high-vacuum deposition methods, such as physical vapour deposition and conventional pulsed-laser deposition. However, the LAPCAP films have smaller columns and higher porosity, compared with the films deposited by other techniques. The morphology and characteristics of the films have been analysed by scanning electron microscope, focused ion beam and x-ray diffraction.