Ionization assisted physical vapor deposition of zirconia thermal barrier coatings

Yttria stabilized zirconia has been deposited by electron beam physical vapor deposition under a range of process conditions. The influence of rf plasma assistance, pressure, surface finish, and source to substrate distance on structure, phase, uniformity, and adhesion has been studied. Coatings were found to be predominantly cubic; their texture could be modified by plasma assistance. Also plasma assistance was found to improve adhesion, permit control of coating structure and densification, and provide the possibility to increase pressures, to improve coating thickness uniformity without loss of structure control. Excellent adhesion was obtained even on polished substrates at low temperatures (400 C), which when coupled with the fact that the coating tends to replicate the original surface finish, suggests that good aerodynamic efficiencies and performance should be achieved with thermal barrier coatings produced by this method.