Developments in r.f. plasma-assisted physical vapour deposition partially yttria-stabilized zirconia thermal barrier coatings

In this paper we initially trace the development of zirconia-based thermal barrier coatings and discuss the rationale for their deposition by plasma-assisted physical vapour deposition. The early experiments to verify the feasibility of this technique are then summarized, with particular reference to surface roughness and microhardness data. Preliminary thermal cycling trials indicate that optimum performance is achieved using a mixed deposition approach. An analysis is also presented to describe the variation in thickness uniformity within the deposition chamber.