Citation:
R.G. Wellman, A. Scrivani, G. Rizzi, A. Weisenburger, F.H. Tenailleau and J.R. Nicholls, Pulsed electron beam treatment of MCrAlY bondcoats for EB PVD TBC systems part 2 of 2: Cyclic oxidation of the coatings, Surface and Coatings Technology, Volume 202, Issues 4-7, ICMCTF 2007, 34th International Conference and Metallurgical Coatings and Thin Films (ICMCTF 2007), 15 December 2007, Pages 709-713.
Abstract:
This paper discusses the effect of pulsed electron beam (PEB) treatment of
thermal sprayed MCrAlY bondcoats on the cyclic life of thermal barrier coatings
(TBCs). Standard MCrAlY bondcoats were produced via HVOF, VPS and LPPS thermal
spray methods. Some of the HVOF and VPS coatings were then given a PEB treatment
before all the samples were coated with an EB PVD 7-8 wt.% yttria partially
stabilized zirconia topcoat. The samples were all tested under cyclic oxidation
conditions at 1150 à °C with 1 h at temperature and 15 min cooling, samples were
removed after 20% coating spallation and prepared for cross sectional analyses.
Cyclic testing revealed that although the PEB treatment had no measurable effect
on the VPS sprayed samples, the HVOF coatings showed a significant increase in
the cyclic life after the PEB treatment. The effect of the PEB treatment on the
various samples is discussed as well as its effect on TGO growth morphology. PEB
treatment of the HVOF bondcoat was found to reduce the rate of alumina growth
and to suppress the formation of oxide pegs resulting in a smoother bondcoat
interface
