The mechanical response of three EB-PVD thermal barrier coating microstructures

The mechanical response of as-received thermal barrier coating specimens wi th three different microstructures was evaluated. Specimens consisted of re ctangular bars of Inconel 617 substrates with NiCoCrAlY bond coats and EB-P VD zirconia top coats. The deposition conditions had been varied to produce columnar top coat microstructures with three different column sizes. Scann ing electron microscopy, optical microscopy, and X-ray diffraction analyses were used to characterize the microstructures. Four-point bend experiments were performed with the top coat under either tension or compression. In s itu microscopy identified the damage formation and propagation modes, and a coustic emission analyses also identified differences in the responses of e ach microstructure. (C) 2000 Elsevier Science S.A. All rights reserved.