NDE assessment of TBCs: an interim report of a photo-stimulated luminescence ‘round-robin’ test

Nychka, John A.; Clarke, David R.; Sridharan, Swetha; Jordan, Eric H.; Gell, Maurice; Lance, Michael J.; Chunnilall, Christopher J.; Smith, I. M.; Saunders, S. R. J.; Pillan, R; Sergo, Valter; Selçuk, Ahmet; Atkinson, A.; Murphy, K. S.

doi:10.1016/s0257-8972(02)00596-0

Cited by 36 publications

(12 citation statements)

References 6 publications

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“…As a consequence, when undertaking PLPS measurements of stresses within the TGO, lateral spreading of the incident laser beam within the TBC will affect the measurement resolution, which is defined by the diameter of the laser at the TGO surface [35]. This resolution is important, for example, for defining the step size when mapping stress in the TGO through the YSZ layer to avoid overlap of the measurements and thereby provide more reliable stress information [36], [37] and [38]. In this paper, the laser beam spreading and the sampling depth of Raman spectroscopy within the YSZ is investigated.…”

Section: Figmentioning

confidence: 99%

The role of beam dispersion in Raman and photo-stimulated luminescence piezo-spectroscopy of yttria-stabilized zirconia in multi-layered coatings

et al. 2013

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Laser beam dispersion affects the resolution of Raman and photo-stimulated luminescence piezo-spectroscopy measurements of transparent materials. In this paper, we investigate the lateral spreading of the laser beam and the axial sampling depth of Raman spectroscopy measurements within thermal sprayed yttria-stabilized zirconia (YSZ) thin coatings. The lateral diameters of the laser beams (λ = 632.8 nm and 514 nm) reach approximately ∼160 µm after travelling through a thickness of 200 µm of air plasma sprayed (APS) YSZ and ∼80 µm after travelling through 120 µm of electron beam physical vapour deposited YSZ. The Raman spectroscopy sampling depth was found to be between 30 and 40 µm in APS YSZ. The beam dispersions within these two coatings were simulated using the ray-tracing software ZEMAX to understand the observed scattering patterns. The results are discussed with respect to the application of these two spectroscopic techniques in multi-layered thermal barrier coating systems.

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Section: Figmentioning

confidence: 99%

The role of beam dispersion in Raman and photo-stimulated luminescence piezo-spectroscopy of yttria-stabilized zirconia in multi-layered coatings

et al. 2013

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“…The signal intensity is large enough to allow for nondestructive stress measurement from the scale grown under a YSZ (yttria stabilized zirconia) top coat [22]. In this work, PLPS was used to characterize specimens with and without an APS-YSZ top coating to build upon previous work [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

The effect of cycle frequency, H2O and CO2 on TBC lifetime with NiCoCrAlYHfSi bond coatings

Lance

Unocic

Haynes

et al. 2014

Surface and Coatings Technology

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a b s t r a c t a r t i c l e i n f o Available online xxxx Keywords: Photo-stimulated luminescence piezospectroscopy (PLPS) Water vapor Bond coating Alumina scale TBCFurnace cycle testing of superalloy 1483 and X4 substrates with high velocity oxygen fuel (HVOF) NiCoCrAlYHfSi bond coatings and air plasma sprayed (APS) yttria-stabilized zirconia (YSZ) top coatings was conducted at 1100°C in various environments. Average thermal barrier coating (TBC) lifetimes were 5-6 times longer when 100 h cycles were used to simulate base-load power generation operation, compared to the 1 h aero-engine standard cycle. Longer exposure times for 100 h cycles increased the interdiffusion resulting in no clear effects of H 2 O and CO 2 additions on average TBC lifetime for the 1483 substrates, contrary to the results with 1 h cycles where the addition of H 2 O reduced TBC lifetime. The lower Al content and perhaps the higher Ti content in 1483 compared to X4 resulted in lower TBC lifetimes for 1483. Photo-stimulated luminescence piezospectroscopy (PLPS) and 3D microscopy were used to measure residual stress in the alumina scale and surface roughness, respectively, on specimens with and without a YSZ top coating.

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“…In addition, with the growth of an oxide layer (called thermally grown oxide, TGO) between the ceramic top and metallic bond layers, the two layers delaminate at the interface, which leads to spallation of the ceramic layer [5,6]. Thus, inspection techniques that can assure the reliability of TBCs by evaluating the degree of sintering and detecting delamination at the interface are becoming important [7,8].…”

Section: Introductionmentioning

confidence: 99%

Terahertz dielectric properties of plasma-sprayed thermal-barrier coatings

Watanabe

Katayama

Yamawaki

et al. 2011

Surface and Coatings Technology

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NDE assessment of TBCs: an interim report of a photo-stimulated luminescence ‘round-robin’ test

Cited by 36 publications

References 6 publications

The role of beam dispersion in Raman and photo-stimulated luminescence piezo-spectroscopy of yttria-stabilized zirconia in multi-layered coatings

The role of beam dispersion in Raman and photo-stimulated luminescence piezo-spectroscopy of yttria-stabilized zirconia in multi-layered coatings

The effect of cycle frequency, H2O and CO2 on TBC lifetime with NiCoCrAlYHfSi bond coatings

Terahertz dielectric properties of plasma-sprayed thermal-barrier coatings

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