Residual stresses in plasma sprayed partially stabilised zirconia TBCs: influence of the deposition temperature

Scardi, Paolo; Leoni, Matteo; Bertamini, L.

doi:10.1016/0040-6090(95)08163-1

Cited by 51 publications

(14 citation statements)

References 25 publications

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“…Several methods for the determination of residual stresses in plasma-sprayed TBC have been developed, including material removal processes [1], substrate curvature measurements [2][3][4][5], diffraction techniques [6][7][8][9][10][11][12][13][14][15][16], spectroscopic techniques [17][18][19][20][21] and modeling [22][23][24][25][26]. Hole drilling methods allow for the discrete determination of stresses through the coating as material is removed.…”

Section: Introductionmentioning

confidence: 99%

Through-thickness determination of phase composition and residual stresses in thermal barrier coatings using high-energy X-rays

2010

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Section: Introductionmentioning

confidence: 99%

Through-thickness determination of phase composition and residual stresses in thermal barrier coatings using high-energy X-rays

2010

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“…Zirconia-based TBCs require alloying oxides such as Y 2 O 3 , CaO, CeO, MgO, etc., in order to stabilize a single-phase material, usually in the tetragonal form [28]. At room temperature the -9 -equilibrium phases of yttria partially stabilized zirconia are expected to be a low yttria content monoclinic phase and a high yttria content cubic phase.…”

Section: Structural Analysis and Phase Destabilizationmentioning

confidence: 99%

Evaluation of laser-glazed plasma-sprayed thermal barrier coatings under high temperature exposure to molten salts

Batista

Portinha

Ribeiro

et al. 2006

Surface and Coatings Technology

126

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Thermal Barrier Coating (TBC) systems are frequently used in gas turbine engines to provide thermal insulation to the hot-section metallic components and also to protect them from oxidation, hot corrosion and erosion. Surface sealing treatments, namely laser-glazing, have been showing a high potential for extending in-service lifetimes of these systems by improving chemical and thermo-mechanical resistance. In this investigation, both as-sprayed and laserglazed TBCs were exposed to hot corrosion in molten salts. The glazed coatings were obtained by scanning the surface of the plasma-sprayed coatings with either a CO 2 or a Nd:YAG laser.The hot corrosion investigation was accomplished by subjecting the specimens to an isothermal air furnace testing under V 2 O 5 and/or Na 2 SO 4 in a temperature of 1000ºC for 100 hours.Spallation has been observed in coatings in the as-sprayed condition under V 2 O 5 or -2 -V 2 O 5 +Na 2 SO 4 . Na 2 SO 4 itself had no or minimal effect on the degradation of the laser-glazed or as-sprayed condition coatings, respectively. The degradation in V 2 O 5 was accomplished by destabilization of YSZ as a consequence of depletion of yttria from the solid solution to form YVO 4 and therefore led to the disruptive transformation of the metastable tetragonal phase to the monoclinic phase. Moreover, the presence of both corrosive salts induced the formation of large high aspect ratio YVO 4 crystals that introduced additional stresses and contributed to the degradation of the coatings. The laser-glazed specimens were not efficient in avoiding the molten salt penetration along the thickness direction due to the presence of cracks on the glazed layer.However due to a reduced specific surface area of the dense glazed layer, the corrosion reaction of the molten salts with the YSZ has been lower than in coatings in the as-sprayed condition.-3 -

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“…This leads to different microstructures, residual stresses, and physical properties of the coating [3]. Moreover, studies have shown that the residual stress field in a coating is influenced by the deposition temperature and coating thickness [4,5].…”

Section: Introductionmentioning

confidence: 99%

Process Parameter Settings and Their Effect on Residual Stresses in WC/W2C Reinforced Iron-Based Arc Sprayed Coatings

2017

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Abstract:Residual stresses have been a major source of concern, as they are an inevitable consequence of manufacturing and fabrication processes. The magnitude of these stresses is often as high as, or at least, comparable to the yield strength of the material. In terms of arc sprayed coatings, the utilization of bore hole drilling methods presents some practical disadvantages as mechanical parameters (Poisson's ratio, Young's modulus) need to be identified in order to determine the residual stress distribution. Curvature techniques using Almen strips are cost-and time-effective methods that can be used for analytical quality assurance. Within the scope of this work, a quantitative study of the amount of residual stresses induced in a twin wire arc spraying (TWAS) process for a given combination of process parameters was conducted using the incremental bore hole drilling method, as well as the curvature method including Almen strips. Therefore, the effect of the primary gas pressure, substrate preheating temperature, and handling parameters, such as the spray angle and gun velocity, which influence the coating deposition as well as the heat input into the substrate, are examined. The experiments were carried out by using an iron-based cored wire with cast tungsten carbides as filling. The results of both methods are in an acceptable accordance with each other. Different stress fields were observed depending on the parameter settings.

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Residual stresses in plasma sprayed partially stabilised zirconia TBCs: influence of the deposition temperature

Cited by 51 publications

References 25 publications

Through-thickness determination of phase composition and residual stresses in thermal barrier coatings using high-energy X-rays

Through-thickness determination of phase composition and residual stresses in thermal barrier coatings using high-energy X-rays

Evaluation of laser-glazed plasma-sprayed thermal barrier coatings under high temperature exposure to molten salts

Process Parameter Settings and Their Effect on Residual Stresses in WC/W2C Reinforced Iron-Based Arc Sprayed Coatings

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