EVALUATION OF INTERNAL COHESION OF MULTIPHASE PLASMA-SPRAYED COATINGS BY CAVITATION TEST: FEASIBILITY STUDY

Authors

  • Radek Mušálek Czech Academy of Sciences, Institute of Plasma Physics, Department of Materials Engineering, Za Slovankou 1782/3, 182 00 Prague 8, Czech Republic
  • Emanuele Nardozza University of Modena and Reggio Emilia, Faculty of Materials Engineering, via Pietro Vivarelli 10, Modena, Italy
  • Tomáš Tesař Czech Academy of Sciences, Institute of Plasma Physics, Department of Materials Engineering, Za Slovankou 1782/3, 182 00 Prague 8, Czech Republic Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Trojanova 13, 120 00 Prague, Czechia
  • Jan Medřický Czech Academy of Sciences, Institute of Plasma Physics, Department of Materials Engineering, Za Slovankou 1782/3, 182 00 Prague 8, Czech Republic Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Trojanova 13, 120 00 Prague, Czechia

DOI:

https://doi.org/10.14311/APP.2020.27.0073

Keywords:

Cavitation damage, cohesion, failure analysis, plasma spray coatings

Abstract

Mechanical characterization of plasma-sprayed coatings at microscopic level represents a major challenge due to the presence of numerous inherent microstructural features such as cracks, pores, or splat boundaries, which complicate coatings characterization by conventional testing methods. Need for reliable testing of structural integrity of newly developed multiphase plasma-sprayed coatings introduced even more complexity to the testing. In this study, applicability of indirect vibratory cavitation test (adapted from ASTM G32 standard) for such testing was evaluated. Three plasmasprayed coatings having distinctive microstructures were tested: i) conventional alumina coating deposited from coarse powder, ii) hybrid coating deposited by co-spraying of coarse alumina powder and fine yttria-stabilized zirconia (YSZ) suspension, and iii) compact alumina coating deposited from fine ethanol-based suspension. Differences in the coatings internal cohesion were reflected in different failure mechanisms observed within the cavitation crater by scanning electron microscopy and mean erosion rates being i) 280 μm/hour, ii) 97 μm/hour and iii) 14 μm/hour, respectively.

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Published

2020-06-11

Issue

Vol. 27 (2020): Proceedings of the 14th International Conference on Local Mechanical Properties - LMP 2019

Section

Articles

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