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Ultrasonic technique for measuring porosity of plasma-sprayed alumina coatings

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Abstract

Porosity is an important factor in plasma-sprayed coatings, especially ceramic coatings. Excessive poros-ity can adversely affect the performance of the coated component in various ways. An ultrasonic nonde-structive measurement technique has been developed to measure porosity in plasma-sprayed alumina coatings. The technique is generic and can be extended to other ceramic coating systems. To test the tech-nique, freestanding alumina coatings with varying levels of porosity were fabricated via plasma spray. Samples with varying porosity, obtained through innovative fabrication techniques, were used to gener-ate a calibration curve. The ultrasonic velocity in the low-frequency range was found to be dependent on the density of freestanding coatings (measured via Archimedian techniques). This dependence is the basis of the development of a technique to measure the density of coatings.

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Author notes

  1. S. Parthasarathi

    Present address: Western Digital Corporation, 95054, Santa Clara, CA, USA

Authors and Affiliations

  1. Concurrent Technologies Corporation, 15904, Johnstown, PA, USA

    S. Parthasarathi & E. J. Onesto

  2. Pennsylvania State University, 16802, University Park, PA, USA

    B. R. Tittmann

Authors
  1. S. Parthasarathi
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  2. B. R. Tittmann
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  3. E. J. Onesto
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Parthasarathi, S., Tittmann, B.R. & Onesto, E.J. Ultrasonic technique for measuring porosity of plasma-sprayed alumina coatings. J Therm Spray Tech 6, 486–488 (1997). https://doi.org/10.1007/s11666-997-0035-3

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  • DOI: https://doi.org/10.1007/s11666-997-0035-3

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