Porosity is an important factor in plasma-sprayed coatings, especially ceramic coatings. Excessive porosity can adversely affect the performance of the coated component in various ways. An ultrasonic nondestructive 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 technique, 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 generate 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.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Materials Chemistry