Measurement of the Young's Modulus of Thermal Sprayed Coatings by Means of Several Methods

Hardness, porosity, roughness and wear resistance are usually determined to characterize thermally sprayed coatings. Recently, other mechanical properties such as the Young’s Modulus are investigated as well. The Young’s Modulus is an essential property, which describes the mechanical behavior of the coated components during their use. The most common measurement methods of an elastic modulus of thermally sprayed coatings are tensile tests, bending tests, and nano-indentations. During the tensile and bending tests a sliding of the splats can occur due to the lamellar structure of thermally sprayed coatings. Nano-indentations, because of a minimal measuring volume, determine only the elastic behavior of a single splat. However, the Young’s Modulus of thermally sprayed coatings can also be determined by means of a resonant method, called impulse excitation technique (IET). 

In this paper, the Young’s Modulus of thermally sprayed coatings are measured with several methods and the values are compared with each other. In order to correlate the microstructures of the coatings with the measured Young’s Modulus, the cross sections of the coatings are investigated by means of scanning electron microscopy.