Measurement of the Young’s Modulus of Thermal Spray Coatings by Means of Several Methods

Abstract

Abstract Thermally sprayed coatings are usually defined by their hardness, porosity, roughness and wear resistance. Even though the Young’s modulus is an essential property, which describes the mechanical behavior of the coated components during their use, only few efforts were made to determine this property. The most common measurement methods of the Young’s modulus of thermally sprayed coatings are tensile tests, bending tests, and nanoindentations. During the tensile and bending tests a sliding of the splats can occur due to the laminar structure of the thermally sprayed coatings, influencing the measurement value. When using the nanoindentation test, only the elastic behavior of a single splat can be determined because of a minimal measuring volume. 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 values of the Young’s moduli of thermally sprayed coatings, measured by several methods are compared with each other and correlated to the microstructure of the coatings, investigated by means of scanning electron microscopy.