The wear resistance of thermal spray coatings mainly depends on coating properties such as the microstructure, hardness, and porosity, as well as on the residual stress in the coating. The residual stress is induced by a variety of influences e.g. temperature gradients, difference of the thermal expansion coefficient of the coating / substrate materials, and the geometry of the components. To investigate the residual stress, the Impulse Excitation Technique was employed to measure the Young’s and shear moduli. The residual stress was determined by using the hole-drilling method and X-ray diffraction. Pin-on-Disc and Pin-on-Tube tests were used to investigate the wear behavior. After the wear tests, the wear volume was measured by means of a 3D-profilometer. The results show that the value of the residual stress can be modified by varying the coating thickness and the substrate geometry. The compressive stress in the HVOF-sprayed WC-Co coatings has a significant positive influence on the wear resistance whereas the tensile stress has a negative effect.

A special pin-on-disc test setup designed for vacuum environments was used to conduct wear tests in a large chamber scanning electron microscope. Arc-sprayed NiCrBSi and HVOF-sprayed WC-12Co coatings were tested using a pin with an Al 2 O 3 ceramic ball as the wear counterpart. During testing, different wear mechanisms were identified and the processes were recorded in short video streams.

This study investigates the wear resistance of WC-FeCSiMn coatings deposited on 3D surfaces by two-wire arc spraying. Wear behavior was evaluated by means of pin-on-disc testing, pin-on-rotating tube testing, and a method in which a robot arm moves a pin over test specimens with arbitrary surface geometries. Residual stresses were determined by incremental hole drilling and were found to have a dependency on substrate geometry. After wear testing, a 3D profilometer determined wear volume and coating surfaces were examined by SEM. The results indicate that wear resistance is strongly influenced by the geometry of the substrate.

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.