Towards Fracture Mechanics of Thermally Sprayed Metallic Coatings using Indentation Technique for Edge Chipping on a Micron Scale

This paper assesses the fracture toughness of thermally sprayed NiCr, NiCrAlY, Mo, and NiCrBSi layers using an indentation method called edge chipping based on fracture mechanics. The procedure is done in a scanning electron microscope, enabling precise positioning and in-situ observation of crack growth. The paper reviews the basic principles of edge chipping, describes the experimental setup, and presents and analyzes the results. Preliminary test results show a clear correlation between edge toughness and wear under particle erosion. The influence of anisotropic properties parallel and perpendicular to the substrate surface is observed as well. Paper includes a German-language abstract.