A novel approach for determining fracture toughness of hard coatings on the micrometer scale

Abstract

A novel approach is introduced enabling characterization of the mechanical properties of hard coatings on the microscale. The method is based on bending experiments of chemically etched and focused ion beam shaped free-standing coating microcantilevers. The coating itself remains unaffected by the preparation, thus completely preserving its interface with surface features. The determination of fracture toughness, fracture stress and Young’s modulus is demonstrated on as-deposited and annealed sputtered CrN coatings, and reveals a dominant intergranular brittle fracture and annealing-induced grain boundary weakening.