Mechanical properties of TiN coatings

It is difficult to measure the mechanical properties of physical vapor depo sition coatings owing to their small layer thickness. This report describes a special four-point bending device that makes it possible to determine qu antitative critical tensile or compressive failure stresses and shear stres ses in thin coatings. The bending test was also used to carry out measureme nts of hardness and critical loads (scratch test) under stress, excluding o ther influences such as microstructure changes. The material parameters det ermined form the basis of a finite element model of the indentation process , and this offers new possibilities for mechanical characterization of coat ed materials.