ADHESION AND X-RAY ELASTIC-CONSTANT EVALUATION OF CRN COATING

The four-point bending test was used to study the adhesion of CrN coat ings on tool steel, and to determine the X-ray elastic constants (XECs ) for (311) and (200) crystallographic reflections of such (220)-textu red coating. The coating was found to have a nano-microstructure with anisotropic elastic properties. The compressive residual stress in the coating was measured to be high. Plastic deformation in the substrate tool steel with the four-point bending test did not cause flaking of the coating, but can cause tensile transverse cracking when the compre ssive residual stress is relaxed. A comparison was made between the ma croscopic Young' modulus values obtained from the XECs of the (hkl) pl anes examined at orientation factors (3 Gamma) of zero, 0.471 and 0.6. These macroscopic values were found to be close to the XEC value of t he (311) reflection.