Evaluation of Arc Evaporated Coatings on Rounded Surfaces and Sharp Edges

Johan Bohlmark; Helen Blomqvist; Ludvig Landälv; Shahrad Amerioun; Mats Ahlgren

doi:10.4028/www.scientific.net/MSF.681.145

Paper Titles

Influence of Surface Roughness on Evaluation of Stress Gradients in Coatings
p.121

Thermal Residual Stress Relaxation in Sputtered ZnO Film on (100) Si Substrate Studied In Situ by Synchrotron X-Ray Diffraction
p.127

Residual Stresses and Strength of Hard Chromium Coatings
p.133

Thickness Effect on Microstructure and Residual Stress of Annealed Copper Thin Films
p.139

Evaluation of Arc Evaporated Coatings on Rounded Surfaces and Sharp Edges
p.145

Experimental Verification of the Hole Drilling Plasticity Effect Correction
p.151

Residual Stress Analysis Using the Hole-Drilling Method and Geometry-Specific Calibration Functions
p.159

Residual Stress Measurement in Coated Plates Using Layer Growing/ Removing Methods: 100^Th Anniversary of the Publication of Stoney’s Paper “the Tension of Metallic Films Deposited by Electrolysis”
p.165

Determination of Residual Stresses in Thermal and Cold Sprayed Coatings by the Hole-Drilling Method
p.171

HomeMaterials Science ForumMaterials Science Forum Vol. 681Evaluation of Arc Evaporated Coatings on Rounded...

Evaluation of Arc Evaporated Coatings on Rounded Surfaces and Sharp Edges

Abstract:

This paper presents measurements and cutting tests related to coating features on sharp cutting edges and rounded objects. One typical feature of plasma based deposition processes is the formation of a sheath region around the object to be coated. The formation of the sheath has some implications on the coating of three dimensional objects, since rounded surfaces and edges are subjected to different ion flux density as compared to a flat surface. Solid carbide drills of different diameters were coated with a TiAlCrSiN coating by cathodic arc evaporation. It is noted the deposition rate increases with decreasing drill diameter, and the fraction of elements with high expected mean ionization charge state is higher for a small as compared to a large diameter drill. The observations are explained by Coulomb attraction of ions from the plasma in combination with the sheath to tool radius ratio in combination with resputtering and scattering in the gas/plasma phase. Solid carbide end mills were coated with TiAlN at three different substrate biases; -10, - 40, and - 80 V. It is observed that the coating stresses increase drastically with increasing bias, and the corners of the tools have different stress levels than the flatter areas. In addition, the fraction of Ti in the coating around the corners is increased significantly when the bias increases. The end mills were tested in a machining test, and the best performer was the variant deposited at - 40 V.