Influence of dry micro abrasive blasting on the physical and mechanical characteristics of hybrid PVD-AlTiN coated tools

Abstract

The current study investigates the effect of the micro abrasive blasting (MAB) on the physical and mechanical characteristics of the cutting tools before and after coating deposition. Cutting tools were subjected to micro blasting by alumina (Al2O3) grains at varying pressure so as to improve the efficacy of the coating process. AlTiN coating of thickness 1.45 μm was deposited onto the tool surface by arc enhanced high power impulse magnetron sputtering (HiPIMS) hybrid deposition technique. The coatings were characterized using nano indentation, atomic force microscopy and micro scratch test. The results of nano indentations on the coated surface revealed the influence of the micro abrasive blasting technique and pressure on the superficial hardness. Surface morphology results showed better-adhered surface in case of cutting tools subjected to micro abrasive blasting before the deposition due to an increase in density of the nucleation sites for growth of aluminum which can be judged with the help of higher aluminum content in the energy dispersive x-ray analysis. The film adhesion of the coating onto the tool substrate is observed to be improved significantly with an increase in blasting pressure in the case of the samples subjected to micro abrasive blasting before coating. Additionally, X-ray diffraction analysis was performed to investigate crystallographic phases. The attained results provide insight concerning the optimum selection of micro abrasive blasting technique along with the pressure, for enhancing the cutting performance of coated tools during the machining of nickel-based superalloy Nimonic C 263.