On Adhesion of DCMS-TiAlN Coatings on HiPIMS-bombarded AISI 52100 Steel Substrates

AISI 52100 bearing steel is widely used in high-load, cyclic loading applications where wear and surface fatigue are critical concerns. This study examines the impact of high power impulse magnetron sputtering (HiPIMS-Cr) pretreatment on coating-substrate adhesion before depositing TiAlN (Ti/TiN interlayers) multilayer films via direct current magnetron sputtering (DCMS), and compares the results with those of conventional Ar pretreatment used in commercial PVD recipes. Coatings were characterized using SEM, EDS, XRD, Rockwell indentation, and scratch testing. XRD analysis revealed that HiPIMS-Cr pretreatment modified the preferred crystallographic orientation from a dominant (111) to competitive growth along (111), (200), and (220) reflections. Ar-pretreated films showed finer grains ( 43 nm) and higher hardness (27.1 GPa), while Cr-pretreated coatings had rougher, cauliflower-like morphology ( 73 nm) and slightly lower hardness (24.3 GPa). Despite this, Cr-treated films demonstrated a 17