Effect of pressure driven energy transfer on the microstructure and tribological properties of CrN coatings: A multi-scale modeling and experimental study

A comprehensive multi-scale simulation and experimental study was conducted to elucidate the influence of sputtering pressure on the growth mechanism and performance of CrN coatings deposited by magnetron sputtering. Experimental characterizations revealed that higher sputtering pressures lead to reduced grain density, increased surface roughness, a preferred orientation shift from (200) to (111), and degraded mechanical and tribological properties. The multi-scale simulation framework was used to simulate energy transfer from plasma to atomic deposition and to quantify the energy per arriving atom (EPA) by integrating plasma discharge, sputtering and transport of target atoms, and atomic deposition. Simulations demonstrated that under high pressure the reduced EPA induced by the increased collision effect suppresses adatom mobility, resulting in the island-like growth mode and coarse microstructures. Under low pressure, higher energy transfer facilitates densification and (200)-oriented growth through layer-by-layer growth mode. It was further revealed that ion bombardment plays a critical role in coating densification under low pressure, while the degradation in coating quality was primarily attributed to the decreased energy contribution from energetic neutrals under high pressure. This study provides atomistic insight into the pressure-driven microstructure evolution and offers predictive guidance for optimizing process parameters in plasma-assisted deposition technologies.