Influence of Cu Content on the Microstructure and Mechanical Properties of Cr-Cu-N Coatings

Abstract

The Cr-Cu-N coatings with various Cu contents (0–25.18 (±0.17) at.%) were deposited on Si wafer and stainless steel (SUS 304) substrates in reactive Ar+N2 gas mixture by a hybrid coating system combining pulsed DC and RF magnetron sputtering techniques. The influence of Cu content on the coating composition, microstructure, and mechanical properties was investigated. The microstructure of the coatings was significantly altered by the introduction of Cu. The deposited coatings exhibit solid solution structure with different compositions in all of the samples. Addition of Cu is intensively favored for preferred orientation growth along (200) direction by restricting in (111) direction. With increasing Cu content, the surface and cross-sectional morphology of coatings were changed from triangle cone-shaped, columnar feature to broccoli-like and compact glassy microstructure, respectively. The mechanical properties including the residual stress, nanohardness, and toughness of the coatings were explored on the basis of Cu content. The highest hardness was obtained at the Cu content of 1.49 (±0.10) at.%.

Effect of Cu doping on the microstructure and mechanical properties of AlTiVN-Cu nanocomposite coatings

“…Cu, Ag, Ni) have been incorporated into hard coatings to form the nanocomposite structure, which simultaneously exhibited both high hardness and toughness [21]. Among which, it is well know that soft Cu phase exhibit excellent ductility, which could improve coating hardness and toughness [22,23], or even lower the friction coefficient [24,25]. It was reported by Jirout et al [26] that the addition of Cu into ZrO2 coatings altered the microstructure and macrostress, which significantly influenced mechanical properties, such as toughness or brittleness.…”

Comparison of mechanical and tribological properties of CrBN coatings modified by Ni or Cu incorporation

“…Therefore, the development of hard and tough coatings has become the objective of researchers [9][10][11]. Many studies have focused on the crack resistance modification of transition metal nitride coatings by tough metal incorporations, such as Ni [12,13], Cu [14], Ag [15,16], Au [17], Al [18], Nb [19], Ti/Al [20], and Cu/Cr [21]. As a result, the wear resistance of transition metal nitride coatings was enhanced accordingly [13][14][15].…”

“…However, the toughening degree among different tough metals in Refs. [12][13][14][15][16][17][18][19] is incomparable since these tough metals were not compared simultaneously in one article and the hardness decrement was not considered. Namely, it is difficult to distinguish which tough metal exhibits a superior synthetic strengthening effect.…”