Analysis of four-point bending test for Nb, Ta, and V-doped CrYN thin films deposited by closed-field unbalanced magnetron sputtering

Yaylali, Banu, Gulten, Gokhan, Yesilyurt, Mustafa, Totik, Yasar, Kulczyk-Malecka, Justyna ORCID: https://orcid.org/0000-0002-4905-3635, Kelly, Peter ORCID: https://orcid.org/0000-0003-1008-4941 and Efeoglu, Ihsan (2025) Analysis of four-point bending test for Nb, Ta, and V-doped CrYN thin films deposited by closed-field unbalanced magnetron sputtering. Surface and Coatings Technology, 518. 132903. ISSN 0257-8972

Preview

Accepted Version Available under License Creative Commons Attribution. Download (10MB) | Preview

Abstract

The increasing expectations and requirements for engineering materials are steadily compelling researchers to evolve and innovate further. Adding transition metals to coating architectures is becoming increasingly attractive as it improves structural and mechanical properties. In this work, CrYN thin films incorporating transition metals Nb, Ta, and V were deposited on a 316L stainless steel substrate using Closed Field Unbalanced Magnetron Sputtering (CFUBMS) with a DC and Pulsed-DC power supply. The microstructural properties of the thin films were analyzed using scanning electron microscopy (SEM), while X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) provided a comprehensive understanding of the coating structure by providing information on crystallographic and surface chemical properties. Mechanical properties were evaluated using nanoindentation testing, which provided accurate measurements of hardness and elasticity, while scratch testing assessed critical load values. In addition, four-point bending tests were performed at room temperature to characterize the CrYN:Nb/Ta/V transition metal nitrides (TMNs), providing a more comprehensive analysis of the mechanical behavior (bending strength and elastic modulus) and adhesion properties of the coating. The mechanisms of coating damage (crack formation and density, spalling, flaking, and separated coating particles) were analyzed as a result of four-point bending tests. The Taguchi approach was employed to investigate how deposition parameters—such as target current, duty cycle, and pulse frequency affect elastic modulus and bending strength. Superior structural (homogeneous and dense film) and mechanical properties (CrYN:Nb/Ta/V high hardness values of 21.4, 18.2, 16.1 GPa, and bending strengths of 707, 711, and 709 MPa, respectively) were obtained. The positive correlation between hardness and bending strength points to an enhancement in the overall durability of the thin film.