Tribological and mechanical properties of Ti/V/N-containing graded DLC coatings

This study investigates the structural, mechanical, and tribological properties of two novel functionally graded diamond-like carbon (DLC) coatings-Ti-TiC-TiVC-a:C and Ti-TiC-TiVC-TiVCN-a:C-deposited on AISI M2 tool steel via closed-field unbalanced magnetron sputtering. The coatings, with thicknesses of 1.5 mu m and 1.7 mu m respectively, were engineered to overcome the intrinsic challenges of DLC coatings, such as high residual stress and poor adhesion. A significant enhancement in microhardness was achieved, with values reaching 1300 HK0.(0)(1) (0.1 N) for the Ti-TiC-TiVC-a:C coating and 1425 HK0.(0)(1) (0.1 N) for the Ti-TiC-TiVC-TiVCN-a:C coating, substantially exceeding the substrate hardness of 800-850 HK0.(0)(1). Scratch testing revealed excellent adhesion, with critical load (Lc) values of 24 N and 21 N, indicating only a minor trade-off for the nitrogen-enriched variant. Both coatings exhibited an exceptionally low and stable friction coefficient of 0.09. Crucially, the incorporation of a nitrogen-rich TiVCN interlayer led to a remarkable 33% improvement in wear resistance, reducing the wear rate from 1.0 x 10-5 mm3/N<middle dot>m to 6.7 x 10-6 mm3/N<middle dot>m. These findings demonstrate that vanadium-based graded DLC systems, particularly those utilizing carbonitride phases, offer a superior balance of high hardness, exceptional wear resistance, and excellent lubricity, making them prime candidates for advanced tribological applications.

Journal

SURFACE ENGINEERING

Year

2026

Volume

42

Issue

2

Pages

217-228

ISSN

0267-0844

eISSN

1743-2944

DOI

10.1177/02670844261421392

WoS UID

WOS:001686436200001