Optimisation of Mechanical Properties of Gradient Zr-C Coatings

• Published in: Materials Vol. 14; no. 2; p. 296
• Main Authors: Szparaga, Łukasz, Bartosik, Przemysław, Gilewicz, Adam, Mydłowska, Katarzyna, Ratajski, Jerzy
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 08.01.2021; MDPI
• Subjects: Adhesion; Adhesives; anti-wear coatings; Carbon; Cracks; FEM modeling; Fracture toughness; functionally graded materials; Functionally gradient materials; gradient coatings; Interfaces; Load; Magnetic properties; Magnetron sputtering; Mechanical properties; optimisation; Optimization; Physical vapor deposition; Protective coatings; Residual stress; Scratch tests; Shear stress; Simulation; Spatial distribution; Substrates; Transition layers; Tribology; Wear resistance; Zirconium; functionally graded materials; optimisation; gradient coatings; anti-wear coatings; FEM modeling
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma14020296

One of the key components of the designing procedure of a structure of hard anti-wear coatings deposited via Physical Vapour Deposition (PVD) is the analysis of the stress and strain distributions in the substrate/coating systems, initiated during the deposition process and by external mechanical loads. Knowledge of residual stress development is crucial due to their significant influence on the mechanical and tribological properties of such layer systems. The main goal of the work is to find the optimal functionally graded material (FGM) coating's structure, composed of three functional layers: (1) adhesive layer, providing high adhesion of the coating to the substrate, (2) gradient load support and crack deflection layer, improving hardness and enhancing fracture toughness, (3) wear-resistant top layer, reducing wear. In the optimisation procedure of the coating's structure, seven decision criteria basing on the state of residual stresses and strains in the substrate/coating system were proposed. Using finite element simulations and postulated criteria, the thickness and composition gradients of the transition layer in FGM coating were determined. In order to verify the proposed optimisation procedure, Zr-C coatings with different spatial distribution of carbon concentration were produced by the Reactive Magnetron Sputtering PVD (RMS PVD) method and their anti-wear properties were assessed by scratch test and ball-on-disc tribological test.