Publications

Abstract : Silicon (Si) and silver (Ag) doped amorphous carbon (a-C) thin film were deposited on chrome nitrided 316 LVM stainless steel using filtered cathodic vacuum arc (FCVA) deposition technique to obtain Si:a-C and Ag:a-C thin film. The morphology of the films was evaluated using atomic force microscopy, X-ray diffraction, Raman spectroscopy, nanoindentation and nanoscratch tests. The surface quality of Ag:a-C film appeared inferior owing to the formation of Ag agglomerates on the surface. Raman studies indicated higher shifting and narrowing of G-band in Ag:a-C film resulting in increased sp2 hybridization. Also, the ID/IG ratio of Si:a-C film (1.3) was lesser than Ag:a-C (2.3) film indicative of higher sp3 content in the former. This has propounded to improved mechanical attributes such as hardness (24.5 ± 3.8 GPa), elastic modulus (241 ± 14 GPa), H/E (0.103 ± 0.11), H3/E2 (0.282 ± 0.021 GPa) and fracture toughness (2.93 MPa.m1/2) in Si:a-C film. Further, Ag:a-C film suffered severe radial cracks during indentation at higher load owing to debonding. On the other hand, Si:a-C film exhibited the formation of circumferential cracks during indentation attributed to higher compressive stress in the film. What is more, Si:a-C showcased better film adhesion in Rockwell-C adhesion test with lesser delamination at the impression edge. This is further corroborated by microscratch test depicting higher Lc2 value and adhesive energy.