Structural-Phase State, Elastic Stress, and Functional Properties of Nanocomposite Coatings Based on Amorphous Carbon

• Published in: Physical mesomechanics Vol. 22; no. 6; pp. 488 - 495
• Main Authors: Korotaev, A. D., Litovchenko, I. Yu, Ovchinnikov, S. V.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-11-2019; Springer Nature B.V
• Subjects: Annealing; Carbon; Chromium; Classical Mechanics; Coatings; Coefficient of friction; Elastic properties; Electron microscopy; Materials Science; Microhardness; Microscopy; Nanocomposites; Physics; Physics and Astronomy; Residual stress; Solid State Physics; Substrates; Titanium alloys; Titanium base alloys; Titanium carbide; magnetron sputtering; amorphous carbon; nanocrystalline particles; microhardness; scratch testing; nanocomposites
• ISSN: 1029-9599; 1990-5424
• DOI: 10.1134/S1029959919060055

The paper analyzes the microstructure and phase state of magnetron-sputtered nanocomposite Ti-C-Ni-Cr coatings based on Ni- and Cr-doped amorphous carbon by transmission electron microscopy, scanning electron microscopy, and X-ray diffraction. The analysis shows that the coating structure comprises an amorphous carbon matrix and nanosized TiC and Ni particles with relatively low lattice bending-torsion (no greater than 75° µm
−1
) and with much lower local internal stress compared to its value in superhard coatings. The microhardness of such coatings on VT1-0 titanium alloy is
H
= 14 GPa, and their friction coefficient is µ < 0.2. The coating structure and properties are stable to annealing up to
T
= 700°C. After annealing at
T
= 900°C, the coating surface reveals TiO, Ti
2
O, and other oxide phases. The results of scratch testing show that the character and the scale of fracture in the coatings depend on the substrate hardness: on soft substrates, the coatings experiences intense cracking and delamination, and on hard alloy substrates, they undergo multifragmented fracture. The coatings on hard alloy substrates survive up to a load of 80 N.