ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The microhardness, H, and Young's modulus, E, of a polycrystalline diamond film and several amorphous diamondlike carbon (DLC) films were determined from force-displacement curves obtained using an ultralow-load microhardness instrument (UMIS-2000). Measurements were made at a constant loading rate of 3 mN/s, to a maximum applied force of 67 and 100 mN with contact force of 0.06 and 1.07 mN, respectively. The diamond film had a surface morphology typical of microwave plasma chemical vapor deposition films (crystallite size 0.5–3 μm), and the force-displacement curves showed nearly complete elastic behavior. The average values of hardness (80–100 GPa) and modulus (500–533 GPa) are comparable to those of natural (001) diamond reference standards (H=56–102 GPa, E=1050 GPa). The DLC films were prepared by low-energy ion-assisted unbalanced magnetron sputtering. By varying the bombarding ion energy, five films were prepared having different sp3/sp2 bonding ratios (3–6), optical gaps (1.2–1.6 eV), and hydrogen concentrations (4–20 at %). The force-displacement measurements are characterized by substantial elastic recovery, and individual films show a very narrow range of hardness and modulus values. It is found that high hardness and improved modulus in DLC films correlate with increasing ion energy, sp3/sp2 bonding ratio, and energy gap. Individual films have mean values of hardness and elastic modulus in the range 12–30 GPa and 62–213 GPa, respectively.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.351530
Permalink
