Tribological Behavior of Amorphous Carbon Nitride Overcoats for Magnetic Thin-Film Rigid Disks

TLDR

Amorphous carbon nitride films of 5–30 nm were deposited on 65–95 mm magnetic thin‑film disks by single‑ and dual‑cathode magnetron sputtering in nitrogen‑argon plasmas. The coatings exhibit 22–28 GPa hardness, 0.25 nm rms roughness, and deliver three‑to‑four times better pin‑on‑disk durability and superior start‑stop performance than amorphous carbon, making them a promising next‑generation overcoat.

Abstract

Abstract Amorphous carbon nitride coatings of thickness of 5 and 30 nm were deposited onto 65 and 95 mm magnetic thin-film rigid disks surfaces using single-cathode and dual-cathode magnetron sputtering systems containing nitrogen-argon plasmas. Under optimum deposition conditions, amorphous carbon nitride coatings can be synthesized on ultrasmooth thin-film disks with no significant pinholes at thickness down to 5 nm, with hardness 22–28 GPa (compared to 7–12 GPa for amorphous carbon), and r.m.s. roughness as low as 0.25 nm. These amorphous carbon nitride coatings were shown to have better contact-start-stop performance and three-to-four times better pin-on-disk contact durability compared with amorphous carbon overcoats under identical testing conditions. Amorphous carbon nitride appears to be a promising candidate overcoat material for replacing amorphous carbon in the next-generation magnetic thin-film rigid disk systems.