Use of nitrogen-implanted chromium overcoat for improving the durability of thin-film magnetic media

Abstract

A feasibility study of the use of nitrogen- implanted chromium as a protective overcoat for thin-film magnetic media was undertaken. Computer hard disks that were pre- sputtered with chromium were implanted with nitrogen using the plasma source ion implantation (PSII) process to produce a chromium nitride containing layer approximately 25 nm thick. Elemental concentration-depth profiles were determined with a scanning Auger microprobe. The presence of chromium nitride in the implanted layer was verified by examination of the broad scan of the Auger spectra. The durability of the PSII-treated hard disks relative to those with a standard carbon overcoat has been characterized with nanohardness, pin- on- disk and thin- film head- on- disk wear tests. A vibrating sample magnetometer was used to evaluate the magnetic properties of the disks. It has been demonstrated that PSII processing has the potential to improve the durability of hard disks without any significant reduction in the magnetic properties.