Nitrogen-doped carbon (CNX) overcoats, ranging from 1 to 6nm in thickness, were deposited on magnetic recording disks by a DC-sputtering process. A critical load, based on the first occurrence of coating damage, was used as a semi-quantitative measure of the mechanical strength of these overcoats. It was found that the critical load decreased in a nearly linear manner with the CNX thickness from 6nm down to ∼2nm regime. However, the 1nm thick CNX coating deviated from this trend with a significant decrease in critical load. High-resolution SEM was employed to find the critical loads as well as to reveal the details of the coating wear morphology and the CNX failure mechanism.