The storage capacity of hard disk drives (HDD) for personal computers has increased by more than ten thousands times for the last decade. Meanwhile, the gap between disk and head (flying height) has decreased from submicrometers to a few nanometers. Hence, the lower flying height leads to more sensitive disk to surface contamination to link to fatal failures. There have been many studies reporting that the disk surface contamination was related with the adsorption of VOCs and the corrosion of magnetic layer in the disk. However, the surface contamination derived from SO
2 gas in the surroundings has been discussed insufficiently. In this work, we aimed at elucidating the mechanism of the disk surface contamination and the subsequent particle formation by exposing HDD disks to SO
2 gas intentionally, followed by the evaluation of their operation performance during the endurance test. As a result, we found that a large quantity of sulfate and nickel, which was a main component of the disk substrate layer, was detected on the SO
2-contaminated disk surface, while a small quantity of cobalt, which was a main one of the magnetic layer after a series of endurance tests. From these findings, we inferred the following mechanism of surface contamination of HDD disk in the coexistence of SO
2 and water. Nickel is supplied from the substrate layer to the top one through holes and cracks in the films of disk owing to the corrosion triggered by adsorbed water. Eventually, it is deposited on the surface as nickel sulfate to be released in the form of particles by contact with the head.
抄録全体を表示