• Tribology and Lubricants
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• v.22 no.2
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• pp.59-65
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• 2006

In hard disk drives as the head to disk spacing continues to decrease to facilitate recording densities, slider disk interactions have become much more severe due to direct contact of head and disk surfaces in both start/stop and flying cases. The slider disk interaction in CSS (contact-start-stop) mode is an important source of particle generation and tribocharge build-up. The tribocharge build-up in the slider disk interface can cause ESD (electrostatic discharge) damage. In turn, ESD can cause severe melting damage to MR or GMR heads. The spindle speed of typical hard disk drives has increased in recent years from 5400 rpm to 15000 rpm and even higher speeds are anticipated in the near future. And the increasing disk velocity leads to increasing disk acceleration and this might affect the tribocharging phenomena of the slider/disk interface. We investigated the tribocurrent/voltage build-up generated in HDD, operating at increasing disk accelerations. In addition, we examined the effects with relative humidity conditions and rest time. We found that the tribocurrent/voltage was generated during pico-slider/disk interaction and its level was about $3\sim16pA$ and $0.1\sim0.3V$, respectively. Tribocurrent/voltage build-up was reduced with increasing disk acceleration. Higher humidity conditions $(75\sim80%)$ produced lower levels tribovoltage/current. Therefore, a higher tribocharge is expected at a lower disk acceleration and lower relative humidity condition. Rest time affected the charge build-up at the slider-disk interface. The degree of tribocharge build-up increased with increasing rest time.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.96-102
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• 2005

The tribocharge build-up in the slider disk interface can cause ESD (electrostatic discharge) damage. In turn, ESD can cause severe melting damage to MR or GMR heads. We investigated the tribovoltage/current build-up with smooth and textured disks in HDD, operating at increasing disk accelerations. We found that tribe-voltage/current were generated during pico-slider/disk interaction and those levels were about 0.1 ${\~}$ 0.3 V and 10 ${\~}$ 40 pA, respectively. Tribovoltage/current were abruptly increased and dissipated within the acceleration time in the case of textured disk but in the case of smooth disk tribovoltage was continuously increased until the end of uniform velocity region and the tribocurrent did not dissipate within the acceleration time. In the case of textured dist tribovoltage/current was reduced with increasing disk acceleration, but in the case of smooth disk it was increased.