Physical effects of intra-drive particulate contamination on the head-disk interface in magnetic hard disk drives

The physical damage at the Head-Disk Interface (HDI), caused by common ceramic particles found in the manufacturing environments of the heads and disks in hard magnetic disk drives, is reported. The need for this study arises from industry wide reliability problems due to particulate induced damage at the HDI. The intent of this study is to characterize the head/disk damage caused by 1 μm diamond, 1-2 μm TiC particles. 0.2-1 μm alumina particles, the alumina and TiC grains sintered to make Al-TiC (the slider body), and sputtered alumina. These particles were introduced to the HDI in over thirty disk drives. The drives were then made to perform magnetic recording and retrieval operations for known data sequences, with the resultant reading errors tabulated. After the functional testing, the drives were opened and resulting damage was examined with a number of surface characterization tools. This study confirms that the severity of problems with the read-back signal, caused by particle damage, has an inverse relationship with the magnetic track width. In addition, the harshness of physical damage to the HDI has a positive relationship with particle hardness. Finally, particle shape and size can be contributing factors in damaging the HDI.