Protecting the head/disk interface from the chemical environment with disk drive filtration

An assessment of the chemical environment, within which a disk driveʹs head/disk interface must operate, is presented. This provides the framework for discussing the benefit of an internal, integrated chemical filter (ICF) to the long-term integrity of the head/disk interface. The ICF in the present embodiment has a diffusion limiting channel at the driveʹs breather inlet to minimize the rate of volatile contamination ingress, a mass of chemically treated, activated charcoal to permanently absorb acid gases and volatile organic compounds, and a particle filter to stop the ingress of external particles and charcoal fragments. The activated charcoal has the additional property of reversibly absorbing water vapor, which is used to moderate changes in the humidity within the drive. The design and performance of the ICF are discussed.