Experimentelle Untersuchung der Wechselwirkung von Flüssigkeiten und Gasen mit Oberflächen von Magnetspeicherplatten

In this thesis the adsorption behaviour of surfaces of hard disks for magnetic storage devices was simulated with the use of a Quartz Crystal Microbalance (QCM). Investigations of the influence of sputter parameters, aging and the effect of lubrication with perfluorinated polyethers (“lubricants”) showed that oxidation and the diffusion of metal ions of the magnetic storage layers onto the surface of the protecting carbon overcoat (COC) are the key players for the different amounts of nonpolar contaminations adsorbed on the surfaces of such hard disks. Experiments with sulphur dioxide led to a patent for the recycling of hard disks substrates made of glass and to further investigations of corrosive liquids like sodium hypochlorite.

The data out of spectra of lubricants on hard disk surfaces generated by Time of Flight-Secondary Ion mass Spectrometry (TOF-SIMS) were analyzed with statistical approaches. The “Principal Component Analysis” (PCA) defines clusters of samples with the same surface properties and identifies the relevant peaks responsible for the differences between the clusters. The “Partial Least Squares” method (PLS) additionally gives quantitative data about the thickness of lubricant films. This enables the researcher to measure inhomogeneities in the lubricant distribution on a hard disk in the range below 1 nm in a safe and reproducible way.