Dual layer X-ray photoelectron spectroscopy model to simultaneously determine a PFPE/A20H lubricant mixture and carbon layer thicknesses on hard disk magnetic media

To provide good tribological functioning in hard disk drives, an ultrathin layer of lubricant is added to the hard disk surface. To accurately measure the ratio of a mixture of a pure PFPE lubricant and A20H, means to separate their contributions to the XPS spectrum must be devised. The linearity of the correlations demonstrates the method´s capability to quantify a mixture of PFPE and A20H over useable thickness ranges, and to accurately measure carbon thickness independent of lubricant thickness or ratio.