An effect of dewetting of lubricated surfaces on friction and wear properties

To meet the demand of increased storage density for magnetic data storage, stronger and thinner lubricant films for head disk interface in hard disk drives is desired. It is reported that perfluoropolyether lubricant with polar end groups is dewetted and brings about the flying instability of a magnetic head. In this report the effects of dewetting phenomenon on friction and wear properties are studied. Observations of lubricant film by optical microscopy and friction tests were carried out. The observation showed the lubricated surface became dewetted with time and lubricant droplets were formed. The dewetted area increased with time as shown in the figure and, at the same time, the number of droplets decreased. These results suggest the growth of droplets. From the results of friction tests, it was found that the friction coefficient increased and the lifetime reduced with the growth of droplets. The reason for this will be discussed in this research. (c) 2005 American Institute of Physics.