Abstract :
Summary form only given, as follows. Sliding experiments between well defined hemispherical pins made of different materials and magnetic thin-film disks were performed in vacuum in order to shed light ain material effects in tribochemistry. A1203, A1203-TiC, amorphous carbon, CaTiO3, MnZn ferrite, and amorphous Si02 were chosen for their potential use as head substrate materials, Wear products from unlubricated diska and disks lubricated with fluorocarbon polymers were monitored in-situ with mass spectrometer. For unlubricated interfaces, decreasing evolution of C, CO, and CO2 during initial eliding wae accompanied by decreasing friction (see Fig. 1). This indicate8 that the friction coefficient of the surface adsorbate is much larger than that of the clean carbon overcoat. When eliding in vacuum, the friction reduce8 while the adsorbate layers are removed. This initial reduction of the friction can not occur in ambient because of high adsorption rate in atmosphere pressure. For lubricated interfacee, fluorocarbon fragments with wide range of masses were generatetd with decreasing rate while friction was low and relatively constant (aee Fig. 2). When magnitude of gaseoue signals increased, frictional variations rose dramatically, hydrogen evolution followed with some delay and wear track was formed. Metal fluorides were detected with a number of eliding materiale. Large differences exist in the rate of generation of gaseoue products with different materiale and they correspond to failure tiwee. Degradation mechanieme are dominated by removal of surface groupe from solid surface and by scission, losees and alteration of fluorocarbon polymers.
