Abstract
The friction and wear properties of gray cast iron (FC250) specimens sliding against AISI 52100 steel ball were evaluated under the lubrication of PAO (poly-alpha-olefin), PAO+ZnDTP (1.5 mass% ZnDTP) and PAO+PN (amine salt of alkoxyl phosphate, 1.5 mass% PN) oils. The tests were conducted using an Optimol SRV reciprocating friction and wear tester at a normal load of 50 N, and sliding frequencies of 10, 20, 30, 40 and 50 Hz. The morphologies of the worn surfaces of the FC250 specimens were observed using a scanning electron microscope (SEM) with energy dispersion X-ray spectroscopy (EDS). In addition, the elemental compositions and chemical states of several typical elements on the worn surfaces of the FC250 specimens were examined by means of X-ray photoelectron spectroscopy (XPS). The results indicated that the PAO+PN lubricant exhibited higher wear-resistance and lower friction coefficients than pure PAO and the PAO+ZnDTP lubricants, and this was partly attributed to the tribo-chemical reaction between the lubricant and the sliding surfaces.
