Tribological Properties of Gray Cast Iron Lubricated with PAO and Amine Salt of Alkoxyl Phosphate Additive

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.

Keywords

• cast iron
• friction
• wear
• tribochemistry
• pao
• zndtp
• xps