Tribological modification of nano attapulgite powders on wear surface

The attapulgite powders, which mainly contained the elements of Mg, Al, O, Si, were dispersed into the diesel engine lubricant oil CD 15W/40 with the mass fraction of 0.5 % to make a contrast oil sample. The X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to investigate the phase composition and particle morphology of the experimental attapulgite powders. The tribological modification research of wear surface was examined using a block-on-ring friction-wear tester. After that, the contourgraph, focus ion-beam scanning electron microscope (FIBSEM), energy dispersive X-ray detector (EDX) and TEM were used to analyse the wear mass loss, wear surface morphologies, elements and substance phase of the rubbed surface, respectively. Then the tribological modification mechansms of wear surface were also discussed. The results show that, the attapulgite belongs to the one dimension nano material, and it can reduce the value of wear mass loss about 2/3 of rubbing pair dispersed in lubricant oil, and the rubbed surfaces are smooth lubricated with the mineral powders. In the tribological process, a modified film with thickness about 10-20 nm forms due to complex chemical reactions at the interface of attapulgite and rubbing pair. The film composted crystalline and amorphous SiO ₂ and aluminosilicate salt which contains the elements of Al, Fe, Si, O, C has anti-wear property.