Structures and high temperature frictional behaviors of carbonaceous mesophases doped with metallic element nickel (Ni) through mechanical alloying

Abstract

Incorporation of metallic element Ni into a coal tar pitch-derived carbonaceous mesophase (CM) was performed through mechanical alloying in a high energy ball mill apparatus. The structures for the raw and Ni-doped carbonaceous mesophases were characterized by X ray diffraction and Laser-Raman spectroscopic techniques, and the frictional behavior for the carbonaceous mesophases were investigated by using a SRV high temperature friction and wear tester. The results have shown that, the Ni-doped carbonaceous mesophase through mechanical alloying shows a drop in the crystallinity and a decrease in the size of graphite planar micro-crystals, implying a transition to the amorphous structures caused by the mechanical alloying. In addition, the carbonaceous mesophases display a high temperature lubrication effect, and, compared with the carbonaceous mesophases without mechanical alloying, the Ni-doped carbonaceous mesophase from mechanical alloying can provide more evident and longer lasting time high temperature lubrication effect. It can be assumed the there probably exists some correlation between the high temperature lubrication effect for the carbonaceous mesophases and the variation in microcrystalline planar size (La) of the tribo-induced structures from the CM.