Effects of a hierarchical pore structure on the tribological properties of an oil-containing iron-based composite

Oil-containing materials depend on micropore structures to store lubricating oil. However, the micropore structure, an important component of such materials, is difficult to control. Herein, a porous iron-based oil-containing material was successfully prepared via powder metallurgy with TiH2 and polyamide 66 short fiber as dual pore formers. Scanning electron microscopy observations and analyses indicated that the complementary effect of dual pore formers enabled the formation of an interconnected hierarchical pore structure with two pore types, which not only provided abundant oil storage spaces but also facilitated the transfer of oil within the materials. Based on ring-on-block friction and wear tests, the iron-based oil-containing composite presented a low coefficient of friction (about 0.078) under a contact pressure of 1.2 MPa.