Generation and Characterization of A Protective Layer on Steel Tribosurfaces in Presence of Mg_6Si_4O_(10)(OH)_8~©

摘要

A Falex tribotester was employed to in situ generate a protective layer on thern45~# steel surfaces under designed tribological conditions. The tribopair was immersed into thernfinely dispersed mixture of the reconditioner package in a fully formulated multipurposernengine oil of mineral base acting as carrier oil. The key component of the reconditionerrnpackage was superfine powders of magnesium silicate hydroxide (Mg_6Si_4O_(10)(OH)_8). Afterrn400 hours of test running, nearly naught weight losses were measured for the 45~# steelrntribopair, and a protective layer of about 2-3 μm in thickness was observed on therntribosurfaces. Morphology of the layer was observed with SEM, and its mechanical propertiesrnand chemical states were characterized respectively with micro-ano-sclerometers and XPS.rnThe micro- and nano-hardness of the layer were respectively Hv780 and Hv1290 in average,rnapproximately 2-3 times as high as that of the substrate. Chemical identification of the layerrndemonstrated that it was mainly composed of Fe_3O_4, Fe_2O_3 and Fe_3C.