Effect of Hydroxyl Silicate particulates as an Additive on the Friction and Wear Behavior of Mild Steel/Ductile Cast Iron Pair
羟基硅酸盐润滑油添加剂对45#钢/球墨铸铁摩擦副摩擦磨损性能的影响

An MM-200 friction and wear tester was performed to evaluate the friction and wear behavior of 1045 steel/ductile cast iron pair under the lubrication of 650SN oil and the 650SN containing hydroxyl silicate particulates as the additive (The latter oil specimen was coded as KF-1). The worn surface and cross-section of the AISI1045 steel block were observed using a scanning electron microscope, and the elemental composition on the worn surface of the steel block was examined using an energy dispersive X-ray analyzer. It was found that the inorganic mineral particulates as the additive led to increased friction coefficient and wear volume loss of the ductile cast iron ring at a relatively shorter test duration, which was attributed to the abrasion action of the particulates. The friction and wear of the frictional pair under the lubrication of KF-1 was significantly decreased at an extended test duration, which was attributed to the embedding strengthening effect of the inorganic particulates to the worn steel surface. Namely, a friction-modified layer was formed on the worn steel surface under the lubrication of the KF-1, and the relevant worn steel surface had a much larger microhardness than the one under the lubrication of the base stock alone. At the same time, the surface-modified layer in the former case was porous, which helped to entrap the lubricating oil therein and to enhance the boundary lubricating function as well. Subsequently, the friction and wear of the frictional pair was greatly decreased at a large enough test duration.