Friction and wear properties of a sulphurized layer formed by low-temperature ion sulphurization on a surface nanocrystallized layer

The solid lubrication film containing sulphide was prepared on the surface nanocrystallized surfacing layer by low-temperature ion sulphurizing technology. The microstructure of the sulphurized layer was analysed. The tribological behaviour of the sulphurized layer based on the nanocrystalline layer was investigated in a dry friction condition. The sulphurized layer on the nanocrystalline layer has high sulphide content, with the FeS phase accounting for a large proportion of this layer. The sulphurized layer based on the nanocrystalline layer is thicker and denser and has a significantly lower friction coefficient than the untreated sample, with 25% reduction in wear volume. Analysis demonstrated that the high active nanocrystalline layer is also beneficial for the formation of a sulphurized layer. In addition, the high-hardness nanocrystalline layer provides an excellent support for the lubricating layer and is beneficial for enhancing the antifriction property.