Study on the properties of a epsilon-Fe3N-based magnetic lubricant prepared by DBD plasma

摘要

The epsilon-Fe3N-based magnetic lubricant which is stable and high saturation magnetization has been prepared by a homemade DBD device under the atmospheric pressure. The results show that the NH3 flow rate, the applied peak-to-peak voltage and the mass ratio of surfactant and carrier lubricant have important effects on the phase structure, the magnetic properties, the size of ferroparticles and the stability of the epsilon-Fe3N-based magnetic lubricant. TEM images show the epsilon-Fe3N ferroparticles are dispersed in the carrier lubricant homogeneously, and the cluster phenomenon is not observed. The stable epsilon-Fe3N-based magnetic lubricant with the saturation magnetization of 50.11 mT and the mean ferroparticle size of 11 nm is prepared successfully. The main particles of the atmospheric-pressure Ar/NH3/Fe(CO)(5) DBD plasma are NH, N, N+, Fe, N-2, Ar, H-alpha, and CO; NH is a decomposition product of NH3. Fe and N active radicals are two elementary species in the preparation of the epsilon-Fe3N-based magnetic lubricant in the atmospheric-pressure DBD plasma. There are two discharge modes for DBD plasma, namely, multi-pulse APGD and filamentary discharge. By increasing the applied peak-to-peak voltage from 4600 to 7800 V, the discharge mode is changed from single-pulse APGD with filamentary discharge to two-pulse APGD with filamentary discharge, and the Lissajous figure also converts from a quadrilateral with one step to two steps on the right-hand side.