Study On Lubrication Of Ferromagnetic Material With Magnetic Film Array

Magnetic Fluid is a new-style functional material, which is a steady colloid system formed byspreading magnetic particle into the base fluid, and it’s also an excellent lubrication material. Ithas the quality of both fluid and magnetic material. When there is a magnetic field, it can belocated in particular area or direction, and it can also be moved.Surface texture, which is the array of micro-dimples or micro-grooves manufactured on thesurface, and it has already been proved to be an effective method of improving tribologicalperformance. Combining the excellent lubrication performance of magnetic fluid under magneticfield and the excellent tribological performance of surface texture, our group put forward thedesign of magnetic film array.This paper studies on the tribological performance of ferromagnetic material with magneticfilm array. Firstly, geometric parameter of the magnetic film array has been optimized. Thentribological tests have been done on different base material, and the influence of lubricationperformance of magnetic film array caused by the difference of base material has been analyzedwith the help of finite element analysis of static magnetic field. After that, we fulfill the dimpleswith the magnetic film array, and tribological tests have been done on the same specimen beforeand after magnetizing the film array. With this group of tests, the significance of magnetic film inthe lubrication of magnetic fluid has been fully proved. Meanwhile, the influence of lubricationperformance caused by the difference of thickness of the film has also been studied. Finally, theinfluence of lubrication performance caused by the difference of upper specimen has been studied.The main research results are as follows:1. The photolithography, micro-electrochemical machining and electrodepositing method arethe proper way to manufacture the magnetic film array. The magnetic film array has accurategeometric figure and is of high quality. It has been proved that the magnetic film array can reducethe friction coefficient with the lubrication of magnetic fluid under some circumstance. And thebest effect of coefficient-reduction can achieved with the optimization of parameter.2. With the help of analysis of magnetic field in different base material, it has been provedthat the effect of friction-reduction on the surface of45steel is better than that of316steel. Itimplies that the base material influences the lubrication performance of magnetic fluid with theeffect of magnetic film array.3. Comparing the tests on the same specimen before and after magnetizing the film array, itcan be seen that the friction coefficient on the specimen after magnetizing the film is lower thanthat before magnetizing the film, which demonstrates the effect of friction-reduction of magnetic film under the lubrication of magnetic fluid. Meanwhile, the result of tests on the specimen ofdifferent thickness of film shows that the effect of friction-reduction after magnetizing the film ismore obvious on the specimen with thicker magnetic film. It proves that the thickness of magneticfilm can influence the magnetic field intensity, and also influence the lubrication performance ofmagnetic fluid.4. When PTFE is used as the upper sample, the friction coefficient first increases and thendecrease with the increase of the slide speed. This phenomenon becomes more obvious when themagnetic film is thicker. Besides, when under light load, the decrease of coefficient is not obvious,while it is more obvious when under heavy load.