Tribological Properties Of Biotite Micro-nanoparticles

The silicate mineral powder used as anti-wear and anti-friction materials is a hot topic in current researches,in which the tribological properties of various silicate mineral powders in different lubricating media are evaluated and a number of experimental data are obtained.However,the studies on the performance and functional mechanism of anti-wear and anti-friction of this novel lubricating additive are still less than perfect.As a result,carrying out a research on silicate mineral additive has an important practical significance,wherein the results can provide experimental and theoretical basis for its industrial application as anti-wear and anti-friction materials.This dissertation presents silicate mineral biotite as the subject,and the biotite powder and biotite/Lanthanum chloride compounds micro-nanoparticles are prepared by mechanical ball-milling method.The friction experiments are carried out systematically in different lubricating medium to examine tribological properties under different conditions,and a variety of advanced methods are adopted to characterize the micro-structure,the element type,the element distribution,and the component of the friction pair surface.The results reveal the anti-wear and anti-friction mechanism of biotite.The anti-wear and anti-friction performance of biotite powders,biotite/Lanthanum compounds as additives for different oil is investigated by steel-steel sliding friction pair of SFT-2M Pin-on-disc Wear Tester at different conditions,and it is proved that biotite has good tribological properties.On this basis,the micro-structure of friction surface is characterized by scanning electron microscopy?SEM?,and the results show that,the addition of biotite results in the formation of a non-uniform tribofilms on the friction pair surface,and the biotite particles exist in the scratch of the friction surface.The element type,the element distribution and the component are detected by energy dispersive X-ray spectroscopy?EDS?and X-ray photoelectron spectroscopy?XPS?.The results show that,the friction surface contains compound component of Al and Mg and other elements from biotite powders.The biotite powders as lubricant additives,produces cleavage and crushing,embedding,depositing and diffusing into the surface of the deep through mechanical force,and forms a melt under flash temperature in some point of contact.Variable net ion from Mg²⁺,Fe²⁺ions of biotite powders undermines Si-O-Si bridging oxygen,forms large amount of unsaturated bonds,active groups and electron position hole with good adsorption and ion exchange properties on the powder surface,which adsorbs lubricant nanoscale metal debris,exchanges metal cation generated from the wear surface,produces a variety of compound with anti-wear and anti-friction.The tribological performance of biotite powders as additive for 500SN base oil is investigated by steel-copper sliding bearing of M-2000A friction and wear machine.Sliding bearing results show that,biotite/base oil completes lubrication and plays a good anti-wear and anti-friction role.Based on above results,the geometry and density location of the self-repairing tribofilm under negative wear affecting on the static characteristics of sliding bearings is simulated.The simulation results show the self-repairing tribofilm,which locates in loading area of the sliding bearings under the negative wear phenomenon conditions,can improve the static characteristics of the bearing.The research results of this dissertation have an important reference value for the further study on the self-repairing characteristic of the sliding friction pair lubricated by biotite micro-nanoparticles.