Study On The Tribological Properties Of Borate Addictive Based On Marine Lubricant Oil

In this paper,lauric acid sodium salt(LASS)and cetyl trimethyl ammonium bromide(CTAB)are selected to be ball-milling process control agents,which are the anion and cation type surface-modifiers.Surface modificated K2B4O7 powder is prepared by plasma-assisted ball milling device.Normal dry milling,plasma-assisted dry milling,normal wet milling,plasma-assisted wet milling are employed in the preparation of surface modificated K2B4O7 addictive,and the milling process is optimized by characterizing the powder.The morphologies of powder prepared by different ball milling processes showed that large quantity powder prepared by normal dry milling and plasma-assisted dry milling is adhered to the wall of the milling tank and severe caking and agglomeration appears.The productive rate is only 10%.Powder prepared by normal wet milling has slight agglomeration,while powder prepared by plasma-assisted wet milling doesn't appear this,and the diameter of the powder is from 300 nm to 400 nm,the productive rate is 65%.XRD analysis showed that grain size of the particle prepared by plasma-assisted wet milling is the smallest,only 11.28 nm.The synergy between plasma and wet milling media has effectively improved the efficiency of grain refinement.The tribological properties of the particle dispersed in the DCA 5040 marine cylinder oil are tested under normal load and extreme pressure conditions.The tribological properties of borate additives are tested under the condition that the load is from 100 N to 200 N and the rotating speed is 100r/min.Surface modificated K2B4O7 powder has good anti-friction effect.With the increase of the load,surface modificated K2B4O7 powder is more easily deposited in friction surface,forming a repair layer.Spectral analysis result showed when the load increases,the content of B in the oil decreases,which indicating that load increase is good for K2B4O7 transferring from the compound oil to the friction surface and plays a well role in anti-friction and anti-wear performance.Extreme pressure property test showed that when the load is from 550 N to 800 N and the rotating speed is 100r/min,surface modificated K2B4O7 additive can improve the extreme pressure property of the lubricating oil.And in the long process of using,the K2B4O7 powder's property is given its full play.Spectral analysis showed that the content of Fe has no significantchange with time goes on,but the B gradually decreases,indicating that the K2B4O7 powder in the compound oil transferred from the lubricant oil to the friction surface,which plays a good anti-wear and anti-friction performance.The ferrographic analysis showed that when the load is increased to 700 N,the friction pair with the base oil lubricating begins to appear abnormal wear,while the friction pair with compound oil lubricating is in a normal wear state.The results of energy dispersive microanalysis(EDS)on the worn surfaces under the conditions of800N-100r/min with compound oil lubricating,indicated that in the process of friction,the K2B4O7 particles are absorbed in the friction surface and spread vater membrane,playing anti-friction effect.Meanwhile friction chemical reaction may occur to the K2B4O7 particles during friction process and B element penetrates into the surface of the friction material,playing a good anti-wear effect under extreme pressure condition.