| Water-based lubricating materials have attracted wide attention as metal working fluid and anti-combustion hydraulic fluid due to their excellent properties such as antiflaming property and high cooling characteristic.However,they usually have several shortcomings such as poor lubricity and anti-corrosivity,which limit their further industrial applications.How to effectively solve these problems has become the key to the wide application and promotion of water-based lubrication materials.Ionic liquids,as a kind of high efficient water-based lubricant additives,can improve the lubrication and anticorrosion properties of water-based lubricants.In this paper,we have facilely synthesized several water solube ionic liquids to investigate their lubrication and anticorrosion properties in water lubricants and demonstrated the structure-activity relationship and lubrication mechanism by means of exploring the impact of diferent structures of anion and cation in the ionic liquids on the lubrication and anticorrosion properties of water-glycol fluid.The specific research contents and corresponding conclusions of this paper are achieved as follows.(1)Several diacid ionic liquids were synthesized by acid-base neutralization and characterized by IR and NMR.We studied the anti-corrosion and lubricating properties of diacid ionic liquids as water-based lubrication additives in waterglycol fluid.The results showed that sebonic acid based ionic liquid could effectively inhibit the corrosion rate of metal in water,and 2-(1,3-benzothiazole-2-thiyl)succinic acid based ionic liquid had better lubrication performance.0.5 wt% 2-(1,3-benzothiazole-2-thiyl)succinic acid-choline ionic liquid([CBC])effectively reduced wear volume by about 25% compared with waterglycol solution.This may be attributed to the the synergistic effect from the adsorption film of ionic liquids on the metal surface and the tribofilm resulting from the tribochemical reaction of active elements with the surface.(2)Several diamine ionic liquids were synthesized by proton transfer between Br(?)nsted acid and Br(?)nsted base andinvestigated their anti-corrosion properties in water-based fluid.The results showed that the ricinoleic acid diamine ionic liquid could significantly improve the corrosion resistance of water-based lubricant to the metal material due to the strong adsorption of the polar functional group in the ionic liquid on the metal surface.Besides,we investigated the tribological properties under different conditions such as frequency and load.The tribological tests showed that diamine ionic liquids could reduce the friction coefficient of water glycol by more than 35% and the wear volume by one order of magnitude.Considering corrosion resistance and lubrication performance,the diamine ionic liquids significantly outperformed the diacid ionic liquids.(3)In view of the lubrication and anti-corrosion properties of diacid ionic liquids and diamine ionic liquids in water-based lubricants,a binary hybrid ionic liquid(PILHB)was synthesized as a multi-functional additive in WG solution.The anti-corrosion and lubrication effects of different concentrations of [PILHB] on metal surface were studied and the optimal concentration was 1%.We further investigated the effect of load on lubrication performance.The [PILHB] showed better lubrication and corrosion resistance than the above two kinds of ionic liquids.Based on the worn surface analysis and contact angle test,the mechanism of anti-corrosion and lubrication was discussed,which was attributed to the formation of physical adsorption film and chemical reaction film on the friction pair surface. |
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