Page 18 - 《摩擦学学报》2021年第6期

第 6 期 陈国庆, 等: 一种油溶性季铵盐离子液体作为PAO基础油添加剂的摩擦学研究 803

and deficiencies in the base oil in lubricating oils to achieve the effect of giving them special properties. For the
improvement of lubrication under these two conditions, the most effective means is to use lubricating additives, which
can form an effective protective film on the surface of the friction pair to prevent friction and wear caused by the direct
contact of the friction pair. For this reason, oil-soluble anti-friction and anti-wear additives are usually added to
lubricating oil to improve its anti-wear and anti-wear performance, so as to meet the lubrication requirements of
machinery under different working conditions. Among different additives, anti-friction and anti-wear agents are of great
significance to the anti-friction, anti-wear and load-bearing properties of lubricants.
In this paper, a new type of oil-soluble quaternary ammonium phosphate ionic liquid (N 88816 P 4 ) was synthesized, and
the thermal stability of each test sample was analyzed on a thermal gravimetric analyzer. The SRV-V fretting friction
and wear tester and surface non-contact optical 3D profiler was used to investigate its tribological performance as anti-
wear additive in base oil polyalphaolefin (PAO 10) and compounded with commercial additive zine
dialkyldithiophosphate (ZDDP). Results showed that N 88816 P 4 had excellent oil solubility and good compatibility with
ZDDP, no obvious stratification and precipitation were observed. The addition of N 88816 P 4 increased the initial thermal
decomposition temperature of the PAO 10 composition, and with the increase of the amount of N 88816 P 4 added, the
thermal decomposition temperature of PAO 10 increased to a certain extent. Under the conditions of room temperature
and high temperature (100 ℃), PAO 10 had an obvious biting phenomenon. The addition of N 88816 P 4 with different mass
fractions significantly improved the occurrence of this phenomenon. And with the increase of N 88816 P 4 , the friction
coefficient and wear volume of PAO 10 gradually decreased. The best tribological performance was obtained at the
additive amount of 2%, i.e. the friction coefficient of 0.1 and the wear volume reduction of 80%. N 88816 P 4 significantly
improved the anti-friction and anti-wear performance of PAO 10. Compared with its compounding with ZDDP, N 88816 P 4
as the additive of PAO 10 showed better anti-friction and anti-wear performance. The tribological performance was best
at the additive amount of 1% because the friction coefficient dropped to about 0.1. The extreme pressure performance
test showed that the addition of N 88816 P 4 reduced the amount of ZDDP without deteriorating the excellent load-bearing
anti-friction performance. The copper corrosion test results showed that N 88816 P 4 was almost non-corrosive, and the
combination of N 88816 P 4 and ZDDP significantly inhibited the corrosion of ZDDP. The surface morphology of the worn
surface was analyzed by a scanning electron microscopy, energy spectrometer and X-ray photoelectron spectrometer
were used to analyze the chemical state on the wear scars. It proved that N 88816 P 4 had complex tribochemical reactions
with the metal substrate. The significant effects for ILs on the friction-reduction and anti-wear performances were
attributed to the formation of tribofilm containing elements N and P on the worn surfaces.
Key words: oil-soluble ionic liquids; ZDDP; additives; tribological properties; lubrication mechanism

[20]
[19]
为满足现代工业飞速发展的润滑需要，设计合成 成氟化氢腐蚀金属基底 . 同时，制备成本高 不易
[1]
新型润滑材料受到越来越多研究工作者的关注 . 润 于工业化大量生产 [21-22] 也是限制因素之一. 近些年来，
滑油作为最为常见的润滑材料，其优异的润滑特性一 油溶性离子液体发展迅速，多种不同种类的低成本油
方面源自润滑油本身的结构特性，另一方面源于润滑 溶性离子液体相继被报道，极大地扩展了离子液体的
[2]
油所包含的各种功能添加剂 . 在不同的添加剂中，减 应用空间，作为润滑油添加剂获得更多的关注 [9,18,20] .
摩抗磨剂对于润滑油的减摩抗磨和承载性能具有非 在润滑领域，ZDDP作为多功能润滑油添加剂使
常重要的意义 [3-5] . 基于此，大量的科研工作者关注合 用最为广泛. 然而，由于ZDDP容易导致汽车尾气的三
成高性能减摩抗磨添加剂 [6-10] . 元催化体系中毒失效，且具有明显的腐蚀性能，致使
自2001年离子液体作为一种新型高效润滑剂被 这类添加剂的使用逐渐受到限制 [23-24] . 随着科技进步
首次报道至今，摩擦学领域的科研工作者相继开展了 和节能环保的政策，对添加剂的环保性能提出了更严
大量的研究工作，相关研究工作在学术领域和应用过 格的要求. 目前，针对ZDDP的使用，普遍采取的解决
程中都取得了许多进展 [11-15] . 尽管如此，传统离子液体 方法是发展新型环境友好型减摩抗磨添加剂来部分
作为基础油润滑添加剂的相关研究依然进展缓慢，主 或者全面替代ZDDP的使用. 基于此作者设计合成了
要原因在于相关研究主要集中于咪唑型离子液体 [16-17] ， 一种新型的季铵盐油溶性离子液体，其分子结构中不
[18]
此类离子液体的油溶性能不佳 ，且分子结构中往往 含卤素和硫元素，且磷含量低，具有环境友好性能. 系
含有六氟磷酸盐和四氟硼酸盐等阴离子，易于水解生 统考察了该离子液体作为PAO 10添加剂的摩擦学性