Three ecofriendly protic ionic liquids (PILs), 2-hydroxyethylammonium 2-ethylhexanoate, 2-hydroxymethylammonium 2-ethylhexanoate, and 2-hydroxydimethylammonium 2-ethylhexanoate, with different extents of hydrogen bonding and ionicities, were synthesized and examined as neat lubricants and lubricant additives to a mineral oil (MO) under steel/steel and steel/aluminum contacts. The stability of each PIL–MO blend was observed and correlated to their individual structural features; their physicochemical and tribological properties were investigated and compared to a commercial mineral oil-based lubricant. The addition of any PIL to the mineral oil improved lubricity in steel/steel contact. In aluminum/steel contact, the PILs were studied as neat lubricants and additives showing different effects. The PIL with lower extent of hydrogen bonding but higher ionicity presented poor friction and led to higher wear as neat lubricant. However, as additive, this PIL prevented the intense tribo-corrosion reactions and generated a stable lubrication film that reduced friction; and was capable to form a protective layer on aluminum surface to avoid severe wear.

合成了三种生态质子离子液体（PIL），2-乙基己酸2-羟乙基铵，2-乙基己酸2-羟甲基铵和2-乙基己酸2-羟基二甲基铵，它们具有不同程度的氢键和离子性，并作为纯净的润滑剂和润滑剂添加剂进行了研究。钢/钢和钢/铝接触下的矿物油（MO）。观察到每种PIL-MO共混物的稳定性，并将其与各自的结构特征相关联。对它们的理化和摩擦学性能进行了研究，并与市售矿物油基润滑剂进行了比较。向矿物油中添加任何PIL均可改善钢/钢接触中的润滑性。在铝/钢接触中，研究了PIL作为纯净的润滑剂和添加剂，显示出不同的作用。氢键程度较低但离子性较高的PIL摩擦较差，作为纯净润滑剂会导致较高的磨损。但是，作为添加剂，这种PIL可以防止剧烈的摩擦腐蚀反应并产生稳定的润滑膜，从而减少摩擦。并能够在铝表面形成保护层以避免严重磨损。