Synthesis And Tribological Properties Of N-containing Heterocyclic Without Sulphur And Phosphorus Lubricating Additives

There has been an increasing interest in the development of lubricating additives along with the strengthening of environmental protection consciousness of the world, as well as the harsh working conditions of machinery and the increasingly stringent of the environmental regulations. More and more people require environmental friendly additives such as sulfur-free, phosphate-free or low-sulfur, low-phosphorus and highlighting antiwear, friction reduction performance. It is necessary to research and develop environmental friendly and more excellent performance lubricating additives in this field.Two types of nitrogen-containing heterocyclic compounds without sulfur and phosphorus were designed and synthesized with anthranilic acid, aliphatic alcohol and amine of linear chain, which are 5-alkoxy-[1, 2, 4] triazolo [4, 3-a] quinazoline and 5-alkylamino-[1, 2, 4] triazolo [4, 3-a] quinazoline. Those compounds synthesized were added to liquid paraffin(base oil). Firstly there main chemical structures were characterized by using IR and 1HNMR and there thermal stability was analyzed by the thermal gravimetric analysis. Results indicated that the structures of six kinds of compounds were the same with the molecular of the designed additives. Their lowest thermal decomposition temperature was about 130℃ and all were able to meet the requirements of the general working conditions.Then the tribological properties of two types of additives were tested by means of a four-ball machine. Compared with zinc dialkyl dithiophosphates(T202) about the tribological properties and the tribological properties of two kinds of additive were compared. The results showed that: Those compounds synthesized were added to rapeseed oil by different mass fractions which could improve extreme pressure of the liquid paraffin, the PB of the additives whose bearing capacity was best was 80% times as much as that of base oil. Six kinds of additives with proper amount could improve the antiwear and friction reduction properties of base oil. And the tribological performance of additives would increase when the alkyl chains of additive molecular became longer. The friction reduction performance of two additives is better than the T202. The antiwear of 5-alkoxy-[1, 2, 4] triazolo [4, 3-a] quinazoline are better than T202, while that of 5-alkylamino-[1, 2, 4] triazolo [4, 3-a] quinazoline are almost worse than T202. The bearing capacity of two kinds additives have little difference. The antiwear of 5-alkoxy-[1, 2, 4] triazolo [4, 3-a] quinazoline are better than 5-alkylamino-[1, 2, 4] triazolo [4, 3-a] quinazoline, while the friction reduction of which are worse than 5-alkylamino-[1, 2, 4] triazolo [4, 3-a] quinazoline.Finally, the scanning electron microscope(SEM) and X-ray photoelectron spectroscopy(XPS) were used to evaluate the worn surfaces of steel balls and the chemical state of the friction surface elements. The results showed that probably the tribological reaction happened between additives synthesized and tribological pairs under boundary lubrication condition, which generated a complex lubricating film, thereby the tribological properties of the base oil liquid paraffin was improved.