Study On Prepartion And Tribological Properties Of Rare Earth Compounds As Lubrication Additives

As a result of the effect of special 4f electronic structures, coefficient of friction and wear rate of rare earth compounds are significantly different from other compounds. What’s more, rare earth compounds provide layer structure of hexagonal crystal system, these special properties make these elements and their compounds has a good performance of extreme pressure and anti-wear performance as lubricant additives. Rare earth resources is of much abundance in China, but the use of rare earths have large gaps when compared with the developed countries, therefore the research of rare earths as extreme pressure anti-wear agents of lubricating oil is of great practical significance.In this paper, LaF3 nano-particles modified by OAE18A, OAEDEA and DTCDEA were parpared in ethanol-aqueous system by using in-situ surface modification, and its tribological properties were also studied. The product has high purity, particle size in 20-50nm and there was no obvious agglomeration. Preparation conditions:temperature 65℃, response time 1h, volume ratio of ethanol and water is 2:1, mole ratio of modifiers and LaF3 of 2:1, under these conditions, nano-article’s spersion stability, high temperature and low-temperature stability, tribological properties are the best. Stability of nanometer particles decorate by three modifiers significantly better than the LaF3 did not surface modified. Contains surface modified of nano particles of oil sample of friction performance is superior obviously than containing modified agent of oil sample and based oil. DTCEDA surface modified of LaF3 nano-particles’ friction performance were the best. When the concentration of the LaF3 nanoparticles modified by DTCDEA in oil was 0.4%, the minimum wear-scar diameter of product was 0.39mm,29.1% lower than base oil’s; and when the adding amount of the LaF3 nanoparticles modified by DTCDEA was 0.6%, the maximum PB value of product was 1176N,, for based oil of twice times.This article also examined preparation and tribological performance of organic compounds of lanthanum. In the course of preparation of carboxylic lanthanum, when the molar ratio of n(LaCl3):n(carboxylic acids):n(KOH) was 2:6:3, the resulting carboxylic lanthanum of tribological properties of oil-soluble are the best. Three different types of tribological properties of oil-soluble organic compounds of lanthanum had improved markedly compared with the base oil. In these oil-soluble additives, the LADTC had the best extreme pressure performance, when additive content is 3%; maximum PB value of 1078N for best oil anti-wear properties of lanthanum, additive content is 1%, the WSD grinding spot diameter of only 0.36mm.