The purpose of this paper is to investigate the hydrolytic stability of several S‐hydroxyethyl N,N‐dialkyl dithiocarbamate‐derived borates SNB1, SNB2, and SNB3, to evaluate their tribological performances used as additives in polyalpha olefins (PAO), and to explore the tribochemical action mechanism.
First, the three additives are synthesized and characterized. Second, the hydrolytic stabilities of the three compounds are investigated. As the third step, they are, respectively, added to PAO and a series of samples with different concentrations of the additives in PAO are prepared, respectively. Their tribological properties are evaluated with two types of four‐ball machines, and then the wear scars were observed using a JSM‐5600LV scanning electron microscope. Finally, the elements on the worn surface are analyzed with a X‐ray photoelectron spectroscope (XPS).
The three novel compounds possess relatively good hydrolytic stabilities, excellent anti‐wear (AW) performances, friction reduction properties, and load‐carrying capacity. There is an optimum concentration of each of the three additives for their AW properties. According to the XPS analytical results, a boundary lubrication protective film has formed during friction consisting of FeSO4 film, Fe2O3 film, and the complicated adsorption film composed of N‐containing organic compounds. In the protective films, a large quantity of compounds containing element B is not found.
The antioxidation performances and the anticorrosion properties are not estimated.
Three novel AW/extreme pressure (EP) additives are synthesized, and may be they have the potential industrial application as AW/EP additives in lubricating oil.
The present work provides a research method of N,S‐containing organic borates as lubricating oil additives.
