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5. The tribological behavior of thiophosphates as additives in rapeseed oil

Author

Weimin Liu, Gong Qingye, and He Wanren

Subjects
chemistry.chemical_classification, Rapeseed, Materials science, Base (chemistry), Scanning electron microscope, Mechanical Engineering, Metallurgy, Tricresyl phosphate, Surfaces and Interfaces, Tribology, Steel ball, Surfaces, Coatings and Films, Thiophosphate, chemistry.chemical_compound, chemistry, Chemical engineering, Mechanics of Materials, Lubrication
Abstract

Two kinds of thiophosphate, tri-n-octyl thiophosphate and tri-n-octyl tetrathiophosphate, were synthesized. The tribological behavior of the synthetic compounds and tricresyl phosphate as additives in rapeseed oil for steel-steel frictional pair was investigated with a four-ball machine. The relationship between the additive structure and tribological properties was explored, while the lubrication mechanisms of the additives were investigated as well. Thus the worn surfaces of the steel ball lubricated with the additive-containing rapeseed oil were analyzed by means of X-ray photoelectron spectrometry and scanning electron microscopy, and the elemental compositions and distributions in the worn steel surfaces were observed and determined with an EPMA-810Q electron probe micro-analyzer. It has been found that the synthetic thiophosphates as additives in rapeseed oil at proper concentrations show better tribological properties than tricresyl phosphate. Tribochemical reactions were involved for steel–steel frictional pair lubricated with the rapeseed oil containing thiophosphates, with the formation of a boundary lubricating and protecting film composed of glyceride of rapeseed oil and tribochemical reaction products of the lubricants. This contributes to improve the tribological properties of the rapeseed oil base stock.

Published
2003

6. Insights into the Effect of the Adsorption Preference of Additives on the Anisotropic Growth of ZSM-5 Zeolite.

Author

Shi J, Du Y, He W, Zhao G, Qin Y, Song L, Hu J, Guan Y, Zhu J, Wang C, Teng J, and Xie Z

Abstract

Zeolite morphology plays a crucial role in affecting catalytic performance, while is persistently challenging to tailor through crystal anisotropic growth. It has been recognized that specific additives can be introduced into the synthesis of zeolites to achieve anisotropic growth, however their role and the underlying mechanism are not well understood. Herein, the effect of eight specific additives on the anisotropic growth of the ZSM-5 zeolite is unveiled within the framework of crystallization engineering. Either an inhibition effect or a promotion effect is revealed for each additive according to the crystallization kinetics. The adsorption preference of typical additives on different surfaces was demonstrated by total internal reflection fluorescence microscopy (TIRFM) and transmission X-ray microscopy (TXM) together with 3D reconstruction. The calculated adsorption energy difference between MFI [100]/[101] and [010] surfaces was proposed as a key descriptor to estimate the possible morphology induced by additive. ZSM-5 zeolites varying from sphere-like, plate-like to noodle-like morphology could be synthesized by employing specific additives with increasing adsorption strength difference on distinct surfaces., (© 2022 Wiley-VCH GmbH.)

Published
2022
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