Tribological characteristics of silane coupling agent-modified graphene oxide/magnesium hydroxide composites under high temperature and high load working conditions
The lubrication performance of grease is prone to deteriorate under high temperature and high load conditions,leading to severe friction and wear.Two-dimensional nanomaterials are widely used as lubricant additives due to their excellent friction-reducing and anti-wear properties,which can significantly improve the tribological performance of lubricating grease.However,their enhancement effect on lubricants is often reduced due to agglomeration.Graphene oxide/magnesium hydroxide[GO-Mg(OH)2,GM]composite material was prepared by the oxidation-reduction method.Silicon coupling agent was used as a modifier to modify the GM particles by high-energy ball milling,resulting in modified graphene oxide/magnesium hydroxide[KH-GO-Mg(OH)2,KGM].The performance of GM and KGM lubrication under high temperature and high load conditions was investigated using a SRV-4 friction and wear tester,and various characterization methods were used to analyze the two materials and the test wear scars.Research analysis showed that KGM had smaller size and thickness than GM.Both GM and KGM,as lubricant additives,could improve the tribological capability of the base grease with the optimal mass fraction being 0.5%.lubrication effect and friction-reducing and anti-wear performance of KGM were more prominent.Under high temperature(150℃)and high load(3.5GPa)conditions,the friction coefficient and wear width were reduced by 36.5%and 33.7%,respectively.KGM formed a lubricating protective film containing iron,magnesium,silicon and oxygen elements through adsorption on the friction surface,which exhibited friction-reducing,anti-wear effects and repair functions.This provided a simple and economical reference for the development of efficient lubricating greases under harsh conditions,holding significant potential and research value in sustainable lubrication.
graphene oxidemagnesium hydroxidecompositeslubricant additivesfriction and wear
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