The Study On Design And Tribological Performance Of Salt Spray Resistant Grease

With the implementation of“Marine Power”Strategy and“Belt and Road Initiative”strategy,the mechanical equipment in a long running suffers from the complex and diverse conditions,including environmental conditions(high/low temperature,salt spray,water spray,etc)and working conditions(high/low speed,high load,etc).The resulting friction,wear and corrosion are extremely serious,influencing the service life and reliability.Lubricating grease is regared as a class of material with excellent sealing/lubrication function,which is suitable for solving the wear and corrosion problems.Regulating the fundamental constituents of lubricating grease is to achieve the development of physicochemical and lubricating properties,thereby matching the damands of lubrication and sealing for modern or future moving parts in mechanical equipments.The text starts with fundamental constituents of lubricating grease(base oil and thickener)to regulate the physicochemical performance,corrosion resistance and tribological performance.The details are as follows:(1)Regulating the base oil and thickener with different types and proportionsIn order to investigate the effect of base oil type,thickener type and concentration on performance of grease,the mineral oil(500SN)and synthetic oil(PAO40)was thickened by the lithium complex soap and polyurea thickener with the concentrations of 20 wt%,15 wt%and 10 wt%.The results illustrated that:as-synthesized grease has excellent corrosion resistance performance;the lithium complex grease containing 80 wt%base oil possesses the best physicochemical performance;the polyurea grease containing 90 wt%base oil has the best tribological performance;the tribological performance of polyurea grease is superior than lithium complex grease;the tribo-chemical reaction film and grease film act as the friction-reducing and anti-wear effect.(2)Regulating the performance of lithium complex grease by binary acidThe performance of lithium complex grease was regulated by binary acid with different structure(including adipic acid,sebacic acid,phthalic acid,dodecanedioic acid and the combination of sebacic acid and phthalic acid in the molar ratio of 1:1,1:2,2:1).The conclusions are as follows:the formulation of sebacic acid possesses the best physicochemical performance;the formulation of adipic acid possesses the best tribological performance;the synergy effect of tribo-chemical reaction film and oil film contribute to the enhancement of friction-reducing and anti-wear performance.(3)Regulating the performance of polyurea grease by organic aminesThe performance of polyurea grease was regulated by organic amines with different structure(including octadecylamine,cyclohexylamine,p-toluidine and their combinations in the molar ratios of 1:1,1:2,2:1).The conclusions are as follows:the formulation of cyclohexylamine/p-toluidine in the ratio of 2:1 possesses the best physicochemical performance;as-prepared grease shows excellent corrosion resistance;the formulation of cyclohexylamine/p-toluidine in the ratio of 1:2 possesses the best tribological performance;the synergy effect of tribo-chemical reaction film and grease film contribute to the enhancement of friction-reducing and anti-wear performance.(4)The combination of calcium sulfonate and lithium complex soapThe performance of complex thickener grease was regulated by the combination of lithium complex soap and calcium sulfonate in the molar ratios of 1:1,1:2,2:1.The conclusions are as follows:the C+P 2:1 possesses the best physicochemical performance;as-prepared grease shows excellent corrosion resistance;the formulation of lithium complex soap and calcium sulfonate in the ratio of 1:2 possesses the best tribological performance;the synergy effect of tribo-chemical reaction film(Fe O(OH),Fe₂O₃,Ca O,Ca CO₃,Li OH)and grease film contributes to the enhancement of friction-reducing and anti-wear performance.