Abstract:The adsorption behavior of engine oil (Grade SN 5W-40) on the stainless steel surface was studied using Quartz Crystal Microbalance with Dissipation Monitoring (QCMD),and was compared with that of base oil.It is found that the adsorption equilibrium can be quickly established on the stainless steel surface by base oil,and the adlayer is viscoelastic film and is desorbed completely after rinsing using nheptane.The adsorption between engine oil and stainless steel surface is enhanced by the additives in the engine oil,and the mass of adlayer is increased along with the adsorption time.The formed adlayer by the engine oil is viscoelastic film and is partly desorbed after rinsing using nheptane,and then the stable viscoelastic adlayer is formed.The effect of concentration,temperature and injection rate of the engine oil on the adsorption process was investigated.The results show that the mass of saturated adsorption and the stable adsorption mass after rinsing are proportional to the concentration of engine oil.The increase of temperature is unfavorable to the adsorption,but it is beneficial to the desorption of engine oil on the rinsing process,and the desorption rate becomes higher as increasing temperature.The effect of the injection rate of engine oil on adsorption process is not obvious.