Nanosized copper powders were prepared by a gel-casting method using copper nitrate, acrylamide（AM） and N, N′-methylenebisacrylamide（MBAM） as the main raw materials. The as-prepared copper powders were characteri...Nanosized copper powders were prepared by a gel-casting method using copper nitrate, acrylamide（AM） and N, N′-methylenebisacrylamide（MBAM） as the main raw materials. The as-prepared copper powders were characterized by X-ray diffractometry and scanning electron microscopy, and then added into a 48# industrial white oil. Dispersion and wear properties of the compounded lubricating oil were tested. The results show that the copper powders prepared are of high purity, fine dispersibility with mean particle size of about 60 nm and with a narrow particle size distribution. The nanosized copper powders can be well dispersed in the lubricating oil. The addition of the copper powders obviously improves the anti-wear properties of the lubricating oil owing to their good self-repairing performance. Compared with 48# industrial white lubricating oil, the friction coefficient of GCr15 steel with the compounded oil containing 0.6% copper powders reduces by 0.07 and nearly no wear chippings are found in the scratches of the friction counter parts.展开更多
Friction and wear behavior of AZ91D and its nanocomposites reinforced by different contents of hybrid multi-walled CNTs and nano-SiC particulates under oil lubrication was investigated using a MRS-10P four-ball tribom...Friction and wear behavior of AZ91D and its nanocomposites reinforced by different contents of hybrid multi-walled CNTs and nano-SiC particulates under oil lubrication was investigated using a MRS-10P four-ball tribometer.Friction coefficients and wear rates were measured within a load range of 200-1000 N at a spindle rotary speed of 380 r/min.Worn surface morphologies,phase and element compositions were studied by scanning electron microscope(SEM),X-ray diffraction(XRD)and energy dispersive spectroscopy(EDS),respectively.The mechanism of synergistic effect of CNTs and SiC nanoparticles was discussed.The results indicate that the AZ91D nanocomposites show better wear resistance properties and different wear mechanisms compared with AZ91D.The AZ91D nanocomposites reinforced with 0.5%CNTs and 0.5%nano-SiC have the best tribological capacity.The wear mechanisms for the Mg-based hybrid nanocomposites appear to be a mix-up of micro-ploughing,micro-cutting,slight adhesive wear and delamination.展开更多
In this paper,an ab initio,local density functional(LDF)method was used to explore the relationship between the molecular properties of additives and the lubricating performance of aluminum rolling oil.The structural ...In this paper,an ab initio,local density functional(LDF)method was used to explore the relationship between the molecular properties of additives and the lubricating performance of aluminum rolling oil.The structural properties of butyl stearate,dodecanol,docosanol,and methyl dodecanoate were studied according to the density functional theory.The calculated data showed that the atoms in or around the functional groups might be likely the reacting sites.Because of the different functional groups and structure of ester and alcohol,two types of complex additives,dodecanol and butyl stearate,methyl dodecanoate and butyl stearate,respectively,were chosen for studying their tribological properties and performing aluminum cold rolling experiments.The test results agreed with the calculated results very well.The complex ester,viz.methyl dodecanoate and butyl stearate,had the best lubricating performance with a friction coefficient of 0.084 1 and a permissive-rolling thickness of 0.040 mm as compared with that of dodecanol-butyl stearate-base oil formulation.展开更多
The tribological properties of combinative addition of nano-MoS2 and nano-SiO2 to the base oil have been investigated with a reciprocating ball-on-plate tribotester for magnesium alloy-steel contacts. The results demo...The tribological properties of combinative addition of nano-MoS2 and nano-SiO2 to the base oil have been investigated with a reciprocating ball-on-plate tribotester for magnesium alloy-steel contacts. The results demonstrate that the optimum mass ratio of nano-SiO2 to nano-MoS2 is 0.25：0.75. The optimum combinative addition into the base oil reduces the friction coefficient by 43.8% and the surface roughness （Sa） by 31.7% when compared to that found with the base oil. Meanwhile, the combinative addition of nano-MoS2 and nano-SiO〉 in comparison with single nanoparticles addition, is more pronounced in terms of the lubrication film stability. The excellent tribological properties of the SiO2/MoS2 combinations are attributed to the formation of physical adsorption films and tribochemical products during the rubbing process and the micro-cooperation of various nano- particles with different shapes and lubrication mechanisms.展开更多
基金Project(51674095)supported by the National Natural Science Foundation of China
文摘Nanosized copper powders were prepared by a gel-casting method using copper nitrate, acrylamide（AM） and N, N′-methylenebisacrylamide（MBAM） as the main raw materials. The as-prepared copper powders were characterized by X-ray diffractometry and scanning electron microscopy, and then added into a 48# industrial white oil. Dispersion and wear properties of the compounded lubricating oil were tested. The results show that the copper powders prepared are of high purity, fine dispersibility with mean particle size of about 60 nm and with a narrow particle size distribution. The nanosized copper powders can be well dispersed in the lubricating oil. The addition of the copper powders obviously improves the anti-wear properties of the lubricating oil owing to their good self-repairing performance. Compared with 48# industrial white lubricating oil, the friction coefficient of GCr15 steel with the compounded oil containing 0.6% copper powders reduces by 0.07 and nearly no wear chippings are found in the scratches of the friction counter parts.
基金Projects(11272072,11672055)supported by the National Natural Science Foundation of China
文摘Friction and wear behavior of AZ91D and its nanocomposites reinforced by different contents of hybrid multi-walled CNTs and nano-SiC particulates under oil lubrication was investigated using a MRS-10P four-ball tribometer.Friction coefficients and wear rates were measured within a load range of 200-1000 N at a spindle rotary speed of 380 r/min.Worn surface morphologies,phase and element compositions were studied by scanning electron microscope(SEM),X-ray diffraction(XRD)and energy dispersive spectroscopy(EDS),respectively.The mechanism of synergistic effect of CNTs and SiC nanoparticles was discussed.The results indicate that the AZ91D nanocomposites show better wear resistance properties and different wear mechanisms compared with AZ91D.The AZ91D nanocomposites reinforced with 0.5%CNTs and 0.5%nano-SiC have the best tribological capacity.The wear mechanisms for the Mg-based hybrid nanocomposites appear to be a mix-up of micro-ploughing,micro-cutting,slight adhesive wear and delamination.
基金the financial support of this study provided by the National Natural Science Foundation of China(No.51274037)the Cooperation Program between USTB and SINOPEC(No.112116)
文摘In this paper,an ab initio,local density functional(LDF)method was used to explore the relationship between the molecular properties of additives and the lubricating performance of aluminum rolling oil.The structural properties of butyl stearate,dodecanol,docosanol,and methyl dodecanoate were studied according to the density functional theory.The calculated data showed that the atoms in or around the functional groups might be likely the reacting sites.Because of the different functional groups and structure of ester and alcohol,two types of complex additives,dodecanol and butyl stearate,methyl dodecanoate and butyl stearate,respectively,were chosen for studying their tribological properties and performing aluminum cold rolling experiments.The test results agreed with the calculated results very well.The complex ester,viz.methyl dodecanoate and butyl stearate,had the best lubricating performance with a friction coefficient of 0.084 1 and a permissive-rolling thickness of 0.040 mm as compared with that of dodecanol-butyl stearate-base oil formulation.
基金supported by the National Natural Science Foundation of China(Grant No.51171212)Chongqing Science and Technology Commission(Grant Nos.CSTC2012JJJQ50001,CSTC2013jcyj C60001&cstc2012gg B50003)+2 种基金the National Science and Technology Program of China(Grant No.2013DFA71070)the Fundamental Research Funds for the Central Universities(Grant No.CDJZR13138801)the Fundamental Research Funds for the Yangtze Normal University(Grant No.CJSF2010C025)
文摘The tribological properties of combinative addition of nano-MoS2 and nano-SiO2 to the base oil have been investigated with a reciprocating ball-on-plate tribotester for magnesium alloy-steel contacts. The results demonstrate that the optimum mass ratio of nano-SiO2 to nano-MoS2 is 0.25：0.75. The optimum combinative addition into the base oil reduces the friction coefficient by 43.8% and the surface roughness （Sa） by 31.7% when compared to that found with the base oil. Meanwhile, the combinative addition of nano-MoS2 and nano-SiO〉 in comparison with single nanoparticles addition, is more pronounced in terms of the lubrication film stability. The excellent tribological properties of the SiO2/MoS2 combinations are attributed to the formation of physical adsorption films and tribochemical products during the rubbing process and the micro-cooperation of various nano- particles with different shapes and lubrication mechanisms.
