Oleic acid-capped lanthanum borate(abbreviated as OA/La BO_3·H_2O) nanosheets were prepared by the hydrothermal method. The microstructures of as-prepared OA/La BO_3·H_2O were characterized by means of SEM, ...Oleic acid-capped lanthanum borate(abbreviated as OA/La BO_3·H_2O) nanosheets were prepared by the hydrothermal method. The microstructures of as-prepared OA/La BO_3·H_2O were characterized by means of SEM, TEM, EDS, FTIR and XRD, respectively. Moreover, the friction and wear properties of OA/La BO_3·H_2O as a lubricant additive in rapeseed oil were evaluated on a four-ball tribotester. The tribochemical characteristics of worn surfaces were investigated by SEM and XPS. The results showed that the hydrophobic OA/La BO_3·H_2O nanosheets exhibited their morphology with a diameter in the range of 100 nm to 300 nm and a thickness of about 25 nm, and displayed excellent dispersing stability in rapeseed oil. In the meantime, the rapeseed oil doped with OA/La BO_3·H_2O nanosheets markedly decreased the friction and wear of steel balls, and the optimal friction-reducing and antiwear ability of rapeseed oil was obtained at an OA/La BO_3·H_2O content of 1.0%. The outstanding tribological performance of OA/La BO_3·H_2O in rapeseed oil was attributed to the formation of a composite boundary lubrication film mainly composed of lubricious tribochemical species of B_2O_3, La_2O_3 and Fe_2O_3, and deposits of OA/La BO_3·H_2O nanosheets as well as the adsorbates of rapeseed oil on rubbed surfaces.展开更多
Since the 1990 s, the kerosene fuel(code: JP-8) had been applied in the ground equipment provided with direct injection compression ignition engines in the U.S. Army, resulting in increased occurrence of injection pum...Since the 1990 s, the kerosene fuel(code: JP-8) had been applied in the ground equipment provided with direct injection compression ignition engines in the U.S. Army, resulting in increased occurrence of injection pump failures. Anti-wear additives must be used in the single fuel due to its poor lubricity. In the present work, lubricity improvers were selected on the basis of molecular simulation theoretically and these agents were evaluated to improve the lubricity of jet fuel using the high frequency reciprocating rig(HFRR) apparatus and the ball-on-cylinder lubricity evaluator(BOCLE). It was revealed that dimer acid with higher value of adsorption energy on the Fe(110) plane surface had more efficient lubricity promoting properties than that of naphthenic acid. The experimental results suggested that the dimer acid had a better tribological behavior compared with that of naphthenic acid used as lubricity improver of jet fuel. And addition of anti-wear additives at a dosage of 15 μg/g was able to promote the lubricity of jet fuel to a required level on BOCLE, while a higher concentration over 80 μg/g was needed to improve the lubricity to a demanded value of diesel on HFRR.展开更多
基金the financial support of the National Natural Science Foundation of China(Project 50975282)
文摘Oleic acid-capped lanthanum borate(abbreviated as OA/La BO_3·H_2O) nanosheets were prepared by the hydrothermal method. The microstructures of as-prepared OA/La BO_3·H_2O were characterized by means of SEM, TEM, EDS, FTIR and XRD, respectively. Moreover, the friction and wear properties of OA/La BO_3·H_2O as a lubricant additive in rapeseed oil were evaluated on a four-ball tribotester. The tribochemical characteristics of worn surfaces were investigated by SEM and XPS. The results showed that the hydrophobic OA/La BO_3·H_2O nanosheets exhibited their morphology with a diameter in the range of 100 nm to 300 nm and a thickness of about 25 nm, and displayed excellent dispersing stability in rapeseed oil. In the meantime, the rapeseed oil doped with OA/La BO_3·H_2O nanosheets markedly decreased the friction and wear of steel balls, and the optimal friction-reducing and antiwear ability of rapeseed oil was obtained at an OA/La BO_3·H_2O content of 1.0%. The outstanding tribological performance of OA/La BO_3·H_2O in rapeseed oil was attributed to the formation of a composite boundary lubrication film mainly composed of lubricious tribochemical species of B_2O_3, La_2O_3 and Fe_2O_3, and deposits of OA/La BO_3·H_2O nanosheets as well as the adsorbates of rapeseed oil on rubbed surfaces.
文摘Since the 1990 s, the kerosene fuel(code: JP-8) had been applied in the ground equipment provided with direct injection compression ignition engines in the U.S. Army, resulting in increased occurrence of injection pump failures. Anti-wear additives must be used in the single fuel due to its poor lubricity. In the present work, lubricity improvers were selected on the basis of molecular simulation theoretically and these agents were evaluated to improve the lubricity of jet fuel using the high frequency reciprocating rig(HFRR) apparatus and the ball-on-cylinder lubricity evaluator(BOCLE). It was revealed that dimer acid with higher value of adsorption energy on the Fe(110) plane surface had more efficient lubricity promoting properties than that of naphthenic acid. The experimental results suggested that the dimer acid had a better tribological behavior compared with that of naphthenic acid used as lubricity improver of jet fuel. And addition of anti-wear additives at a dosage of 15 μg/g was able to promote the lubricity of jet fuel to a required level on BOCLE, while a higher concentration over 80 μg/g was needed to improve the lubricity to a demanded value of diesel on HFRR.
