To enhance the lubricating and extreme pressure(EP) performance of base oils, two types of oil-soluble ionic liquids(ILs) with similar anion albeit dissimilar cations were synthesized. The physical properties of the prepared ILs were measured. The anticorrosion properties of ILs were assessed by conducting corrosion tests on steel discs and copper strips, which revealed the remarkable anticorrosion properties of the ILs in comparison with those of the commercial additive zinc dialkyldithiophosphate(ZDDP). The tribological properties of the two ILs as additives for poly-α-olefin-10(PAO10) with various mass concentrations were investigated. The tribological test results indicate that these ILs as additives are capable of reducing friction and wear of sliding contacts remarkably as well as enhance the EP performance of blank PAO10. Under similar test conditions, these IL additives exhibit higher lubricating and anti-wear(AW) performances than those of ZDDP based additive package in PAO10. Subsequently, X-ray photoelectron spectroscopy(XPS) and energy dispersive spectrometer(EDS) were conducted to study the lubricating mechanism of the two ILs. The results indicate that the formation of tribochemical film plays the most crucial role in enhancing the lubricating and AW behavior of the mixture lubricants.
Guowei HUANGQiangliang YUZhengfeng MAMeirong CAIFeng ZHOUWeimin LIU
Owing to their high surface area,stable structure and easy fabrication,composite nanomaterials with encapsulation structures have attracted considerable research interest as sensing materials to detect volatile organic compounds.Herein,a hydrothermal route is designed to prepare foam shapedα-MoO_(3)@SnS_(2)nanosheets that exhibit excellent sensing performance for triethylamine(TEA).The developed sensor,based onα-MoO_(3)@SnS_(2)nanosheets,displays a high response of 114.9 for 100 ppm TEA at a low working temperature of 175℃with sensitivity higher than many other reported sensors.In addition,the device shows a wide concentration detection range(from 500 ppb to 500 ppm),good stability after exposure to air for 80 days,and excellent selectivity.The superior sensing characteristics of the developed sensor are attributed to the high crystallinity ofα-MoO_(3)/SnS_(2),excessive and accessible active sites provided by the good permeability of porous SnS_(2)shells,and the excellent conductivity of the encapsulation heterojunction structure.Thus,the foam shapedα-MoO_(3)@SnS_(2)nanosheets presented herein have promising practical applications in TEA gas sensing devices.
Metal sulfide nanomaterials have attracted great interest because of their excellent properties and promising applications in sensing,energy harvesting,magnetic and optoelectronic devices,especially their well-aligned crystalline nanostructures are highly desirable for the enhanced performance and novel applications.In this study,the cobalt monosulfide(CoS)nanofibers with uniform shape and good crystallinity were firstly obtained via electrospinning and atmospheric calcination routes under controllable conditions.It was found that the CoS nanofibers exhibited ethanol sensing properties at the optimum working temperature of 200℃,the response was 11.6 toward 100×10^(-6) ethanol gas,and the CoS nanofibersbased sensor exhibits a short response time and recovery time of 5 and 6 s at the optimum temperature,respectively,the result also shows that the sensor has good stability after 50 days,which would be a favorable characteristic as a promising sensor.In addition,the Pauli paramagnetic property of CoS nanofibers was also investigated at room temperature.
