tailieunhanh - Báo cáo y học: "Gold-ionic liquid nanofluids with preferably tribological properties and thermal conductivity"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Gold-ionic liquid nanofluids with preferably tribological properties and thermal conductivity | Wang et al. Nanoscale Research Letters 2011 6 259 http content 6 1 259 o Nanoscale Research Letters a SpringerOpen Journal NANO IDEA Open Access Gold-ionic liquid nanofluids with preferably tribological properties and thermal conductivity Baogang Wang1 3 Xiaobo Wang1 Wenjing Lou1 and Jingcheng Hao1 2 Abstract Gold 1-butyl-3-methylimidazolium hexafluorophosphate Au Bmim PF6 nanofluids containing different stabilizing agents were fabricated by a facile one-step chemical reduction method of which the nanofluids stabilized by cetyltrimethylammonium bromide CTABr exhibited ultrahighly thermodynamic stability. The transmission electron microscopy UV-visible absorption Fourier transform infrared and X-ray photoelectron characterizations were conducted to reveal the stable mechanism. Then the tribological properties of these ionic liquid IL -based gold nanofluids were first investigated in more detail. In comparison with pure Bmim PF6 and the nanofluids possessing poor stability the nanofluids with high stability exhibited much better friction-reduction and anti-wear properties. For instance the friction coefficient and wear volume lubricated by the nanofluid with rather low volumetric concentration X 10-3 stabilized by CTABr under 800 N are and lower than that of pure Bmim PF6 confirming that soft Au nanoparticles Au NPs also can be excellent additives for high performance lubricants especially under high loads. Moreover the thermal conductivity TC of the stable nanofluids with three volumetric fraction X 10-4 X 10-4 and X 10-3 was also measured by a transient hot wire method as a function of temperature 33 to 81 C . The results indicate that the TC of the nanofluid X 10-3 is higher than that of Bmim PF6 at 81 C but no obvious variation at 33 C. The conspicuously temperature-dependent and greatly enhanced TC of Au Bmim PF6 nanofluids stabilized by CTABr could be attributed to micro-convection caused by the .