The preparation of a series of dispersible nano-SiO2 by surface-modification in situ was described in this paper. It is found that some silane coupling agents can be combined with nano-SiO2 by ...covalent bonds, which change the nanoparticle's surface properties and make nano-SiO2 disperse well and steadily in many organic mediums. The structure of nanoparticles was characterized by transmission electron microscopy (TEM), infrared spectrum (IR), X-ray photoelectron spectra (XPS) and thermogravimetric analysis (TG). The dispersivity of these nanoparticles in organic solvents was measured by light transmittance. Considering such superior dispersion in oily solvents and very small size, we primarily investigated their tribological behaviors as additive in lubricant on wear testers. The results show that they can evidently increase anti-wear ability and reduce the friction coefficient of lubricant.
In this paper, we report a novel preparation method for indium nanoparticles from bulk indium that involves surface oxidation and dispersion of indium droplets. Indium nanoparticles of well-defined ...size are obtained by dispersing melt indium in an appropriate solvent. Powder X-ray diffraction and transmission electron microscopy show the formation of indium nanoparticles possessing the same crystal structure as bulk indium and an average particle diameter of 30 nm. The samples display a strong surface plasmon absorption band at 240 nm, which indicates that the sample is metal indium and the particle size is less than 50 nm. Thermal analysis reveals that the samples contain at least 55 wt % organic solvent. Tribological results show that indium nanoparticles have good antiwear properties.
A tetrafluorobenzoic acid-modified TiO2 nanoparticles with average diameter of 40 nm were chemically synthesized. The nanoparticles were amorphous and had good thermal stability. The nanoparticles ...were characterized by transmission electron microscope, Fourier transformation infrared ray, X-ray Diffraction, and their thermal stability was investigated by means of TGA and differential thermal analysis. The tribological properties of the FA-TiO2 nanoparticles as additive to liquid paraffin were evaluated with a four-ball tester. The morphologies on the worn surfaces of the lubricated GCr15 steel were studied using scanning electron microscope. The results show that the FA-TiO2 nanoparticles exhibit good performance in wear and friction reduction. The antiwear and load capability of liquid paraffin increased and the wear scar diameter strikingly deceased after adding nanometer TiO2.
A new method to prepare silver nanoparticles was posed. Metal nanoparticles can be produced through reduction of relevant metallic salts in liquid ammonia. The method is convenient as compared with ...the similar method. The morphology and structure of synthesized silver nanoparticles were characterized on transmission electron microscopy (TEM), X-ray diffraction (XRD), infrared spectrum (FT-IR) and thermogravimetric analysis (TGA). The result shows that the morphology of Ag nanoparticles is spherical and the mean size is about 20 nm.
A simple and rapid process has been developed for the preparation of indium nanoparticles from bulk indium via ultrasound irradiation. Transmission electron microscopy (TEM) shows the as-prepared ...indium nanoparticles are appear to be close to a spherical shape. X-ray diffraction (XRD) pattern indicates that the samples are the tetragonal phase of indium with the same crystal structure as that of the bulk indium. It is confirmed by X-ray photoelectron spectrum (XPS) analysis that there is an indium oxide layer at the surface of the indium nanoparticles. The tribological property of indium nanoparticles as additives in oil is evaluated on a four-ball tester and shown that indium nanoparticles exhibit good performance in wears.
In this paper, we reported a facile and rapid process to prepare tin nanoparticles from bulk tin via ultrasound dispersion. The morphology and structure of synthesized tin nanoparticles were ...characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS) and thermogravimetric analysis (TGA). The results show that the morphology of tin nanoparticles is spherical and the structure of tin nanoparticles has the same crystal structure as the bulk tin. In addition, the tribological property of tin nanoparticles as additives in oil is evaluated on a four-ball tester and the results show that tin nanoparticles exhibit good performance in wear.
The preparation of a series of dispersible nano-SiO
2 by surface-modification in situ was described in this paper. It is found that some silane coupling agents can be combined with nano-SiO
2 by ...covalent bonds, which change the nanoparticle's surface properties and make nano-SiO
2 disperse well and steadily in many organic mediums. The structure of nanoparticles was characterized by transmission electron microscopy (TEM), infrared spectrum (IR), X-ray photoelectron spectra (XPS) and thermogravimetric analysis (TG). The dispersivity of these nanoparticles in organic solvents was measured by light transmittance. Considering such superior dispersion in oily solvents and very small size, we primarily investigated their tribological behaviors as additive in lubricant on wear testers. The results show that they can evidently increase anti-wear ability and reduce the friction coefficient of lubricant.
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