Papers by Keyword: SiO₂ Particles

Abstract: Ti-Si composite ceramic coating containing SiO₂ particles was prepared on 45 steel substrate by in-situ laser pyrolysis with laser power of 600W and laser wavelength of 980nm. The density and wear resistance of the composite ceramic coating were improved. By means of scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), reciprocating friction and wear tester, the element composition, existing forms, surface morphology and friction and wear properties of Ti-Si composite ceramic coatings with different mass fraction of SiO₂ particles were analyzed. The results show that the addition of SiO₂ particles can improve the surface density and inorganic degree of the composite ceramic coating. When the mass fraction of SiO₂ is 1% and the load is 1N, the friction coefficient of the composite ceramic coating is 61% lower than that of 45 steel. When the mass fraction of SiO₂ is 5% and the load is 3N, the friction coefficient of the composite ceramic coating is 51% lower than that of 45 steel. The composite ceramic coatings show good antifriction performance and wear resistance.

Abstract: In the production process of synthetic silica glass, SiCl₄ as precursor is imported in oxyhydrogen flame, SiO₂ particles generate and distribute with different states along the flame. The flame temperature and the distance above the burner are important factors to affect the particle diameters and morphologies. The 2D distribution of flame temperature was measured using sodium line-reversal method. The diameters and morphologies of SiO₂ particles were analyzed by transmission electron microscopy (TEM) at 50mm, 100mm, 200mm, and 300mm above the burner. The results show that the flame temperature ranges from 2130°C to 2320°C, and the average diameter of SiO₂ spherical particles increases from 50nm to 105nm as the distance increasing from 50mm to 200mm. The optimum deposition distance was discussed.

Abstract: In order to improve the surface properties of SiO₂ particles, SiO₂ particles were modified by vinyl triethoxysilane, SiO₂ particles and vinyl triethoxysilane modified SiO₂ particles were characterized by FTIR, SEM and XRD techniques. The results showed that vinyl triethoxysilane has been successfully grafted onto SiO₂ particles and basically there are no changes in the size of SiO₂ particles before and after the modification by vinyl triethoxysilane. XRD results show that the synthesized SiO₂ particles have certain crystallinity.

Abstract: The defoaming agent of silicone oil emulsion containing hydrophobic SiO₂ particles was prepared. The effect of different diameters of SiO₂ particles and amount of SiO₂ particles in the emulsion on the defoaming performance was studied, and the mechanism of defoaming was analyzed. The experimental results showed that when the amount of hydrophobic SiO₂ particles in the emulsion was 1%, the emulsion had good defoaming performance; The emulsion containing nanometer sized SiO₂ particles showed better defoaming performance than that of the emulsion containing micrometer sized SiO₂ particles.