Preparation And Research On Carbon/Oxides Composite Powders

The paper use inorganic salts (such as AlCl3, Al2(SO4), Al(NO3)3,Na2SiO3, TiCl3, CrCl3, ZrOCl2 et al) as raw materials, by the procession of hydrolyze and deposition of hydroxides on the surface of graphite, composite powders of carbon/oxides obtained after heat treatment. It mainly discerned two kinds of questions.The first is the influence of preparing conditions on the quality of coating. By the analysis of micrograph, coating percent and particle size of composite powders, it finds out that factors such as Ksp, electronic properties, methods of salts added in, temperature, raw materials et al have influence on it. When coating AhC^, ZrC>2, TiC>2, coating percent get its highest value on the Ksp condition near the reaction's equilibrium. As Ksp grow up, the Al2O3 'H2O self nucleated more. While coating TiOa, as Ksp grow up, the coating percent down. MxOy'nH2O that have same electronic properties (such as SiO2 ?nH2O, Al2O3 xH2O in alkali conditions ) can rarely deposit on the surface of graphite. When coating Al2O3, TiO2, Cr2O3, ZrO2, as coating volume up, the particle size of MxOy nH2O grow up. As temperature going up, the Al2O3 coating percent down. When use Ab(SO4)3, A1(NO3)3, AlCb as raw materials, it finds that Al2(SO4)3 coating percent is the lowest, but Al2O3 xH2O particle size is the biggest, AlCbjust contrariwise.The second is properties research on composite powders. Through the temperature differential analysis of composite powders in oxidation atmosphere, compared with untreated graphite, it reveals that after coating Al2Oa the peak temperature values of the reaction between graphite and oxygen/oxides going up, while after coating TiO2, Cr2O3, ZrO2 the peak temperature values going down. Compared with untreated graphite, all of the composite powders have decreased the contact angles with water, when Al2O3 coating volume up, the angle decrease also. After dispersed in water, all of the composite powders' Zeta-PH reliance is similar to the oxides it coated. In watercarbon/aluminum composite powders' sedimentation and rheological properties of its slurry are very different from untreated graphite. Its' sediment time is shorter than that of untreated graphite and the bulk density of sediments is higher. From it we can get the conclusion that its wettability with water and disperse in water have improved. The XRD results reveal the oxides coated are non-crystal and XPS results reveal it have chemical bonder with the surface of graphite.