Preparation Of Superfine Powder Materials CuMoO₄-MoO₃and Li₄Ti₅O₁₂

Cu-Mo alloy, a kind of composite material with combination of the excellent performance of Cu and Mo, has been widely used in the fields of electronic packaging materials, electrical contact materials and so on. But with the development of modern high-tech, the Cu-Mo alloy with high density and low gas content is urgently required. Powder metallurgy technology is widely conducted to prepare Cu-Mo alloy, and the quality of alloy is highly influenced by CUMoO4-MoO3powders.CUMoO4-MoO3powders were prepared by sol-gel method with ammonium heptamolybdate, copper nitrate and citric acid, and ammonia was used to adjust the pH value. TG-DTA, XRD, SEM, EDX and FT-TR experiment methods were employed to characterize the dried gels and powders calcined at different temperature. The influence of pH value was also studied. Results showed that the precursor powders calcined at500℃for2h exhibited completely crystallinity, high distribution and no significant aggregation when pH value was8.0to9.0.CUMoO4-MoO3powders were also synthesized through solid state method with ammonium heptamolybdate and copper nitrate. The influence of calcined temperature on the characterization of the powders was studied by TG-DTA, XRD, SEM, EDX and FT-IR experiment methods. Results showed that the precursor powders calcined at400℃for2h exhibited completely crystallinity and high distribution without significant aggregation. Compared with sol-gel method, the price of solid state method was relatively low.Nowdays, Li-ion battery materials play an important role due to the highly requirement of energy. Compared with carbon anode material, Li4Ti5O12, a kind of spinel-structured negative electrode material, has several advantages, such as zero strain or volume change during the charge-discharge process and higher flat working voltage1.5V vs.Li which avoids dendritic lithium ion growth. Therefore, this material is regarded as one of the most promising anode materials.Li4Ti5O12powders were obtained through high temperature mechanochemistry technology with lithium carbonate and metatitanic acid. XRD, SEM and PSD methods were utilized to analyze the influence factors on this processing, such as ball milling temperature, time and molar ratio of Li and Ti. Results showed that Li4Ti5O12powders acquired at700℃for3h with molar ratio Li:Ti was0.88showed high distribution without significant aggregation, and the particle size was between200～350nm. The first discharge specific capacity at0.5C was132.6mAh·g-1. High temperature mechanochemistry reduced the reaction temperature, furthermore, avoided the aggregation.