Investigation Of Measuring Methods For Metal Aluminum Content In Aluminum Nanoparticles

The high reactivity Aluminum (Al) nanopowders were prepared by laser-induction complex heating technology. The Content of the Metallic Aluminum (CMA) in the Al nanopowders was characterized by a new chemical analysis method, which is the adaptation of the known permangantometric back titration method by the change of the Al nanopowders'dissolution condition and environment. The results is 20% higher than the conventional titration method. The change eliminates the by-reactions during the Al nanopowders dissolution process, and makes the analysis results more accurate than the conventional Al nanopowders chemical titration analysis method. More over, the chemical principles and the characteristics of Al nanopowders were used to account for the results. On the other hand, the thermal property and the reactivity dismissed at the different temperature of the Al nanopowders were analyzed by the TG-DTA results. The CMA results from the TG-DTA experiments data were compared to the chemical titration analysis. From this comparative, the chemical titration analysis method gets the better results than the results from the TG-DTA data, which illustrate that the usage of the changed redox titration method for the CMA characterization is reasonable and accurate. Not only the results from the changed chemical titration method better than the conventional titration method, but also better than the TG-DTA data.The XRD, SEM, TEM and HRTEM are used in the characterization of the peculiarity of the Al nanopowders in this paper. The results improved that the Al nanopowders'diameter is about 50nm, and it's apply to the normal school. From the TEM pictures, its notice that the surface of the non-coated Al nanopowders have been partly oxidized, which also proved by the XRD pattern.The CMA of the prepared Al nanopowders was characterized by the improved the Al nanopowders dissolution environment in conventional chemical titration method, which replaced the water by the ethanol as solvent to eliminate the by-reactions in the Al nanopowders dissolving process. The results showed that the ethanol replaced the water as the solvent is better for the CMA of the Al nanopowders characterization (75.19%). On the other hand, the added time and the volume of the dilute HNO3 solution are the other key points of the Al nanopowders dissolution in the chemical titration. The results illustrated that the accurate CMA can obtain only when the HNO3 added in appropriate volume (350ml/g) and time (24h). More over, the mechanism of the water, ethanol and dilute HNO3 solution is discussed in this paper.The thermogravimetry (TG) and Differential scanning calorimetry (DSC) apparatus were used to analyze the CMA (69.8%) and the thermal characteristic of the Al nanopowders. The results showed that the samples of Al nanopowders experienced different process in the thermal experiments due to different masses and temperature accelerated velocity. It's processing slow oxidation in low temperature accelerated velocity or low samples mass while occurring drastic combustion in the high temperature accelerated velocity and high samples mass. The mechanism of the Al nanopowders oxidation and combustion is discussed in the paper. Further more, the process of the Al nanopowders reactivity lost is also described.