The Synthesis Of Alumina Nanoparticles And Its Modification

Alumina nanoparticles have wide application because of its characteristic such as high temperature resistance, high hardness, high strength and electrical conductivity and so on. There are lots of research and literature report about nano alumina. In this paper, the synthesis method of nano aluminium oxide by hydrothermal method with aluminum sulfate as raw material was studied. By changing the pH of the reaction solution, reaction time and reaction temperature and so on, the products of different traits can be produced, the characteristics of particle size, SEM, FTIR and so on were also carried out. The effects of different reaction conditions on the crystal form, morphology and particle size of nano alumina were studied. The optimum reaction temperature of nano alumina prepared by hydrothermal method was 180. Under this condition, the particle size of the nano alumina can be minimized, and the agglomeration is relatively light. Effect of reaction time on the particle of the product is time from 4h to 10h, the particle size of the nano alumina change trend is not obvious, under the specific temperature (160℃,180℃ and 200℃), reaction time 4h and 6h, the product particles smaller, more dispersed. The optimum conditions for preparing nano alumina by hydrothermal method were obtained:pH was 9, temperature was 180"C, reaction time was 4h. Then, the application of nano alumina prepared by different methods was discussed. Preparation of good crystallinity α-Al2O3 is by hydrothermal reaction. α-Al2O3 plays an important role in coating. And the size of α-Al2O3 is smaller, the performance of the coating is better. Finally, in order to reduce the particle size of nano alumina and to change the aggregation of the product, the nano alumina precursor was modified by different modifiers and by dry and wet methods. Aluminate coupling agent is beneficial to the preparation of nano alumina which with smaller particle size and lighter agglomeration; Modification of silane coupling agent, the change of particle size and aggregation of the product is not obvious; Stearic acid is beneficial to reduce the particle size of the product. Compared with the dry method, the effect of wet modification is better.