Detonation Synthesis Of Nanometer Alumina And Control Study About Its Phase And Dimension

Nanomaterials made up of solid particles with the size of (1-100) run have developed up to a new type of solid materials since the 1980's. Thanks to well-known surface effects, volume effects, quantum dimension effects and macroscopical quantum tunnel effects, nanomaterials are extensively used in many fields such as material, mechanism, chemical industry, medicine and military affairs, etc. Thereinto, nanometer alumina is of so many characters like high rigidity, high intensity, heat-resistance and corrosion-resistance, etc, and is used widely in fine ceram, composite material and activator, etc. Because of the extensive applications of nanometer alumina, it is necessary to search a convenient and speedy method to produce it. In addition, compared with its research of application and manufacture methods, the preparations of nanometer alumina powders are developed slowly. For example, there are still a lot of technique and engineering problems in control nanodimension and phases of nanometer alumina, and preventing nanogranule to congregate, etc. Aiming at the problems above, two ideas of research are presented in this paper. One is to search a new method with low cost and high yield to prepare nanometer alumina, and the other one is to realize man-made control nanodimension and phases of nanometer alumina during the preparation.At the beginning, this article summarizes the current developments of nanometer alumina in three aspects of the applications, the methods of preparation with different characters and the problems existing in technique of preparation. Further more, a new method to prepare nanometer alumina by low-cost material of aluminum nitrate or aluminum hydroxide through detonation of RDX is presented, which is also called detonation synthesis. Nanometer alumina powders with different dimensions, shapes and phases are prepared by detonation synthesis. And the relations between the mixed explosives with different parameters and the phases, and the nanodimensions of nanometer alumina resulted from the explosives are studied by the means of experiments, calculations and experimental detections. Finally, the characters of low temperatures calcinations of nanometer alumina with different phases are introduced. The main research results of this paper are as follows:(1) Based on the characters of different preparation methods and the problems in the technology of nanometer alumina, a new method called detonation synthesis is presented. The method has advantages in fast synthesis, simple technology process, low-cost equipment and amplificatory yield. In addition, the method itself has the characteristics of vapor phasecomposition, so that it is of technical advantage to synthesize high-dispersing and high-purity nanometer alumina.(2) The spherical nanometer y alumina, spherical nanometer a alumina, lamellar nanometer a alumina and spherical nanometer mixing phases alumina are successfully synthesized by the detonation method.(3) From the study of nanometer alumina with different shapes and phases synthesized by detonation, the special series of explosives used for detonation synthesis and their manufacturing methods (such as loading powder with pressure, water gel) are obtained, for instance, the special explosive of aluminum nitrate and its manufacturing method, the special explosive of aluminum hydroxide and its manufacturing method, etc. Moreover, aiming at the pollution caused by poisonous gas released during the detonation, the balance of oxygen of explosive is researched. The result indicates that by adding the suitable substance of balance of oxygen into the explosive, little poisonous gas or nothing could be released during the preparation of nanometer alumina. Consequently, the pollution can be solved.(4) Aiming at the shortcoming of technique on control synthesis of nanomaterial, the relations between different parameters (such as density of explosive, temperature of explosion, velocity of explosion and press of explosion etc) of special series of explosives used for detonation synthesis and phases and nanodimensions of nanometer alumina are chiefly studied. The corresponding relations are described by experiments, calculations and experimental detections.(5) The characters of low temperatures calcinations of nanometer alumina with different phases are characterized by XRD and curves between dimensions of crystal grains and calcination temperatures. The results indicate the calcination characters of nanometer alumina with different phases differ from high temperatures calcination.In a word, several studies and the innovations in this paper are presented on the base of the current study of nanometer alumina, and the research results are obtained, which are expected to be possibly helpful as reference in this field in the future.