The research of nano alumina has attracted great attention at home and abroad, and its preparation methods can be divided into solid phase method, liquid phase method and gas phase method.
1. Solid phase method
The use of solid-phase method to prepare nanomaterials refers to a process of changing from solid phase to solid phase. The final powder and the original raw material can be the same substance or different substances. The solid-phase method can be divided into two categories: one is the topdown approach, which refers to the separation of larger particles into smaller particles by mechanical force or other forces. In this process, the powder The particle size of the body is constantly decreasing. The other is the bottom up approach, which refers to the process of recombining the smallest unit (atoms or molecules) through diffusion, which is relatively slow.
2. Gas phase method
The gas phase method is a method that uses a certain way or directly uses the material to turn into a gas, reacts in the gas phase, and aggregates to form nanoparticles during the cooling process. The advantage of the gas phase method is that the reaction conditions are controllable, and nano alumina particles with a smaller particle size and a lighter degree of agglomeration can be obtained by controlling the reaction gas and pressure. However, this method needs to react in the gas phase. Therefore, the raw materials must be completely vaporized before the reaction occurs. This inevitably causes energy loss and waste. A large amount of inert gas is required during the preparation process, and the production efficiency is low. The equipment of the method is relatively large and complicated, and the final powder is difficult to collect.
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