Plasma treatment to improve the quality of nano bismuth oxide

Bismuth oxide is an important functional powder material, widely used in inorganic synthesis, electronic ceramics, chemical reagents and other fields, mainly used in the manufacture of ceramic dielectric vessels, can also be used in the manufacture of piezoelectric ceramics, varistors and other electronic ceramic components.

Due to the finer particle size of nanometer bismuth oxide, in addition to the properties and applications of bismuth oxide powder with general particle size, it can also be used in occasions with special particle size requirements, such as electronic materials, superconducting materials, special functional ceramic materials, cathode-ray tube inner wall coating, etc.
Therefore, the exploration of preparation method and application of nano Bi:O3 has aroused extensive interest of researchers at home and abroad.

Nano-Bi20 was prepared by solid-state reaction method, precipitation method, spray combustion method, sol-gel method, etc. These methods have achieved good results, but there are still some limitations: the particle size of nano bismuth oxide prepared by spray combustion method is not uniform and requires higher equipment; Nanometer bismuth oxide produced by chemical method is easy to agglomerate. Due to the use of alkali solution in the production process, alkali metal or alkali earth metal ions are inevitably brought into the production process, which affects the purity of bismuth oxide.

Plasma is active, it is in the ionized state of gaseous material, is a gas phase of chemical reaction. Plasma is produced by ionization of pure gas, which is beneficial to the preparation of high purity powders.

Due to the large temperature gradient of plasma, it is easy to obtain high saturation, and also easy to achieve rapid quenching and obtain high purity nano powders. Compared with liquid phase method, the powder prepared by gas phase method generally has high purity, clean surface, good crystalline structure and less environmental pollution. Therefore, it is more advantageous to use gas phase method when preparing bismuth nano powder.
The preparation of nano powders by plasma method has many advantages that other methods do not have. Using ordinary micron-sized nano-bismuth oxide powder as raw material, and by selecting appropriate power and dosage, the tetragonic-system nano-BizO3 powder with a median particle size of 17.5nm and a specific surface area of 47.73m/g was successfully prepared by using plasma as heat source. The prepared nanometer bismuth oxide has high purity and good crystal structure.