Views:266 Author:Site Editor Publish Time: 2020-04-10 Origin:Site
There are many preparation methods of self-luminous materials, which are basically the same as those of general inorganic materials. In addition to gas phase synthesis, there are two main categories: solid phase synthesis and liquid phase synthesis.
The solid phase synthesis is a preparation method which mainly uses solid phase chemical reaction. In a broad sense, solid phase chemical reaction refers to the reaction with the participation of solid phase reactants. The liquid phase synthesis can be divided into conventional precipitation method, chemical coprecipitation method, hydrothermal synthesis, sol-gel method and combustion synthesis, they each have advantages and disadvantages. In general, the light storage and self-luminous materials with luminescence properties can be obtained by using different methods or controlling different conditions.
The preparation of self-luminous materials generally includes the basic processes of the purification of raw material, the preparation of predecessor, igniting and aftertreatment. The purification of raw material is mainly to remove heavy metal impurities from the raw materials. The basic methods for removing impurities are precipitation separation, extraction separation, ion exchange separation, chromatographic separation and so on. In the preparation of the self-luminous materials, operators often use chromatography to achieve the separation of impurities in the solution of rare earth ions and they generally use precipitation separation to purify other solutions. The principle of precipitation separation is to achieve the separation effect according to the different solubility of different substances in water or organic solvent. In addition, the purity of the water and other solvents, the cleanliness of the operating environment and the cleanliness of the utensils should be paid attention to during the whole process of the preparation of the self-luminous materials.
The preparation of predecessors is one of the key steps to obtain the self-luminous materials, and various synthesis methods can be used. In this process, the dosing is very important. The dosing means that the matrix, activator, flux and other necessary additives are mixed evenly in a certain proportion, and then treated as necessary to make raw materials for burning. The dosage of the activator is generally percentage of thousands of the matrix. The role of the flux is to accelerate the rate of solid phase reaction, reduce the reaction temperature, and effectively control the particle size of luminescent powder.
Burning is a key step in forming a luminescence center. The main function of burning is to allow the matrix to react chemically to form a solid melt. When the matrix has a certain crystal structure, the activator will enter the gap of the matrix lattice. In this step, the operator should control the burning mode, burning time, burning temperature to prevent the reactants from being oxidized.
The aftertreatment mainly includes the steps of powder selection, washing and sifting. This step is mainly to remove the flux in the product and other impurities produced during the burning process. First, the operator should remove the non-luminous parts, then remove the flux and the ions and other impurities that did not enter the lattice by water washing, and finally let the product pass through the filtration, drying, sifting steps in turn to obtain the self-luminous material.