Preparation of ultra-fine copper-zinc powder by thermal spraying technology

       

Preparation of ultra-fine copper-zinc powder by thermal spraying technology

Spraying refers to a series of processes in which fine and dispersed metallic or non-metallic coating materials are deposited on the surface of a prepared substrate in a molten or semi-melted state to form a sprayed deposition layer. It uses some kind of heat source (such as electric arc, plasma spraying or combustion flame, etc.) to heat powdered or filamentous metal or non-metallic materials to a molten or semi-molten state, and then spray it at a certain speed with the help of flame itself or compressed air The surface of the pretreated substrate is deposited to form a technology of surface coating with various functions. Combining thermal spraying method with mechanical ball milling method, a new preparation method of ultrafine copper-zinc powder is proposed.

 

Based on the conventional thermal spraying process parameters for powder preparation, the influence of ball milling time, ball milling aids, and heat treatment conditions on the properties of the powder was discussed, and the best preparation plan was obtained. The method can prepare ultrafine copper-zinc powder with uniform particle size distribution, stable properties, and particle size of 200-500nm. In view of the fact that the ultrafine copper and zinc powder agglomerated seriously in the liquid medium, the dispersion effect of the powder under the action of different dispersants was studied by the sedimentation method and spectrophotometry. The orthogonal test method was used to optimize the dispersant formula, analyze various factors that affect the dispersion performance, discuss the mechanism of various dispersants, and find the best conditions for different dispersants, thereby improving the ultrafine copper zinc powder Its dispersion stability provides an effective way to obtain ultrafine powder with stable properties.

 

The results show that the ball milling process and heat treatment parameters have an important influence on the properties of copper and zinc powder. In the initial stage, the particle size of the powder becomes larger with the increase of the milling time. When the milling continues, the particle size of the powder becomes smaller. After being refined to a certain degree, the particle size of the powder no longer changes significantly with the extension of the milling time. The addition of ball milling aids improves the efficiency of ball milling, improves the effect of ball milling, and significantly improves the dispersibility of the powder. After the heat treatment, the particle size of the powder increases, the proportion of fine particles decreases, and cracks appear on the surface, which reduces the hardness of the powder, and at the same time, the agglomeration effect of the powder is weakened.