Knowledge about flake silver powder and grinding aids

The properties of flake silver powder are stable, and the particles are in surface or line contact, so the resistance is relatively low and the conductivity is good. Flake silver powder is one of the important materials for electronic components, and is widely used in electronic components such as membrane switches, filters, carbon film potentiometers, silver nanoparticles tantalum capacitors, and semiconductor chip bonding.

 

The key process for preparing flake silver powder is ball milling. The process of ball milling is more complicated. The quality of flake silver powder’s micro morphology, diameter-to-thickness ratio, and surface condition all depend on the ball milling process. The main influencing factors of ball milling include ball gradation, ball mill speed, ball-to-material ratio, ball milling time, type and amount of grinding aids, ball milling atmosphere, ball milling temperature and so on.

 

Different ball milling aids have different effects on the performance of the powder. If only absolute ethanol is used as the wet milling medium, the prepared silver powder particles are coarser and the silver flakes are larger, but they are very bright. Using oleic acid as the ball milling medium, the prepared powder is better in flakes and the color is silver gray. Using stearic acid as the ball milling medium, the prepared silver powder has a flake size and the color is silver gray. The color of the silver powder prepared by the compound auxiliary agent is bright gray.

 

The so-called grinding aids are chemical substances that can significantly improve the efficiency of crushing operations and reduce the energy consumption per unit of product. It includes organic and inorganic matters. The main purpose of adding a grinding aid is to improve the grindability of the material, reduce the interaction between particles and the adhesion of fine particles on the grinding medium, and provide the fluidity of the material in the mill, thereby improving the fineness and quality of the product.

 

There are mainly two views on the mechanism of action of grinding aids. One is the theory of “adsorption reduces hardness”, which believes that the adsorption of grinding aid molecules on particles reduces the surface energy of the particles or causes dislocations in the crystal lattice near the surface layer, thereby reducing the strength and hardness of the particles. The second is the theory of “pulp rheology adjustment”, which believes that the grinding aid reduces the viscosity of the pulp and promotes the dispersion of the particles by adjusting the rheological properties of the pulp and the surface electrical properties of the mineral particles. Both theories explain the mechanism of the grinding aid from a certain aspect, but the grinding aid acts on the powder in a highly complex ball milling environment, so it should be considered comprehensively.

 

According to experiments, the amount of ball milling aids added has a great relationship with the bulk density. With the increase in the amount of ball milling aids, the bulk density of the powder continues to decrease. When the amount of ball milling aids is over 1.5%, the bulk density of the powder gradually increases, so the amount of ball milling aids can be considered to be controlled around 1.5%.

 

Hongwu Nano produces flake silver powder with low bulk density and normal bulk density. In addition, customers for different applications have different requirements for whether to wash off the grinding aids, and we can deal with them accordingly. Get nano silver price from us quickly!