The Numerical and Experimental Investigation of Particle Size Distribution Produced by an Electrical Discharge Process.

Faming Lin,Xianglong Li,Congqiang Bai,Yifan Liu

doi:10.3390/ma14020287

Abstract

The vague influence of thermal action of electrical discharge on size distribution of metallic powders hinders the adjustability of powder quality. Due to the small gap, short discharge on-time, uncertain discharge point, and strong light interference, direct observation of preparation is difficult to carry out. Herein, the multi-physics coupling finite element method (FEM) was applied to numerically investigate the relationship between size distribution and thermal action. Through modeling of thermal transformation and heat distribution on the surface of electrode, temperature of the electrode is found to be decided by the latent heat and the distribution of heat point obeys the normal distribution, which corresponds with experimental results. Finally, the vapor film to droplet fragmentation theory was proposed to explain the phenomenon of normal distribution. The research results provide theoretical support for the preparation of metallic powder by electrical discharge, and also play a guiding role in optimizing the process parameters in the actual preparation process to tune the size distribution.

Highlights

Metallic powders have been rapidly increasing in various fields such as science and engineering areas because of their remarkable physical and chemical properties compared to their corresponding bulk materials
As one of the cost, green, efficiency, and productivity approaches, the electrical discharge method is widely applied in preparing the metallic powders due to the simple physical phase change from solid to molten and molten to solid
The thermal action of electrodes was affected by latent heat during the heating process

Summary

Introduction

Metallic powders have been rapidly increasing in various fields such as science and engineering areas because of their remarkable physical and chemical properties compared to their corresponding bulk materials. Ag nanoparticles were synthesized by arc discharge in a solution such as H2O, ethanol (C2H5OH), and water mixed aqueous solution of polyvinyl pyrrolidone (PVP) with a corresponding average particle size of 8, 10, and 13 nm [8,9]. Spherical Zr nanoparticles are synthesized via electrical discharge with average size decreasing from 40 to 22 nm by increasing the current from 40 to 160 A [10]. M. Mardanian et al [15] used a high voltage AC power supply (current of 60 A with a high voltage of 8.5 kV at about 100 Hz frequency) to create a pulsed spark discharge with a pulse duration of 30 μs to produce CuInSe2 nanoparticles in ethanol (C2H5OH). The nickel powder particle size distribution is related to energy input and the ultrasonic power. The theorical research was not developed to build the relationship between energy input and size distribution

Methods

Results

Conclusion