Research on Surface Decoration Technology Based on Electrical Explosion Plasma Composite Jet

Surface enhancement by thermal plasma spray is an effective way to improve material properties. However, both inductively coupled plasma (ICP) and arc plasma torches rely on a large driving power supply, gas supply, feed and cooling system. In this paper, we propose an electrical-explosion-based spraying (EES) technology in pulsed operation mode, which realizes one-step surface modification and modulation of micro-nano-structures of materials under atmospheric environment. A directional spraying electrical explosion load is designed to deposit hundreds of Joules of electric energy within a small cavity of several cm³ to form a mixed metal-plasma-microparticle composite jet along a pre-positioned nozzle to treat the material surface. In the experiments, copper wire electrical explosion is used as a source of metal plasma and diamond powder is mixed with it to achieve directional spraying to modify the surface structure of silicon wafers. The discharge voltage and current were measured during the process, and time-resolved images of the electrical explosive spraying were recorded with a high-speed video camera. Scanning electron microscopy (SEM) and energy spectrometry (EDS) were used to characterize the surface morphology and components of the coatings in a materialistic manner. On the functional side, the water contact angle of the coatings was determined, and it was found that the micro- and nano-scale topographical features of the sprayed layers obtained by changing the scale and type of powder also change, resulting in differences in the water contact angle. The study expands the applications related to the preparation of functional materials by plasma at atmospheric pressure.