Evolution of anodic erosion components and heat transfer efficiency for W and W₈₀Ag₂₀ in atmospheric-pressure arcs

Abstract

Based on the in situ diagnostic system and the digital image post-processing technique, quantifications of the anodic erosion components and heat transfer efficiency for tungsten and the W 80 Ag 20 material in arcs of argon, helium, and nitrogen were achieved. The leading vaporization of silver has been found to result in evidently lower anodic heat transfer efficiency and much smaller molten pools compared with those of the tungsten anode, but the intensive generation of silver vapor under the melt layer causes higher splashing erosion of the W 80 Ag 20 anode. However, these characteristics can be strongly changed by the cathodic blowing, which leads to a much higher splashing erosion of tungsten anode but a lower erosion rate of W 80 Ag 20 anode. Through the visualization of the erosion behavior and the post microanalysis of the anode surface, the possible driving mechanisms for the generation of the splashing droplet were discussed. The result indicates that the local high pressure caused by the vapor blasting during the bubble explosion plays a key role in the detachment of splashing droplets. Furthermore, as for the tungsten-based anode, the comparison of erosion behavior between the W 80 Ag 20 anode and the previous-studied W 70 Cu 30 anode makes it clear that increasing the temperature difference between the melting point (MP) of tungsten and the boiling point (BP) of the other material has the pros and cons. It is effective for the decrease of the anode erosion when the anode heat energy is relatively weak, while it can promote the splashing erosion when the liquid tungsten layer has been formed on the anode tip. These results are beneficial for the optimal design of the electrode system in circuit breakers.

Study on arc duration and erosion characteristics of cable electrodes in AC series circuits

“…Through an in situ diagnostic system including surface temperature measurement and the fast imaging of the erosion process, Cui et al [35] found that the surface bubble explosion stemming from the Cu vapor inside the liquid tungsten layer is the main cause of splashing erosion of the W 70 Cu 30 anode, and the transition from evaporation-dominated mode to splashdominated mode is determined by the large difference between W and Cu in melting and boiling temperatures. The arc erosion characteristics of W 80 Ag 20 anode and pure tungsten anode are compared, and the results showed that W 80 Ag 20 anodes have lower anodic heat transfer efficiency, smaller molten pools, and higher splashing erosion owing to leading vaporization of silver [41]. Similar results were found in Mo 0.78 Cu 0.22 cathode under a DC vacuum arc discharge [42].…”

Quasi-Continuous Network Structure Greatly Improved the Anti-Arc-Erosion Capability of Ag/Y2O3 Electrical Contacts

“…Then, the positive ions bombard the cathode, resulting in the jet of the cathode material. These materials are transferred to the anode along with the electron flow [ 42 ]. The crater and protrusion are the products of this material transfer process ( Figure S3b ).…”

Green and Rapid Preparation of Fluorosilicone Rubber Foam Materials with Tunable Chemical Resistance for Efficient Oil–Water Separation

“…As is well-known, the fluorine-containing groups (e.g., −CH 2 CH 2 CF 3 ) with high polarity could reduce the material's surface energy, and they thus are usually used to incorporate into the polysiloxanes to improve the material's chemical resistance in both nonpolar solvents and oils [31]. Previous studies have demonstrated that the chemical resistance of traditional silicone rubber could be enhanced by the partial replacement of methyl groups with some fluorine groups [32]; for example, fluorosilicone rubber [33][34][35]. However, there are few reports about the preparation of fluorosilicone rubber foam materials.…”