Electrode erosion by particle ejection in low-current arcs

Abstract

A theory for the cathode mechanism in lowcurrent vacuum arcs, with application to the calculation of erosion rate

Nano-droplet ejection and nucleation of materials submitted to non-thermal plasma filaments

“…Indeed, micro-droplet ejection has been observed from thermal sparks filaments with energy and diameters higher than those of prevented spark discharge filaments. This has been attributed to the recoil force from the solid bottom of the micron-sized crater on melted metal [23]. These spherical solidified drops are much less concentrated than the primary nucleated nano-particles and agglomerates, since there is no shoulder in this size range on the related size distribution of Figure 3a produced by prevented spark discharge, where the modal diameter is related to agglomerates.…”

“…Figure 6 : (a) TEM micrograph of craters formed for 1 (upper) and 60min (lower) of prevented spark discharges on silver electrode; (b) Mechanisms of nucleation/agglomeration and droplet ejection from melted craters formed in spots of interaction between prevented spark discharge and electrode [22][23].…”

Influence of the inter-electrode distance on the production of nanoparticles by means of atmospheric pressure inert gas dc glow discharge

“…Then, a metal vapour jet is produced by the cathode surface itself and by a cloud of metal microdroplets released from the cathode surface and evaporating during the flow. The explosive ejection of spherical submicron particles (0.1-1 µm) from the cathode has been commonly observed in atmospheric pressure glow and low current arcs; the phenomenon (cathode jet) has been investigated experimentally [16,17] and numerically [18][19][20].…”

Measurement of the amount of liquid and vapour created by an electric arc on an electrode – case of Ag and AgSnO2electrodes

“…In [4] it was explained that the radial ejection is due to the action of the arc pressure on the liquid metal. In [3], the axial ejection of liquid metal is caused by the stop of ionic forces at the end of the arc. In [7] the authors have considered the action of other forces: during the arc, the melted metal may be submitted to intense forces (Lorentz forces or forces resulting from a superficial strain gradient).…”

“…An unknown part of liquid metal may remain on the electrode surface and solidify after the end of the arc. 3 The aim of this study was the experimental determination of the amount of liquid and vapour of electrode metal created by a non stationary electric arc burning at atmospheric pressure in air. This determination presents a double interest:…”