Neutral Copper Gas Resistivity Measurements by Means of an Exploding Wire in Air

Abstract

Abstract:In this work, we present experimentally obtained limits for the values of the neutral copper gas electrical resistivity as a function of the temperature. When a current of about ≈ 10 3 A or larger flows through a metallic wire in a microsecond or shorter time, the wire performs a phase change from solid to plasma, through intermediate states of metallic liquid and vapor. If the wire is surrounded by a non-conductive dense medium that inhibits the circulation of current outside the wire (e.g., air at room temperature and standard pressure, as in our experiments), the electric current stops when part of the metallic wire becomes gas. This process is known as dark pause, and it has a duration that depends on the experiment parameters. By means of a suitable choice of parameters, we achieved a duration of the dark pause of ≈1 µs, which allowed us to determine the limits of the electrical resistivity of the metallic gas. The range of measured values starts from the resistivity of liquid copper at boiling temperature, and goes up to ≈0.01 (±20%) Ohm·m at the maximum measured temperature.

Slow energy deposition in an exploding wire and plasma evolution for longer times than the electrical discharge time

“…At present, they have a promising future as an alternative method to generate metallic powders of industrial interest [4,5]. On the other hand, it is also used in pure scientific endeavours, as the cylindrical shock waves studies of Bennett in 1958 [6] or more recent applications, like the first experimental results on copper gas resistivity limits [7].…”

Experimental Determination of the Resistivity Limits for Platinum and Iron Metal Gases Using an Exploding Wire

“…Considering that both temperature and number of moles of the gas monotonically increase with time during the dark pause, a first approach for evaluating the upper limit of the resistivity, given by (2), is by assuming a linear dependence with time. This approximation holds true within 20% according to numerical simulations [16]. The result of the measurement of the resistivity limits of iron and platinum are plotted in Figures 5 and 6.…”

“…On the contrary, to the knowledge of the authors, there are no experimental data published on the resistivity of metal gases such as iron and platinum. In this work, following the method developed for an exploding wire setup by the authors [15], and previously used to measure the resistivity limits of copper metal gas [16], further measurements of resistivity limits for gases of iron and platinum are presented.…”

“…In the experimental conditions described in [15,16], a neutral classical gas is formed with energy density of few hundreds of kJ per mol and pressure below 100 atm, that expands against the surrounding air. Under this condition, the gas phase grows at the expense of the self-heating solid-liquid core, a process well described in previous works [17,18].…”

Energy-load Matching and Shockwave Analysis of Electrical Explosion

“…The resistivity of Neutral Copper Gas is measured by the dark pause effect in a wire explosion [5]. Meanwhile, the weakening effects of water resistivity and phase state on underwater electric explosion are also studied [6,7].…”