RU2537383C2 - Method of channels creation in electrode in dependent arc discharge - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: between electrodes at fixed distance from them voltage is supplied, the created current melts and evaporates thin wire located between the electrodes. Distance from the cathode to anode is selected such that discharge without wire can not occur inadvertently, and between electrodes there are conditions for avalanche breakdown of the discharge gap creating upon presence in air of the evaporated wire vapours. At that one wire end is in hole inside the cathode surface and touches it, upon voltage supply to the discharge gap from the wire and cathode surface contact point in the cathode the channel is created initiating from the contact point in direction from the connection place of the cathode with negative voltage source pole.

EFFECT: creation of channels in cathode in dependent arc discharge thus increasing efficiency of scientific researches of microelectronics technology.

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Description

The invention relates to the field of studying the physical properties of a substance, in particular to studying processes in a plasma and in gas-discharge devices, between which the voltage is applied between the anode and cathode at a fixed distance between them. The resulting current melts and evaporates a thin wire that is placed between the electrodes in contact with them. The distance between the electrodes is chosen so that a discharge without a wire does not occur. Between the electrodes, conditions are created for avalanche breakdown of the discharge gap arising in the presence of vapor of an evaporating wire in the air. In this case, one end of the wire is located in the hole inside the cathode surface and touches it, and when voltage is applied to the discharge gap, a channel is formed from the point of contact of the wire and the cathode surface on the cathode, coming from the point of contact in the direction from the junction of the cathode to the negative pole of the voltage source.

The technical result of the invention is the development of a method of forming channels on the surface of the cathode in a non-self-sustaining arc discharge.

A known method of ignition of an arc discharge when voltage is applied to it due to the initial close contact of the electrodes moving relative to each other with their subsequent extension [1].

This method does not allow igniting a non-self-sustaining arc discharge.

A known method of ignition of a non-self-sustaining arc discharge in the discharge gap with a metal wire between the electrodes [2].

This method does not allow the formation of channels on the surface of the cathode.

The technical problem solved in the proposed invention is to develop a method for creating on the surface of the cathode channels in a non-self-sustaining arc discharge by evaporation of the wire inside the discharge gap. Its essence is as follows. One of the ends of the wire placed between the electrodes is located in the hole inside the cathode surface and touches it. When voltage is applied to the discharge gap from the point of contact of the wire of the cathode surface, a channel is formed on the cathode, proceeding from the point of contact in the direction from the junction of the cathode with the negative pole of the voltage source.

The task is achieved by the fact that between the anode and cathode at a fixed distance between them, a thin metal wire melts and evaporates. In this case, one end of the wire is located in the hole inside the cathode surface and touches it, and when voltage is applied to the discharge gap, a channel is formed from the point of contact of the wire and the cathode surface on the cathode, coming from the point of contact in the direction from the junction of the cathode to the negative pole of the voltage source.

This method for the first time makes it possible to form channels on the cathode surface in a non-self-sustaining arc discharge during evaporation of the wire inside the discharge gap, one of the ends of which is placed in the hole on the cathode surface.

The essence of the method is as follows. A voltage is applied between the metal electrodes at a fixed distance between them. The resulting current melts and evaporates a thin wire that is placed between the electrodes, while the distance between the electrodes is chosen so that a gas discharge without a wire is not ignited, and conditions are created between the electrodes for avalanche breakdown of the discharge gap arising in the presence of vapor of the evaporating wire in the air. At the same time, one end of the wire is located in the hole inside the cathode surface and touches it, and when voltage is applied to the electrodes from the point of contact of the wire and the cathode surface, a channel is formed on the cathode coming from the point of contact in the direction from the junction of the cathode to the negative pole of the voltage source.

The scheme of the method is shown in the drawing (see Fig. 1). The wire 1 is stretched between the cathode (2) and the anode (3) and is in contact with them. In this case, one end of the wire is in contact with the cathode surface inside the hole (4) in the cathode. To supply voltage to the electrodes, the Dolphin rectifier unit (5) with a rectified voltage of 220 V was used. The discharge current at a maximum was varied in the range of 10–50 A using an alternating resistance (6). The discharge duration is about 0.1 second. Various metals (Cu, Ni, Fe, Ti, brass, stainless steel and others) were used as cathodes. We took wires of various metals and alloys (Cu, Ni, Fe, nichrome, Kovar, and others). The diameter of the wires varied in the range of 0.04-0.1 mm, their length varied from 15 to 30 mm.

When voltage is applied to the discharge gap with a wire stretched between the electrodes, a channel is formed from the point of contact of the wire and the cathode surface on the cathode under the action of cathode electrons and ions (7). A photograph of it on a transformer iron cathode plate is shown in Fig. 2. Channel (7) comes from the hole in the cathode (4) in the direction from the junction of the cathode with the negative pole of the voltage source (8) towards a more positive potential.

We draw attention to a number of circumstances.

1. The channel at the cathode, like gas breakdown, does not occur without a wire, since the breakdown voltage of a discharge gap 1 cm long in air at atmospheric pressure is 31000 V [3].

2. When the wire is located at the end of the cathode plate (see Fig. 1 in [4] on page 4), channels do not arise.

3. The length of the channels is 1-3 cm.

4. With each subsequent breakdown of the discharge gap, the channel lengthens for 5-6 gas breakdowns, after which its length ceases to change. In this case, the channel has a trajectory fixed on the cathode surface. This circumstance suggests that the conductivity of the metal at the cathode inside the channel may be greater than outside the channel.

5. The channel can be formed by touching the surface of the cathode with one of the ends of a thin wire, while its second end is fixed to a movable anode. However, in this case, the channels from breakdown to breakdown differ from each other due to the different contact conditions of the wire with the cathode.

The appearance of channels in a metal can be explained on the basis of the principle of the least action of electrodynamics [5] for an electric current flowing through a mass of a substance whose resistance satisfies Ohm's law, currents are distributed in this mass so that the rate of heat generation in it is the lowest. Hence, we can assume that the channel is the trajectory of the movement of electrons in the metal along which the energy losses for heating are minimal, i.e. the channel is the trajectory with the highest electronic conductivity. That is why electrons during each subsequent breakdown move along a trajectory that coincides with the trajectories of previous breakdowns.

Thus, in the proposed method, for the first time, a solution is given to the formation of channels on the cathode in a non-self-contained gas discharge with a metal wire between the electrodes, one of the ends of which is located in the hole inside the cathode surface and touches it.

The method is simple to implement and effective. It can be used in engineering and in scientific research, for example, in new microelectronics technologies.

Information sources

1. Theory of welding processes, editor VV Frolov. M .: Higher school, 1988.

2. R.N. Kuzmin, N.A. Miskinova, B.N. Shvilkin. Patent for invention No. 2388192. 2010.

3. Radiophysical electronics, editor N.A. Kaptsov. MSU Publishing House, 1960, p. 497.

4. R.N. Kuzmin, N.A. Miskinova, B.N. Shvilkin. Patent for invention No. 2368472. 2009.

5. R. Feynman, R. Leighton, M. Sands. Feynman lectures in physics. T. 6. Electrodynamics. Publishing house "Mir". 1962, p. 117.

Claims (1)

A method of forming channels on the cathode in a non-self-contained arc discharge, in which a voltage is applied between the electrodes with a fixed distance between them, the resulting current melts and evaporates a thin wire that is placed between the electrodes, while the distance between the electrodes is chosen so that the discharge does not spontaneously without wire ignites, and conditions are created between the electrodes for avalanche breakdown of the discharge gap arising in the presence of vapor of an evaporating wire in the air, which differs it, that the wire is located in a bore inside the cathode surface and touches it, and when a voltage is applied to the discharge gap of the tangency point of the wire and the cathodic surface is formed on the cathode channel emanating from the touch point in a direction from the place of cathode connections with the negative pole of the voltage source.

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