RU2087982C1 - Material for heavy-current electronic device cathode - Google Patents

Abstract

FIELD: emissive electronics; electron sources for miscellaneous electronic devices. SUBSTANCE: material that has in its composition cesium or rubidium aluminosilicate and nickel is doped, in addition, with activator in following proportion, mass percent: cesium or rubidium aluminosilicate - 0.5-25; activator - 0.1-10; nickel - the rest. Titanium, zirconium, alkali-earth metal, their alloys and compounds may be used as activators. EFFECT: improved properties of material. 2 cl, 1 dwg

Description

 The invention relates to the field of emission electronics, in particular to the composition of the cathode material, which can be used as an electron source in various types of electronic devices.

 Known material for the cathode of electronic devices containing aluminosilicate of cesium or rubidium, as well as Nickel and consisting of an alloy or a mixture of powders of these components in the following ratio, wt.

cesium or rubidium aluminosilicate 0.5 25
nickel rest
(see A.S. N1115619, class HO1J 1/14).

 The disadvantages of the above cathodes include low emission stability due to the low resistance to ion bombardment of the cathode surface, in the absence of additional activations, the cathode surface is depleted in cesium, which increases the work function. The restoration of the cesium film on the cathode surface is possible due to thermal activation.

 This disadvantage poses the problem of creating material for the cathode of electronic devices, providing increased emission stability in a wide range of operating conditions.

 The objective of the invention is to increase emission stability in a wide range of operating conditions.

 This technical problem is achieved by the fact that the activator is additionally introduced into the material for the cathode of electronic devices containing cesium or rubidium aluminosilicate and nickel in the following ratio, wt.

Cesium or rubidium aluminum silicate 0.5 25
Activator 0.1 10
Nickel rest
It is known that during the passage of powerful current pulses in electronic devices, for example, in protective arresters, the cathode surface is depleted in material with a small work function and the parameters of the devices change dramatically.

 The introduction of the activator contributes to the formation and maintenance of a stable alkali metal film both on the surface and in the volume of the cathode due to the reduction reaction of the latter by the activator.

 The activator may be titanium, zirconium, SCHM, their alloys and compounds.

 The cathodes of the materials of the proposed composition are a mixture of the powders of these components, are made by any known method: applying this mixture to the substrate, rubbing the paste, spraying the suspension, pressing the mixture, followed by sintering in a vacuum or protective medium on a metal substrate, and pressing with further fixing on electrode by soldering or sintering the intermediate paste.

 To test the action of the activator, a prototype of a gas-discharge uncontrolled spark gap with argon filling and a distance between the electrodes of 0.5 mm was chosen.

 The models were tested in a pulsed mode (one of the protection modes of the telephone exchange), current 10 kA. The criterion was the static gap breakdown voltage, since it mainly depends on the cathode activity (work function). The cathodes were prepared by pressing nickel powder and the active composition of the tablet, followed by sintering at a temperature of 1200 K in a furnace with a protective medium (argon, thermal activation).

 Before the test, 3 pulses with an amplitude of 10 A, a frequency of 50 Hz, and a duration of 1 s were applied to train the cathode surface.

 As an example, cathodes consisting of cesium aluminosilicate, nickel, and BaCu alloy activator (90/10) are given.

 The percentage mass was selected from the net weight of barium in the alloy. The results of the experiment are given in table. one.

 The percentage of activator and cesium aluminosilicate is taken from experimental data. It was noted that when the activator content is less than 0.1%, the stabilization effect is not observed, which is obviously due to its insufficient distribution over the cathode body. When the content of aluminosilicate is more than 10%, a decrease in the strength of the cathode pellets was observed on the one hand, and on the other hand, some reactivation of the cathode during manufacturing was possible, which reduces the stabilization effect.

 Thus, this material ensures the stable operation of the cathodes made from it under conditions of intense ion bombardment and has a sufficiently high emissivity.

 Thanks to this, the use of this material will expand the range of operating modes.

 The above advantages of the invention were identified by the results obtained during testing at the enterprise.

 The invention has been brought to industrial use and serial production will begin in August 1995.

Claims (1)

 1. Material for the cathode of high-current electronic devices, containing cesium or rubidium aluminosilicate and nickel, characterized in that it additionally contains an activator in the following ratio of components, wt. Cesium or rubidium aluminum silicate 0.5 25
Activator 0.1 10
Nickel Else
2. The material according to claim 1, characterized in that one of the materials of the group consisting of titanium, zirconium, alkaline earth metal, their alloys and compounds is used as an activator.

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