SU1163755A1 - Current conducting paste for manufacturing cathodes of gas discharged instrume ments - Google Patents

Abstract

ACCELERATING PASTE FOR THE MANUFACTURE OF CATALODS OF GAS-DISCHARGE DEVICES, containing a non-precious metal boride, powder of low-melting glass and an organic binder, differs from the fact that, in order to reduce the ignition voltage and increase the durability of the device, the paste additionally contains a low-allergic powder, an oxide powder and an amount of an amount of an amount of an amount of an amount of an oxide powder , A1, Md, Ba with the following content of components, wt.%: Non-precious metal boride 60-80 Fusible glass powder with melting point not higher than 700 ° C 3-10 Finely dispersed. powder of metal oxide from the group Be ;, Ba, At, Mg1-6 Organic binder with burnout temperature not higher than 500 ° C;

Description

The invention relates to the field of electronic equipment and may find application in the manufacture of gas discharge devices (HF). for example, for the manufacture of cathodes of gas-discharge direct-current indicator panels, zener diodes, etc.

The aim of the invention is to reduce the ignition voltage and increase the durability of hydraulic fracturing by improving the emission properties of the cathodes and their small atomization in the discharge.

The injection of fine powder of a light metal oxide into the paste causes high emission properties of the cathode, a small sputtering coefficient and a constant cathode potential drop.

When the content in the paste of a light metal oxide is less than 1%, a high ignition voltage is observed and the durability of hydraulic fracturing is low.

If more than 6% of a light metal oxide is present in the paste, the conductive properties of the paste deteriorate, since dramatically increases the resistance of the electrodes.

About Sl)

The particle size of the oxide of the light metal did not exceed 20 microns, since larger size

The oxide particles lead to a contraction of the discharge of the SL p and on them and, as a result, to an unstable operation of the device. In addition, the particle size

the light metal oxide affects the printing properties of the paste.

The following glass grades were tested for use in the paste:

C48-2, containing, wt%; SiOa 65-68, B203 20-23, A1203 3-4, NaaO 2.2-3.8. Kao 4.1-6.2;

C82-3, containing, wt.%; PvO 66-76, VaOz 13-18, SiQ2 8-15, A) 20z 1.4-2.5;

(PP1. containing, wt.%; PbO 27-35, (vjCX 17 23. ZnO 34-38. 51026-10, PjOs 1.5, 5.

As a low-melting glass, low-melting crystallizable glass and a mixture of low-melting and low-melting crystallized glass can be used.

When choosing an organic binder, the outcome is as follows:

inertness to metals and their oxides

good wettability of the glass substrate of the powders;

full burnout at a temperature not higher than 500 ° С:

the dependence of the viscosity of the paste on temperature is small,.

Based on literature data, many organic binders satisfy these requirements. The following organic binders were tested for use in the paste:

60% lanolin plus 40% ethylcellulose solution in terpineol;

3-8% solution of ethylcellulose in terpineol ,.

Example 1 Electrodes were made from a conductive paste containing, in May,%, on a glass substrate using screen printing;

Powder poluboride nickel 75

Powder fusible

C48-25 glasses

Fine powder of the lung oxide

metal (BeO) with size

particles 0.1-5 μm4

Organic binder

(3% ethylcellulose solution in terpineol) 16

Then, the diode structure of the device was assembled, sealed, pumped out, filled with Ne + 1% Ar to a pressure of LLP, mm Hg, and the device was trained. After that, the ignition voltage of the gaseous discharge wave was measured at 180 V. The durability at a current density of 50 mA /: m in a static mode was 620 h.

Example 2 Electrodes were made from a conductive paste containing, in wt%, on a glass substrate using a screen printing method;

Poluboride Powder

cobalt 70

Powder fusible

glass SB517

Fine powder

light metal oxide A120z with

particle size 0.5-10 microns 1

Organic binder (8% solution of cellulose cellulose in terpineol) 22

But all the technological operations were carried out in accordance with Example 1. The gas discharge ignition voltage was 185 V, the durability was 610 hours.

Example 3 Technologists are similar to examples 1 and 2, but another paste composition was taken, 0 wt.%:

Cobalt boride powder76

Powder fusible glass C82-33

Fine powder 5 of light metal oxide MDO with

particle size 0.5-2 µm 6 Organic binder (60% lanolin and 40% 2% aqueous solution of ethylcellulose in terpineol) 15

Ignition voltage 191 V, durability 600 hours.

The limiting values of the compositions are given in Table 1.

5The conductive paste for the manufacture of cathodes for hydraulic fracturing (hfe 1-7) contains non-precious metal boride (NlaB) and low-melting glass powders, a fine powder of light metal oxide (BeO) with a particle size of 0.1-5 microns and an organic binder (ethylcellulose solution in terpineol), wt.%: Paste 1

Nickel boride 63 powder

5Fusible powder

C48-210 glass

Fine powder of beryllium oxide 1

8% ethylcell solution in terpineole26

Pasta 2

Nickel boride 77 powder

C48-23 Fusible Glass Powder

5Fine powder

beryllium oxide 3.5.

3% ethylcellulose solution in terpineole14 Paste 3

0 Nickel boride 72 powder

Powder fusible glass C48-25.5

Fine powder of beryllium oxide 3,5

5 5% solution of ethylcellulose in terpineole19 Paste 4

Nickel boride boride 66 powder

Powder fusible glass C48-27

Fine powder

beryllium oxides

5% ethylcellulose solution in terpineol

Pasta 5

Nickel boride powder

Fusible Powder

C48-2 glasses

Fine powder

beryllium oxides

5% ethylcellulose solution in terpineol

Pasta b

Nickel boride powder

Fusible Powder

C48-2 glasses

Fine powder

beryllium oxides

5% ethylcellulose solution in terpineol

Pasta 7

Nickel boride powder

. Powder fusible

C48-2 glasses

Fine powder

beryllium oxides

5% solution of ethylcellulose in terpinole21

Note Conductive pastes with a content of the main functional material of less than 60% and more than 80% to produce in production is not possible.

The use of low-melting glass in the paste over 10 wt.% Leads to an increase in the resistance of the cathodes (paste 7), and below 3 wt.% Reduces the adhesion to the substrate (paste 6),

Beryllium oxide compositions limit values - pastes 4 and 5,

The use of pastes 4 is not possible due to the very high resistance of the cathodes.

The use of paste 5 is impractical due to the increased ignition voltage of the gas discharge and low durability,

Table 2 shows examples of the specific implementation of pastes based on cobalt boride and an assessment of their properties from the point of view of ignition voltage and durability.

Compounds of 8 and 10 give good results from pasta based on borg1d cobalt,

Table 1

table 2

Claims (1)

CONDUCTIVE PASTE FOR MANUFACTURING CATHODES OF DISCHARGE INSTRUMENTS, containing base metal boride, low-melting glass powder and an organic binder, characterized in that in order to reduce the ignition voltage and increase the durability of the device, the paste additionally contains a finely dispersed metal oxide group Be, Al, Mg, Ba with the following content of components, wt.%: Base metal boride 60-80 Powder of low-melting glass with a melting point not higher than 700 ° С3-10 Fine powder of metal oxide from the group Be, Ba, Al, Md1-6 Organic binder with a burn-out temperature not higher than 500 ° С