SU100646A1 - Method for blackening metal parts of vacuum and gas discharge devices - Google Patents

Description

In vacuum and gas discharge devices there are metascal details that must have a high coefficient of thermal radiation. To do this, they blacken parts or the metal from which the parts are made by treating them at high temperatures in hydrocarbon vapors.

This method of blackening metal is associated with the need to use volatile and harmful substances. The surface of the parts blackened by this method is covered with carbon, which often contains undesirable impurities for vacuum parts, as a result of which the gas separation time is extended.

The blackened parts obtained in this way do not withstand overheating by more than 700 °, which does not always satisfy the requirements of their further processing.

In order to increase the temperature resistance of the coating applied to the metal part and simultaneously with blackening the cleaning of the surface of the part and its outgassing, it is proposed to treat the parts in a gas discharge with a constant or alternating current under conditions of cathode sputtering of the metal with ions and subsequent deposition of the sprayed particles

the surface of the part, as used as a cathode, at a direct current, or any of the electrodes at an alternating current.

With appropriate gas discharge parameters (gas or vapor pressure, discharge current density, voltage) for a certain gas or vapor, conditions can be created when the surface of the cathode (at constant current) and the surface of both electrodes (at alternating current) become covered with dark by layer. This dark layer on the metal is formed as a result of two processes - cathode sputtering of the electrode material under the ion shells and the subsequent deposition of sputtered particles on the surface of the part.

The discharge parameters are selected so that the number of returning sputtered particles is sufficient to cover the part with black bloom. The blackening time in the discharge depends on the pressure of the gas or vapor, the density of the discharge current, the type of gas or vapor, and the type of metal.

By varying the blackening time in the discharge, the type of gas and the discharge parameters, a black layer of different density and thickness can be obtained on the metal surface.

In the process of blackening in the gas discharge, the metal or parts of the electric vacuum and gas discharge lamps are simultaneously subjected to surface cleaning and degassing.

At the initial impact of the discharge onto the metal surface, all impurities and oxides are removed from it, and then the surface itself begins to be treated. In the gas discharge, as a result of ion bombardment of significant speeds, parts are degassing. In this case, the gas contaminating the metal is removed not only from the surface of the latter (this is achieved by simple heating), but also from the deep layers due to the penetration of gas ions into the thickness of the metal and knocking out the gas contaminating the metal.

Subject invention

The method of blackening metal parts of vacuum and gas-discharging devices by forming a coating layer on the surface of a part, characterized in that, in order to increase the temperature resistance of the coating and onset, simultaneously with the blackening of the surface of the part and its outgassing, the parts are treated in a gas discharge an alternating current under the conditions of a cathode distribution of metal by the impact of ions and the subsequent deposition of sputtered particles on the surface of a part that is isotope as a cathode - at a constant Oka, or any of the electrodes - with alternating current.