| abstract |
Cylindrical tubes made of translucent aluminum oxide ceramic (1), which have metal current feedthroughs (2) at the ends, are sealed in a vacuum-tight manner. To do this, apply a metallizing paste to the ends of the tube a) at least one finely divided metal powder made of tungsten, molybdenum, niobium or tantalum, b) a liquid organic binder and c) contains a powdered calcium-magnesium silicate with a melting point in the range from 1200 to 1500 ° C, burns the paste on the alumina ceramic and thus creates a thin metal layer, chemically or galvanically deposits another layer of nickel or copper on the remaining metal layer, inserts metal current feedthroughs in the pipe in the area of the pipe ends and closes it Ends with the aid of a hard solder (5) with a melting point between 950 and 1 200 ° C, z. B. a Cu / Ag alloy, optionally using disc-shaped sealing elements (4) at the metallized points. |