Hoechst Ceramtec Aktiengesellschaft

Tha Do-Thoi

Peter Stingl

Klaus Popp

Gerd Meier

Volker Dietrich

The invention relates to a composite body in which a ceramic component and a metal component are bonded to one another by internal soldering. The internal soldering is effected with soldering composition in a recess (2) within a component (1) of the one material in which there is arranged a component (3) of the other material which is shaped to fit accurately. The recess (2) is, at at least one end-face opening, surrounded by a chamfer (5) having an angle .phi. smaller than 35.degree. C., while the wetting angle .beta. between the soldering composition and the plane of the component surface in which the recess is located is smaller than 40.degree..

Internal soldering in metal/ceramic composites

A process is described for electrolessly depositing or electrodepositing a solder layer composed of copper and silver and having an overall composition of silver/copper of from 75:25 to 70:30 and a total layer thickness of 15 to 100 .mu.m on a metallized ceramic. In this process, copper layers and silver layers are deposited alternately on the metallized ceramic. The number of layers is at least 3 and the individual layer thickness is 5 to 10 .mu.m.

Metal-ceramic joint

A surge voltage protector having a tubular ceramic part as an insulator, and having metal electrodes soldered onto the end faces thereof. Each electrode is electrically connected in each case to an ignition aid applied at least to the inside wall of the ceramic part. The inside edges of the surfaces joining the ceramic part to the electrodes are each provided with a chamfer whose chamfer angle is 15.degree. to 60.degree. relative to the plane of the joining surfaces. The width projected onto the plane of the joining surface is 0.05 to 0.4 mm.

Surge voltage protector

A solder coating is applied to a metallized ceramic part in that at least two layers, in each case composed of nickel, copper, silver, zinc or tin, are applied chemically or galvanically. Under the soldering conditions molten solder metal forms on these layers. Useful layers for hard solders are those which are in each case composed of Ni, Cu or Ag. For example, a layer of nickel, copper or silver, with a layer thickness of at least 0.5 .mu.m, can be first applied to the metallized ceramic part, followed by at least one further layer of nickel, copper or silver with a layer thickness of 10-105 .mu.m, until a total layer thickness of 15-300 .mu.m is obtained.

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Rothenbach, Germany

Tha Do-Thoi