抄録
As the metal-to-ceramic seal assemblies are usually used as part of a vacuum envelope, so the vacuum tightness seems to be important rather than the seal strength in the metal-to-ceramic seals. The brazing with Cu–Ag eutectic alloy was investigated from a viewpoint of vacuum tightness by means of the heat cycle test.
The results obtained are summarized as follows:
(1) Although the seal strength as brazed is scarcely influenced by brazing temperature, holding time and plating material, it is obvious from the results of the heat cycle test that the higher brazing temperature and the longer holding time give a better seal and Ni plating is superior to Cu plating.
(2) The vacuum tightness should be considered to be distinguished from the seal strength as they are independent essentially.
(3) Leak paths are usually formed not in the metallized region but in the brazed layer, especially along the plate-braze interface on either side of the Kovar or the metallized region.
