Bonding of Silicon Carbide Ceramics by using Active Brazing Metal (No.2)

Abstract

A bonding method in which the barrier layer was formed on the bonding surface of hot press sintered SiC ceramics (BeO or AlN as sintering additives) prior to active brazing metal (Ti-AgCu) was investigated in order to improve the bonding strength of SiC ceramics joints. In this report the material for the barrier layer and its effect were investigated.
The results of this study are as follows:
(1) The layer of reaction products between Cr powder and SiC ceramics as a barrier layer is effective to improve the bonding strength.
(2) The four point bending strength of the SiC joints by Ti-AgCu brazing metal with the Cr barrier laver of about 1.4μm in thickness on SiC was improved by the factor 3 to 5, as compared with the joints without Cr barrier layer. Then fracture position was in the SiC substrate. It is considered that Ag₂Si, Ti₅Si₄, etc. which were assumed to be the cause for low bonding strength in the previous report were not formed in the bonding layer.