Abstract
Pressureless sintered SiC ceramics joints and hot press sintered SiC ceramics joints were made by using active brazing metal (Ti-AgCu). Then the bonding strengths, the microstructures and reaction products of bonding layer were compared and discussed.
The results of this study are as follows:
(1) The four point bending strengths of pressureless sintered SiC ceramics joints were found to be equivalent to the bending strength of the SiC ceramics substrate (400 MPa). However, the four point bending strength of hot press sintered SiC ceramics joints were less than 100 MPa. Those strengths were extremely lower than that of the SiC ceramics substrate. Furthermore, the fracture position was at the interface between SiC ceramics and Ti-AgCu brazing metal.
(2) A TiC layer (0.2 pm thick) was observed in the bonding layer between pressureless sintered SiC ceramics and Ti-AgCu brazing metal. However, in the case of hot press sintered SiC ceramics, Ag2Si, Ti5Si4 and TiC were observed on the SiC side fractured surface. This was supposed to be the cause for the low bonding strengths of hot press sintered SiC ceramics joints.
