Abstract
Electrical Sialon ceramics having TiN were joined with SKS3 metal by using a Ag-Cu-Ti active brazing metal layer having a thickness of 100 μm or 400 μm at 1113 K for 300 s in a vacuum. Residual stress distribution in the ceramics and metal sides was measured by X-ray stress analysis. High residual stress over several hundred MPa was detected in a region up to about 10 mm from the brazed interface in the metal side of brazed joint sample. To reduce the residual stress by plastic deformation of the brazing metal layer, stress relaxation methods such as heat treatment after joining and use of insert metal were applied. These methods were effective to relax the residual stress of σy in the ceramics side (σy : residual stress in vertical direction to the brazed interface). Four-point bending strength of the brazed joint specimen was well related to the peak value of σy in the ceramic side and the average value of σx in the metal side of the brazed joint sample (σx : residual stress in parallel direction to the brazed interface). In the case of high strength brazed joint specimen, the four-point bending strength showed 85 % of the strength of Electrical Sialon at room temperature. The strength decreased with increasing the temperature.
