JOINING OF ZIRCONIA CERAMIC TO STAINLESS-STEEL AND TO ITSELF USING AG57CU38TI5 FILLER METAL

The brazing of ZrO2 ceramic to 1Cr18Ni9Ti stainless steel and to itself was performed using Ag57Cu38Ti5 filler metal under a vacuum of 7 x 10(-3) Pa. The effects of interlayer copper on the ceramic to stainless steel joint strength, and the brazing temperature (1073 to 1323 K) and holding time (0 to 60 min) on ceramic to ceramic joint strength were investigated. The joint strength was evaluated by shear testing. An interfacial reaction layer between the ceramic and the filler metal was found, and the reaction products were delta-TiO and gamma-AgTi3. The joint strength of ZrO2 ceramic to stainless steel was improved by using a layer of copper of a suitable thickness. The brazing temperature and holding time had a strong influence on the joint strength of ceramic to ceramic, and the joint strength was mainly controlled by reaction layer thickness and the properties of the reaction products. The maximum shear strength was obtained for brazing at 1123 K for 30 min and an interfacial reaction layer thickness of similar to 4.4 mu m.