EFFECT OF Ti CONTENT ON THE MICROSTRUCTURE AND PROPERTIES OF Si_3n_4/Si_3N_4 JOINT BRAZED USING Cu-Zn-Ti ALLOY

St3N4 ceramic was brazed using a filler of Cu - Zn - Ti alloy under the brazing condition of 1223K and 1.8ks. When the Ti content in the alloy is 20% at., the average shear strength of the joint is 265MPa. By using EPMA and XRD analysis, the metallurgical behavior of the interface between the filler alloy and Si3N4 matrix was studied,which affected the joint strength.It was found that with in- creasing Ti content from 5% to 20%at., the thickness of the brazing seam decreases and the amount of the reactant(Ti5Si3, TiN and Ti2N etc. ) increases,resulting in an obvious increase of the shear strength of the joint.