Study On Vacuum Brazing Technology And The Joint Strengthening Of Si₃N₄ Ceramics

In this thesis, using Cu-Ti brazing filler metal, Ag-Cu-Ti+TiN particulate composite solders, Ag-Cu-Ti+Ti/Al/Ti composite layer of Si2N4 ceramics connection Joints, the interfacial reaction factors and the impact of the joint properties.Cu-Ti brazing component design, and design of Cu-Ti brazing filler metal in the different process parameters and the connection between the Si3N4 ceramic. The results showed that:the Cu85Ti15 brazing temperature of 1180℃to connect, the Organization for 10min 5min brazing seam is more compact, uniform, brazing seam width is significantly wider, there is no obvious holes, porosity and other defects, solder cracks mainly by the major to form into about 5-6μm continuous interfacial reaction layer composed of Cu-Ti matrix and the intermetallic compounds CuTi2; the Cu80Ti20 solder and Cu85Til5 solder when compared to (1180℃, insulation 10min) brazing seam width increased, the interfacial reaction layer will not change much.The Ag-Cu-Ti brazing filler metal+TiN particulate composite solder brazing of Si3N4 ceramics with different processing parameters, the results show that:with the increase of the TiN particle volume fraction (5%,10%,15%), the weld width increase in particle size of TiN is more uniform, the joint strength is also gradually increased (15% to reach 141.6MPa), but enhanced particle TiN little effect on the reaction layer; with increasing holding time, the joint shear strength increased first and then decreased the joint strength in 20min relatively high (up to 126.4MPa), the holding time of 20min when the interfacial reaction layer thickness increases, the distribution of the solid solution is also more uniform, the shear strength of joints significantly improve the holding time increased to 30min, the interfacial reaction layer thickness is no longer, but the connector inside the solid solution is relatively reduced, allowing the joint to relieve residual stress, reduced ability to lead the joint shear intensity decreases.This article also examined the Ag-Cu-Ti brazing filler metal+Ti/Al/Ti composite layer generated by the in situ reaction of intermetallic compounds, the connection of the Si3N4 ceramic analysis showed that:Al foil and Ti foil thickness, AgCuTi initial thickness holding time, as well as the intermediate layer surface treatment status and other factors have some impact on the joint of; by step heating and two-step heating contrast that, the two-step heating is more conducive to refine the intermetallic compound particles, due to lower interfacial reactions layer thickness, and therefore more conducive to the performance of the joints; put some pressure on the joint strength but decreased when Ti foil and Al foil thickness in the joints; in the Ti foil with Al foil thickness is small, with or without pressure little effect on joint strength.