| Title |
Effect of Additional elements in Ag - Cu Based Brazing Alloy on Bonding Strength and interfacial Structure of Si3N4 - 304 Stainless steel Joints (3) : Effect of In addition |
| Authors |
이우천(Woo Chun Lee); 강춘식(Choon Sik Kang) |
| Abstract |
Joining of 304 stainless steel to Si3N₄, ceramic using Cu-34.8%Ag-6.2%Ti brazing alloy was made in vacuum furnace. Effect of In addition in Cu-Ag-Ti alloy, brazing temperature, and brazing time on interfacial rections and bonding strength of Si₃N₄-STS304 joints were investigated. Bonding strenght was determined by fracture shear loading and high shear strength value of more than 195 MPa were obtained for joints brazed with Cu-Ag-Ti-1.4% In alloy at 1123 K for 1.2ks. The strong bonding is attributable to the formation of continuous Ti_5Si₄(/TiSi) layer with 0.2㎛ thick by redox reaction between Si₃N₄ and Ti at Si₃N₄ ceramic interface. The Ti_5Si₃(/Ti_5Si₄) was formed on the continuous Ti_5Si₄(/TiSi) layer and the FeTiSi on those layers was uniformly formed by solid-state reaction of Ti_5Si₃(/Ti_5Si₄) with Fe segregated/diffused from stainless steel. Thickness of interfacial reaction layer was increased and bonding strength was decreased as brazing temperature and brazing time were increased. Types of fracture observed at the strength test of Si₃N₄/STS304 joints was classified and schematic diagram of fracture mode with joint strength was proposed. |