Active Alloy Brazing Al₂O₃ Ceraics And Metal

In active brazing of ceramics and metal with active element contained in the brazing filler materials, there will be reaction layer formed in the reaction of the element and the ceramics. The active alloy brazing method causes more attention for its good welding quality, high joint reliability, and high welding efficiency, especially working under some condition of high temperature, high stress and erosion. Now the method is widely used in electricity vacuum switching valve, spacecraft, weaponry, automobile and energy.In this thesis, the influence of the component of the active brazing filler materials and brazing process parameters on the joint properties has been studied. The reaction product and connecting mechanism of ceramics-metal are analysed with SEM and XRD technology.Brazing Al₂O₃ ceramics and non-oxygen copper with Ag₇₂Cu₂₈ brazing filler materials added element Ti, we can get high quality brazed joints, and the highest sealing strength can be up to 103 Mpa. And the sealing strength rises with the Ti% rising when Ti% under 3wt%, and when Ti% above 3wt%, the strength reduces with Ti% rising. The strength gets the highest when Ti% is 3wt%. The metallurgical bonding can be realized , but the strength didn't rise when using Al₂O₃ and SiC-particulate-contained composite (Ag₇₂Cu₂₈)₉₇Ti₃ filler brazing materials.After active alloy brazing Al₂O₃ ceramics and non-oxygen copper with (Ag₇₂Cu₂₈)₉₇Ti₃ in different temperatures and pulling different pressure, the proper brazing process parameters can be determined: brazing temperature: 850℃, non-pressure, holding time: 5 min.The active element Ti can react with Al₂O₃ ceramics and form reaction layer which can join ceramics and metal. The active brazing mechanism studied in this thesis is that the active element Ti formed...