Research On Process Of Brazing Copper To Alumina Ceramics Using Reactive Alloys

The effective connection between alumina ceramics and metal can not only exert the unique and excellent performance of alumina ceramic and metal,but also can make up the defect of themselves performance.Pure copper,as the electrical and thermal conductivity rate second only to silver,relatively inexpensive and readily available material,is widely used in electrical and thermal conductivity of devices and equipment.The excellent performance of composite component of alumina ceramic and copper is of extraordinary significance to promote the progress of energy,power electronics,aerospace and other important areas.In this paper,the Ag-Cu-Ti active filler metal was prepared by the Ag-Cu eutectic powder and TiH2 powder as raw materials.The influence of the change of active element Ti in Ag-Cu-Ti active filler metal on the wetting of the alumina ceramic was explored.The brazing joint is filled with two kinds of powders uniformly mixed,and then,start to carry out active brazing of alumina ceramic and copper.Adjusting the weight content of TiH2 powder to 5wt%,10wt%and 15wt%,explore the effect of the content of active element Ti on microstructure and properties of brazing joint.Accordingly,this subject creatively put forward a new solder filling method.Firstly,spray Ag-Cu eutectic powders to the welding surface of copper.Secondly,fill the TiH2 powders between the surface of alumina ceramic and the surface of copper with Ag-Cu eutectic sprayed.Thirdly,braze copper to alumina ceramics with this filling method.Influence of Ti content on microstructure and properties of brazing joint were observed and analyzed.Get the following conclusion:using the new solder filling method,the thickness of the reaction layer is wider and more uniform after welding.And,when the content of Ti is 2wt%and 3wt%,the brazing temperature is 875 ℃,holding time is 60 min,vacuum brazing degree is 3.0×10-2Pa,no extra pressure on specimens in brazing process,reliable connection can be abtained between alumina ceramic and copper.Detection methods such as EDS and XRD experiment,and thermodynamic analysis method have been used to explore into the interface reaction process and the bonding mechanism.After analysis,achieving a metallurgical bonding joint between alumina ceramic and pure copper was confirmed.And the products,such as AlTi and AlxTiy,play an excellent role in the transition of the two kinds of materials.