| Silicon nitride ceramics is a high temperature performance of the material,to achieve a reliable connection of silicon nitride ceramics has important practical value.In this paper,CuNiTi amorphous foil brazing filler metal with different content was successfully prepared by quenching method.The wettability of crystalline and amorphous CuNiTi on Si3N4 and the interfacial microstructure and the distribution of the elements in the brazing seam and the phase of Cu55Ni15Ti30 amorphous brazing solder Si3N4 were studied.The influence of brazing process parameters on the wettability of brazing filler and the effect of joint strength and the connection mechanism of ceramic brazing joint were analyzed.The deposition of Ti-Cu film on the quality of the joint was studied by depositing Ti film on Si.The effect of Ti-Cu film on the quality of the joint was studied.The effects of B,Pt,Mo and other elements to form a ternary composite transition layer.The influence of the composite transition layer on the performance of the brazed joint was studied.The influence of the infiltration of Mo into the interface and the influence of the interface was analyzed.(1)under the same brazing process conditions,amorphous brazing filler metal on the ceramic is better than the same composition of the crystalline brazing filler metal.The active elements of the amorphous brazing filler metal are more distributed at the interface when the crystalline and amorphous brazing materials are wetted.The activity of the active elements in the amorphous brazing filler metal is better than that of the crystalline brazing filler metal.Compared with the wetting angle at different wetting temperature and the spreading area under different holding time,the best brazing filler metal on Si3N4 is Cu50Ni15Ti35 amorphous brazing filler metal.(2)Cu55Ni15Ti30 brazing solder Si3N4 ceramics,brazing joint connection strength reached a maximum of 301.7 MPa;the best wetting performance Cu50Ni15Ti35 obtained the maximum joint connection strength of 284.3 MPa.Analysis of Cu50Ni15Ti35 amorphous brazing brazing Si3N4 ceramic joint composition: near the ceramic TiN reaction layer,the reaction layer and the filler between the TiN and Ti5Si3 composed of the connection layer,Cu composition of the main seam center area.TiNi,TiSi2,Ti5Si3,Ni3 Si,NiTiSi and CuTi are in the interface reaction layer.The concentration of Ti element is the highest at the interface between the interface reaction layer I and the interface reaction layer II,and the interface layer is hard TiN and silicified Staggered form.The NiTiSi phase composed of Ni,Ti and Si elements is aggregated in the central region of the brazing seam,and the main phase of Cu phase is distributed.(3)Ti and Ti-Cu metal films on Si3N4 surface can improve the wettability of brazing filler metal,but the TiN reaction layer formed on the ceramic surface hinders the further reaction between the brazing filler metal and the ceramic,but reduces the strength of the joint.Cu metal composite film on the joint strength is not much impact.B composite membrane infiltration can improve the oxidation resistance of the joints when brazing.Pd composite film can improve the high temperature strength of brazed joints.Si3N4 surface coating Mo composite film,the joints at room temperature bending strength is greatly improved;when the composite film Mo deposition 60 min,the joint strength of 374.9 MPa;solder alloy area Ni and Cu solid solution structure becomes uniform,small,The total thickness of the interface reaction layer was reduced to 2 ?m.Fracture occurred in the ceramic near the seam area,cut the surface smooth,no solder residue.Indicating that the solder on the ceramic to form an effective connection.It is shown that the infiltration of Mo element into the composite transition layer achieves the effect of strengthening the joint. |
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