Joining of Si{sub}3N{sub}4 using rapidly-solidified CuNiTiB brazing filler foils

摘要

Joining of Si{sub}3N{sub}4 to Si{sub}3N{sub}4 was performed using newly developed rapidly-solidified CuNiTiB brazing foils of different thickness, three-point bending tests then being employedat room temperature to measure the strength of the joints. The microstructures of the joints wereobserved and the element area distribution of Cu, Ni and Ti was examined by scanning electronmicroscope with an X-ray wave-dispersion spectrometer. The results of the strength test show thatwhen using rapidly-solidified brazing filler foils of suitable thickness (for example, 40μm and 80 μm) the joint strength was increased greatly (up to 402 MPa and 380 MPa respectively) compared withthe use of paste brazing filler of the same alloy. Moreover, the fracture form of theSi{sub}3N{sub}4/Si{sub}3N{sub}4 joints also varied with the change of strength. The thickness ofthe brazing foils used has an important effect on the corresponding joint strength, reasons for whichare discussed.