Investigation of brazing of Ba(Zn0.33Ta0.67)O3 ceramic with Ti6Al4V alloy

Feasibility of brazing Barium Zinc Tantalate (BZT) ceramics with Ti6Al4V alloy using active and non-active brazing alloy was investigated in the present study for high power RF window application. BZT ceramics were brazed successfully with Ti6Al4V alloy under high vacuum with active brazing alloy (Ticusil® (4.5%Ti) and Cusil-ABA® (1.5%Ti) at 850 °C and non-active brazing alloy (BAg8) at 830 °C. Micrographs at the interface of non-active brazed joints are free of interfacial micro-defects, and exhibit excellent physical contact and good metallurgical bonding with high diffusivity when compared to active-brazed joints. Ceramic-filler interfacial layer thickness is high for samples containing non-active filler (~25 µm) compared to the samples containing active filler materials (~9 µm and ~5 µm). The average shear strength of BZT ceramics brazed with non-active brazing alloy BAg8 is higher (~45.5 MPa) in comparison with active brazing alloys (~33 MPa and ~31 MPa). Fracture surface reveals that the failure is on ceramics side only indicating that the strength of non-active brazed joint is more compared to ceramics.