Microstructural Behavior during Bonding of Alumina to Niobium by Liquid State Diffusion

Abstract:

The objective of this work was to study various aspects of liquid state diffusion bonding of cylindrical samples of Al₂O₃ and commercially pure niobium (99.7%) by brazing using a 25 µm thick 70Cu-30Zn (wt%) alloy as joining element. Initially, sintering of alumina powder was carried out in order to produce a 7 mm diameter samples at 1550°C by 120 minutes. Joining experiments were carried out on Al₂O₃/Cu-Zn/Nb/Cu-Zn/Al₂O₃ sandwich-like combinations at temperature of 920°C, 950°C and 980°C using different holding times under argon (Ar) atmosphere. The experimental results show a successful joining of alumina to niobium at 950°C and 980°C, however not at 920°C. Joining of Al₂O₃/Cu-Zn/Nb/Cu-Zn/Al₂O₃ occurred by the formation of a homogeneous diffusion zone with no interfacial cracking or porosity at the interface. Scanning electron microscopy (SEM) micrographs show the layer formed in the reaction zone. It was observed that the width of the reaction zone increases with bonding temperature and time. Electron probe microanalysis (EPMA) revealed that at any particular bonding temperature, Nb travel into the Cu-Zn joining element forming a circular precipitate phase near to the alumina ceramic.

• Periodical: Materials Science Forum (Volume 755)
• Pages: 171-177
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.755.171
• Online since: April 2013
• Authors: Julieta Alonso-Santos, Mercedes G. Téllez-Arias, Egberto Bedolla, José Lemus-Ruiz
• Keywords: Alumina, Diffusion Bonding, Interface Characterization, Metal-Ceramic Brazing, Niobium

References

[1] N. Bahlawane and T. Watanabe, New sol–gel route for the preparation of pure α-alumina at 950°C, J. Am. Ceram. Soc. 83 (2000) 2324-2326.

DOI: 10.1111/j.1151-2916.2000.tb01556.x

[2] T. Ebadzadehw and L. Sharifi, Synthesis of ι-Al2O3 from a mixture of aluminum nitrate and carboxymethyl cellulose, J. Am. Ceram. Soc. 91 (2008) 3408-3409.

[3] R. Asthana and M. Singh, Evaluation of Pd-based brazes to join silicon nitride to copper-clad-molybdenum, Ceram. Intern. 35 (2009) 3511-3515.

DOI: 10.1016/j.ceramint.2009.05.011

[4] P. He, J.C. Feng and W. Xu, Microstructure and kinetics of induction brazing TiAl-based intermetallics to steel 35CrMo using AgCuTi filler metal, Mater. Sci. Eng. A 418 (2006) 53-60.

DOI: 10.1016/j.msea.2005.11.003

[5] A.M. Saeed, Z. Hussain, A. Badri and T. Ariga, The effects of welding parameters on the weldability of different materials using brazing alloy fillers, Mater. Design 31 (2010) 3339-3345.

DOI: 10.1016/j.matdes.2010.01.059

[6] C.F. Liu, J. Zhang, Y. Zhou, H.L. Yi and M. Naka, Effect of holding time on the self-joining of silicon nitride, J. Alloys Compd. 471 (2009) 217-221.

DOI: 10.1016/j.jallcom.2008.03.059

[7] H. Firmanto, P. Hussain and O. Mamat, Reaction layers of the diffusion-bonded sialon and high-chromium steel, J. Appl. Sci. 11 (2011) 1809-1814.

DOI: 10.3923/jas.2011.1809.1814

[8] Y.M. He, J. Zhang, C.F. Liu and Y. Sun, Microstructure and mechanical properties of Si3N4/Si3N4 joint brazed with Ag–Cu–Ti + SiCp composite filler, Mater. Sci. Eng. A 527 (2010) 2819-2825.

DOI: 10.1016/j.msea.2010.01.065

[9] R.K. Roy, A.K. Panda, S.K. Das, Govind, A. Mitra, Development of a copper-based filler alloy for brazing stainless steels, Mater. Sci. Eng. A 523 (2009) 312-315.

DOI: 10.1016/j.msea.2009.05.049

[10] M.M. Schwartz: Ceramics Joining (American Society for Metal, Metal Park, USA(1990).

[11] B. Lesage, Some aspects of diffusion in ceramics, J. Physique III 4 (1994) 1833-1850.

[12] J. Lemus and R.A.L. Drew, Joining of silicon nitride with a titanium foil interlayer, Mater. Sci. Eng. A 352 (2003) 169-178.

DOI: 10.1016/s0921-5093(02)00892-4