Hostname: page-component-586b7cd67f-dsjbd Total loading time: 0 Render date: 2024-11-22T21:14:46.070Z Has data issue: false hasContentIssue false
  • English
  • Français

High-temperature tolerance of the silver-copper oxide braze in reducing and oxidizing atmospheres

Published online by Cambridge University Press:  01 June 2006

J.Y. Kim ,
J.S. Hardy  and
K.S. Weil
J.Y. Kim*
Affiliation:
Pacific Northwest National Laboratory, Richland, Washington 99352
J.S. Hardy
Affiliation:
Pacific Northwest National Laboratory, Richland, Washington 99352
K.S. Weil
Affiliation:
Pacific Northwest National Laboratory, Richland, Washington 99352
*
a) Address all correspondence to this author.e-mail: [email protected]
Get access

Abstract

The silver-copper oxide–based reactive air brazing technique was developed as a method of joining complex-shaped ceramic parts. To investigate the viability of this approach for high-temperature application, a series of air-brazed alumina joints were independently exposed to either oxidizing or reducing atmosphere at 800 °C for 100 h. Those samples that were thermally aged in air maintained good joint strength, similar to that of the original as-brazed samples. Microstructural analysis revealed no significant change in joint microstructure after long-term oxidation at elevated temperature, indicating excellent stability of the Ag–CuO-based filler metal in this environment. On the other hand, exposure of the air-brazed alumina joints to hydrogen under the same aging conditions resulted in a measurable decrease in joint strength. Scanning electron microscope analysis conducted on the fracture surfaces of the broken hydrogen-exposed specimens indicated that the source of joint failure was debonding along the interface between the filler metal and alumina substrate. This was due in large part to internal reduction of CuO precipitates within the filler metal to copper and accompanied by the simultaneous formation of porosity at these sites, both within the bulk of the joint as well as along the filler metal/substrate interfaces. Pore formation was noticeably present in filler metals prepared with a high concentration of copper oxide.

Keywords

BrazingMicrostructureStrength
Type
Articles
Information
Journal of Materials Research , Volume 21 , Issue 6 , June 2006 , pp. 1434 - 1442
Copyright
Copyright © Materials Research Society 2006

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1.Eichler, K., Solow, G., Otschik, P., and Schaffrath, W.: Degradation effects at sealing glasses for the SOFC, in Proc. 4th Eur. Solid Oxide Fuel Cell Forum edited by McEvoy, A.J. (European Fuel Cell Forum, Oberrohrdorf, Switzerland, 2000), pp. 899–906.Google Scholar
2.Singh, M., Shibayama, T., Hinoki, T., Ando, M., Katoh, Y., Kohyama, A.: Joining of silicon carbide composites for fusion energy applications. J. Nucl. Mater. 283–287B, 1258 (2000).Google Scholar
3.Pippel, E., Woltersdorf, J., Colombo, P., Donato, A.: Structure and composition of interlayers in joints between SiC bodies. J. Eur. Ceram. Soc. 17, 1259 (1997).CrossRefGoogle Scholar
4.Kim, J-H., Yoo, Y-C.: Bonding of alumina to metals with Ag–Cu–Zr brazing alloy. J. Mater. Sci. Lett. 16, 1212 (1997).CrossRefGoogle Scholar
5.Powers, M.: Active metal brazing for ceramic-to-metal joining, in Proceedings 1997 International Systems Packaging Symposium (Int. Microelecton. & Packaging Soc., Reston, VA, 1997), p. 124.Google Scholar
6.Arroyave, R., Eagar, T.W.: Metal substrate effects on the thermochemistry of active brazing interfaces. Acta Mater. 51, 4871 (2003).Google Scholar
7.Zhu, M., Chung, D.D.L.: Active brazing alloy containing carbon fibers for metal-ceramic joining. J. Am. Ceram. Soc. 77, 2712 (1994).CrossRefGoogle Scholar
8.Kim, J.Y., Hardy, J.S., Weil, K.S.: Effects of CuO content on the wetting behavior and mechanical properties of a Ag–CuO braze for ceramic joining. J. Am. Ceram. Soc. 88, 2521 (2005).Google Scholar
9.Hardy, J.S., Kim, J.Y., Weil, K.S.: Joining mixed conducting oxides using an air-fired electrically conductive braze. J. Electrochem. Soc. 151, J43 (2004).CrossRefGoogle Scholar
10.Kim, J.Y., Hardy, J.S., Weil, K.S.: Silver-copper oxide based reactive air braze (RAB) for joining yttria-stabilized zirconia. J. Mater. Res. 20, 636 (2005).CrossRefGoogle Scholar
11.Weil, K.S., Kim, J.Y., Hardy, J.S.: Reactive air brazing: A novel method of sealing SOFCs and other solid-state electrochemical devices. Electrochem. Solid-State Lett. 8, A133 (2005).CrossRefGoogle Scholar
12.Kim, J.Y., Hardy, J.S., Weil, K.S.: Use of aluminum in air-brazing aluminum oxide. J. Mater. Res. 19, 1717 (2004).CrossRefGoogle Scholar
13.Meier, A.M., Chidambaram, P.R., Edwards, G.R.: A comparison of the wettability of copper-copper oxide and silver-copper oxide on polycrystalline alumina. J. Mater. Sci. 30, 4781 (1995).CrossRefGoogle Scholar
14.Shüler, C.C., Stuck, A., Beck, N., Keser, H., Täck, U.: Direct silver bonding—An alternative for substrates in power semiconductor packaging. J. Mater. Sci. Mater.-Electron. 11, 389 (2000).CrossRefGoogle Scholar
15.Klueh, R.L., Mullins, W.W.: Some observations on hydrogen embrittlement of silver. Trans. Metall. Soc. AIME 242, 237 (1968).Google Scholar
16.Singh, P., Yang, Z.G., Viswanathan, V., Stevenson, J.W.: Observations on the structural degradation of silver during simultaneous exposure to oxidizing and reducing environments. J. Mater. Eng. Perform. 13, 287 (2004).CrossRefGoogle Scholar
17.Shao, Z.B., Liu, K.R., Liu, L.Q., Liu, H.K., Dou, S.: Equilibrium phase diagrams in the systems PbO–Ag and CuO–Ag. J. Am. Ceram. Soc. 76, 2663 (1993).Google Scholar
18.Darsell, J.T., Weil, K.S.: The effect of Pd additions on the invariant reactions in the Ag–CuO x system. J. Phase Equil. Diff. 27, 92 (2006).CrossRefGoogle Scholar
19.Yoshino, Y., Shibata, T.: Structure and bond strength of a copper–alumina interface. J. Am. Ceram. Soc. 75, 2756 (1992).Google Scholar
20.Chatain, D., Chabert, F., Ghetta, V., Fouletier, J.: New experimental setup for wettability characterization under monitored oxygen activity: II, wettability of sapphire by silver-oxygen melts. J. Am. Ceram. Soc. 77, 197 (1994).CrossRefGoogle Scholar
21.Massalski, T.B., Okamoto, H., Subramanian, P.R., Kacprzak, L.: Binary Alloy Phase Diagrams 2nd ed. (ASM International, Materials Park, OH, 1990), Vol. 1, p. 66.Google Scholar