Liquid-film assisted formation of alumina/niobium interfaces
Alumina has been joined at 1400 degrees C using niobium-based interlayers. Two different joining approaches were compared: solid-state diffusion bonding using a niobium foil as an interlayer, and liquid-film assisted bonding using a multilayer copper/niobium/copper interlayer. In both cases, a 127-(mu)m thick niobium foil was used; =1.4-(mu)m or =3-(mu)m thick copper films flanked the niobium. Room-temperature four-point bend tests showed that the introduction of a copper film had a significant beneficial effect on the average strength and the strength distribution. Experiments using sapphire substrates indicated that during bonding the initially continuous copper film evolved into isolated copper-rich droplets/particles at the sapphire/interlayer interface, and extensive regions of direct bonding between sapphire and niobium. Film breakup appeared to initiate at either niobium grain boundary ridges, or at asperities or irregularities on the niobium surface that caused localized contact with the sapphire.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director, Office of Science. Office of Basic Energy Studies. Materials Science and Engineering Division (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 806100
- Report Number(s):
- LBNL-48606; JACTAW; R&D Project: 512703; B& R KC0201030; TRN: US200303%%533
- Journal Information:
- Journal of the American Ceramic Society, Vol. 85, Issue 10; Other Information: Journal Publication Date: Oct. 2002; PBD: 16 Jun 2002; ISSN 0002-7820
- Country of Publication:
- United States
- Language:
- English
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