1990 Fiscal Year Final Research Report Summary
Heat-Resistant Brazing of Ceramics to Metals
| Project/Area Number |
63470054
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
溶接工学
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| Research Institution | Osaka University |
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Principal Investigator |
NAKA Masaaki Osaka University Welding Research Institute Associate Professor, 溶接工学研究所, 助教授 (00005985)
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| Co-Investigator(Kenkyū-buntansha) |
OKAMOTO Ikuo Osaka University Welding Research Institute Professor (90029009)
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| Project Period (FY) |
1988 – 1990
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| Keywords | Joining / brazing / ceramics / metal / titanium / coating / nickel / silicon carbide |
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| Research Abstract |
Joining of ceramics to metals necessitates the superior wetting of molten filler metals against ceramics, and also the high heat-resistance of the metals.
The present work investigates (1) the improvement of wetting of metals against ceramics by pre-coating Ti film on the ceramics and (2) developement of the nickel filler metals with the high melting points. The results obtained as follows,
I) The pre-coating of Ti on silicon carbide improves effectively the wetting of molten copper. Ti in molten Cu-Ti alloys reacts with SiC and forms TiC and Ti_5Si_3. The formation of compounds is attributable to the improvement of wetting of Cu.
Although the strength of Cu/SiC interface is improved by increasing the thickness of pre-coating Ti, the strength of interface is decreased at the thickness of Ti above 9.2 mum. The proper thickness of Ti provides the maximum strength of Cu/SiC interface.
(II) The usage of Ni-Ti filler metals with higher melting points, compared with that of Ag-Cu filler metals is applied to join ceramics to metals, and the joining interface is investigated by observing microstructures and interface strength. The increase in Ti content of the filler reduces the thickness of the joining layer and amounts of defects in the layer. The reaction of Ti in the filler with SiC results in the formation of TiC. The free graphite except TiC is formed by reacting Ni with SiC at the Ti content of 30 at% or below in the Ni-Ti filler. The formation of free graphite is Supperesed at Ti content of 30 at% or more in the filler. This accounts for the improvement of strength of SiC/SiC joint with Ni-Ti filer metals. The joining of SiC to W can be joined with Nb interlayer using Ni-50Ti filler. The formation of titanium carbide of (Ti, Nb) C, and other several inter-metallic cmpounds to the filer metal/SiC interface are attributable to the high heat-resistance of SiC/metal joint using Ni-Ti filler metal.
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