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| Abstract No.: |
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Scheduled at:
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Tuesday, June 19, 2007, Brüssel 1:40 PM
Fügen von Hartstoffen, Hartmetallen, Cermets
Joining of cemented carbides, hard metals, cermets
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| Title: |
Active brazing filler metals containing TiC nanoparticles formed by in-situ decomposition of organic binder systems
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| Authors: |
Hans Rudolf Elsener* / EMPA, Switzerland
Hans Rudolf Elsener / Empa / Laboratory for Joining and Interface Technology, Switzerland
Ulrich E. Klotz/ Empa / Laboratory for Joining and Interface Technology, Switzerland
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| Abstract: |
The effect of binder and graphite content on microstructure and erosion resistance of a Cu-Sn-Ti-Zr active brazing filler metal suitable for active brazing of diamond and cBN grit to metal has been investigated. The intention was to improve the erosion resistance measured in sand blasting tests due to the precipitation of finely dispersed Ti carbide particles. Additions of cellulose nitrate binder (0.4 - 3 wt%) and graphite (5 - 15 at%), respectively have been mixed with filler metal powder and octyl acetate to form a paste and melted in a vacuum furnace at 930°C for 10 min. The effect of binder content on microstructure has been investigated by XRD, SEM and TEM, showing the formation of nanosized TiC particles in both Cu-rich phase and CuSn3Ti5 intermetallic regions of the alloy. Erosion tests showed a decrease of erosion rate and weight loss as far as 22% or 30%, respectively with 3 wt% cellulose nitrate in filler metal. Comparisons were made with graphite containing samples, which however showed residual carbon due to incomplete reaction with filler metal. Therefore, no significant improvement was achieved in this case. By a variation of binder type and content it is expected to tailor properties of the filler metals in terms of erosion resistance necessary for a new generation of superabrasive tools.
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