The role of binder content on microstructure and properties of a Cu-base active brazing filler metal for diamond and cBN

The bonding for different filler metal compositions to maintain the tool performance during service was investigated. Cellulose nitrate (CN), because of its low thermostability and formation of low volatile products, with a nitrogen content of < 12.3 wt% was used as binder for the filler metal powder (Cu-14Sn-10Ti-1.5Zr). It was found that thermal degradation of CN at 10 K/min in nitrogen began with a denitration at 207°C, followed by the pyrolysis at 213°C with a char yield of 5.3wt%. The surface of the individual samples showed different morphology after brazing. It was also found that by increasing the binder content or in the case of graphite additions the surface became smoother and more regular.