Profiling interfacial reaction features between diamond and Cu-Sn-Ti active filler metal brazed at 1223 K

Abstract

• When the TiH 2 content is below 5 wt.%, completely uncoated and partially coated diamond particles with sharp edges can still be observed. When above 5 wt.%, all diamond particles are completely coated, indicating sufficient wettability has been achieved. • The interfacial reaction layer is found to be composed of TiC, the thickness of which is demonstrated to increase as a function of TiH 2 content, arriving at the peak value of 1.70 µm and remaining almost constant afterwards. • Further increasing TiH 2 content above 5 wt.% is unnecessary or even harmful, as it may encourage the formation of brittle Cu 41 Sn 11 phase, leading to significantly reduced wear resistance and potentially downgraded grinding efficiency. Diamond/Cu-Sn-Ti composites have been successfully prepared by cold-press forming in conjunction with high-temperature vacuum active brazing at 1223 K. Ensuing wetting behaviors between diamond and filler metal, interfacial characteristics of the reaction layer, and wear resistance of the bulky composite have been fully investigated. It is revealed that all diamond particles can only be fully coated when the TiH 2 content exceeds 5 wt%, below which sharp edges on diamond can still be observed. The interfacial reaction layer is found to be composed of TiC, the thickness of which is demonstrated to increase as a function of TiH 2 content, arriving at the peak value of 1.70 µm and remaining almost constant afterwards. It is further shown that the maximum wear resistance occurs approaching 5 wt% TiH 2 content. Potential mechanisms responsible for such interesting phenomena have been postulated.