A comparative study on sintering behavior and microstructure of copper-cobalt-alloy using conventional sintering and FAST

In this study, Copper-Cobalt-based granulated and non-granulated powders were investigated using Field-Assisted Sintering Technology (FAST) and conventional sintering. Phase composition analysis via Rietveld refinement of X-Ray Diffraction data demonstrated that the sintering method critically influenced the microstructural evolution. Conventional sintering of one of the investigated compositions (BOND1H) led to the formation of the FeCo intermetallic due to a prolonged exposure to high temperatures. On the other hand, FAST processing preserved discrete iron and cobalt phases. The FAST process exhibited superior efficacy for non-granulated powders, achieving 91.4% theoretical density in one of the samples (BOND2R) with minimal defects, compared to granulated systems where binder decomposition induced porosity. Remarkably, FAST-processed BOND2R composition attained hardness values (245 ± 32 HRB) equivalent to the conventional counterparts (240 ± 10 HRB) despite differences in densification. These results underscore the dual influence of sintering strategy and powder morphology on microstructural control, defect formation, and mechanical performance in Copper-Cobalt-based systems. • FAST and conventional sintering compared for granulated and non-granulated copper-cobalt alloys. • FAST sintering efficiently densifies non-granulated powders, while granulated powders develop defects from binder decomposition. • FAST sintering enhances efficiency and significantly reduces processing time for copper-cobalt alloys. • Prolonged conventional sintering promotes Iron diffusion in cobalt, forming FeCo intermetallic, while FAST preserves initial phases separately.