Spark plasma sintering of Fe–Si–B–Cu–Nb / Finemet based alloys

Abstract The influence of mechanical alloying (MA) and spark plasma sintering (SPS) processing parameters on the microstructure, magnetic and mechanical properties of Finemet (Fe73.5Cu1Nb3Si13.5B9) type alloys was investigated. Finemet alloy powder was obtained via mechanical alloying of elemental powders for 30 h, 60 h, 90 h, and 120 h with ball to powder ratio (BPR) of 10:1 and 15:1. The milled powders were consolidated using the SPS process. The XRD patterns confirm the presence of the α-Fe3Si phase in all Finemet alloys, also broadening of the (110) peak of α-Fe3Si was observed with increasing milling time. The microhardness of Finemet alloys increases with increase in milling time primarily due to a decrease in grain size. All samples show good saturation magnetization (Ms), 120h sample exhibiting the highest Ms of 166 emu/g, however coercivity increases with increasing milling time. Additionally, α-Fe3Si crystal size decreases with increasing the BPR primarily due to higher impact energy.