The soft magnetic iron-nickel alloys with 50 wt nickel were produced by powder metallurgy route. High purity and fine particle size iron and nickel powders were blended in Turbular mixer and compacted uniaxially with compaction pressure of 700 MPa. The Fe and Ni were mixed in ratio of 1:1 and then nano-size elemental boron (0 - 0.75 wt ) was added with the increment of 0.25. The green samples were sintered at 1330 oC in Argon atmosphere with sintering time of 2 and 4 hrs. Sintering time and temperature effect on densification, mechanical properties and microstructure were investigated. Furthermore, effect of boron additive on microstructure, mechanical properties and densification were also studied. Samples with higher sintering time showed better density and hardness. In X-ray diffraction patterns of sintered samples, Fe and Ni peaks disappeared which indicates the complete alloy formation and only peaks of γ-FeNi phase detected. The addition of elemental nano-size boron has shown significant effect on densification and mechanical properties. © 2019 Elsevier Ltd. All rights reserved.