This paper describes the sintering of an injection molded 17-4 PH stainless steel with additions of nickel boride (NiB), with the aim of producing high mechanical properties. Boron is evaluated as the best sintering enhancing element in terms of densifying the iron-based materials by formation the liquid phase. Sintered density and mechanical properties were increased with the increased amount of NiB while sintering time and temperature were decreased. Sintering to full density and highest mechanical properties were obtained with the addition of 1 wt% NiB at 1280 degrees C for 45 min. The formation of borides caused the increase of mechanical properties. This material may therefore find a wider technological application, because of its improved mechanical properties. (c) 2005 Springer Science + Business Media, Inc.