In order to improve the sinterability of compacts of water-atomized high-speed steel (HSS) powders the addition of small amounts of graphite to the mixture before compaction was proposed by Uspenski [2], and Kulkarni, etal. [5]. At the same time, boron is the activating element used to increase the densification of iron-base materials during sintering. According to [5] boron is substantially more active than graphite. Boron can be added to the charge in the
form of amorphous boron powder [5], or as a component of a complex addition containing 10-30% B and 70-90% Ni [6] or of the intermetallic Ni3Nb [7, 8]. In the present work the initial material was the −400 μm fraction of the gasatomized steel powder R6M5K5 with an activating addition of (70% Ni − 30% B). The activator was added to the powder when it was mixed with liquid paraffin, used as a binder-plasticizer during ingot compaction which was carried out at a pressure of 700 MPa.