received by the International Bureau on 27 November 2017 (27.1 1.2017)

1. A method of manufacturing sintered elements having a matrix of iron or iron-alloy, in which a homogenous mixture intended for forming compacts contains iron powder or iron-alloy powder of carbon content lower than 0.5 wt.%, additives or master alloys, lubricants, liquid-phase inducing additives and said compacts are heated in a protective atmosphere, sintered isothermally and cooled, characterized in that said mixture intended for making sintered elements contains 0.05 to 1.00% by weight of boron which is introduced into the mixture in an active form, where the active form is an elementary form, or a form of an alloy, or a form of a chemical compound, and said forms of boron are capable of generating a liquid phase as a result of a eutectic reaction with the matrix or capable of self-melting and generating a boron-containing liquid phase even before the compact reaches the sintering temperature, said mixture contains at least one of nitrides, excluding boron nitride, selected from the nitrides having their melting points or decomposition temperatures higher than the sintering temperature which is in the range of 1100°C-1300°C, moreover, said nitrides are in particular Si, Cr, Ti, Al, Mo, Mn, V nitrides, furthermore, the amounts of the nitrides and boron in the mixture are determined in such a manner that the molar ratio of nitrogen to boron atoms is between 0.05 and 2.15. 2. The method according to claim 1, characterized in that the molar ratio of nitrogen to boron atoms is between 0.1 to 1.4.

3. The method according to claim 1, characterized in that the heating of the compacts is carried out at a rate of not more than 30° C/min., and the isothermal sintering is carried out in the gaseous protective atmosphere for up to 60 min. 4. The method according to claim 3, characterized in that the heating of the compacts is carried out at a rate of not more than 10° C/min., and the isothermal sintering is carried out for up to 10 - 40 min.