SINTERING MECHANISM OF IRON-POWDER WITH MICROADDITIONS OF BORON

The effect of boron on the sintering of iron powder war investigated. Boron (0-400 ppm) was added to high-purity iron powder of the German f irm ''Mannesmann.'' Powder mixtures were pressed to compacts of identi cal density and sintered at different temperatures in different atmosp heres. The results indicated the absence of a liquid phase and no infl uence of boron in the high-temperature stage of sintering. However, bo ron additions substantially improved sintering at low temperatures (up to 800 degrees C) due to an effect on the interparticle contacts. Wit h a properly selected sintering regime, microadditions of boron substa ntially increase the density of sintered ingots.