PROCESSING AND SURFACE PROPERTIES OF BASED ON IRON SINTERED ALLOYS AFTER PLASMA NITRIDING TREATMENT

Sintered parts based on iron and alloyed powders have been widely used in automotive industry. In order to enhance surface properties of those PM (Powder Metallurgy) alloys like hardness and abrasive wear, nitriding and carbonitriding treatment are applied. One of the main problem of PM chemical heat treatment alloys is their porosity degree. In the experiments Fe-Ni-Cu-Mo and Fe-Mo sintered structural parts modified by boron were made. Boron activates the sintering process which results in their considerable consolidation in the sintering at 1200 C for 60 min. in the atmosphere of hydrogen. The experiments are related to the production of sintered structural elements based on iron powder – NC 100,24 as well as Astaloy Mo (Fe-Mo) and Distaloy SA (Fe-Ni-Cu-Mo) modified by 0.2 wt%, 0,4 wt % and 0,6 wt % B. P/M parts were obtained by mixing powders said above, followed by compacting at 600 MPa pressure and sintered at 1200 C during 60 minutes time in hydrogen atmosphere. Selected sintered parts were plasma nitrided at 560 C during 4 hours time. The effect of plasma nitriding on the microstructure and surface properties of samples has been analyzed