Liquid Phase Sintering of a Boron Alloyed Austenitic Stainless Steel

It is well known that PM stainless steels have lower corrosion resistance than the corresponding wrought steels, since they are affected by the presence of the open porosity. A way to obtain a surface densification is the addition of a small quantity of boron (from 0,3 to 0,5%wt.) to the stainless steel. The presence of boron produces a liquid phase phenomenon that results in a final microstructure consisting of a boron-rich phase network surrounding the stainless steels grains. Close to the surface, a boron-free layer was observed in which pores are very few, closed and round. This leads to an improvement in the steel corrosion resistance.