New concept of the mechanism of intergranular corrosion of stainless steels

作者：Kasparova O V^*; Baldokhin Yu V

来源：Protection of Metals, 2007, 43(3): 235-240.

DOI：10.1134/S0033173207030058

The electronic structure of chromium-nickel austenite stainless steels of type X20H20 and X10H20, in particular, added with 4 to 6% Si, is studied using nuclear gamma-resonant (Mossbauer) spectroscopy. The structure varies significantly depending on the chromium and silicon content. Low-chromium steels are used for the modeling of chromium-depleted boundary zones that neighbor chromium-rich excess phases. Eventually, a mechanism of the intergranular corrosion of stainless steels that takes into account the changes in the electronic structure of the chromium-depleted boundary zones is first suggested. These changes in the chemisorption interaction of the iron carcass ions with corrosive components of the medium, cannot but affect the zones' stability. It is this interaction that synergistically intensifius the intergranular corrosion of austenite stainless steels containing combinations of silicon dopant and carbon impurity, or the phosphorus and carbon impurities.

• 出版日期2007-6