Details

Autor(en) / Beteiligte

• Ma, Ming-yu
• He, Chun-lin
• Liu, Hou-long
• Chen, Li-qing

Titel

Influence of Cerium and Tungsten Addition on the Passive Behaviour of 444-type Ferritic Stainless Steels

Ist Teil von

• International journal of electrochemical science, 2019-03, Vol.14 (3), p.2277-2289

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2019

Link zum Volltext

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• The surface passivity properties of conventional 444-type ferritic stainless steel (FSS), Ce-containing 444-type FSS and W-Ce-containing 444-type FSS were studied in a 1.0 mol/L H2SO4+0.5 mol/L NaCl solution by employing electrochemical impedance spectroscopy (EIS) analysis, the potentiodynamic polarization test and capacitance measurement. The potentiodynamic polarization curves revealed that the Ce and/or W addition did not affect the pitting potential Ep and the corrosion potential Ecorr, whereas the corrosion current density icorr and the passive current density ip were decreased significantly. The morphological observation of the specimens after polarization suggested that alloying with Ce and W decreased the number of pitting sites and inhibited the active dissolution of pits. The Mott-Schottky analysis revealed that all the oxide layers formed on FSS behaved as n-type semiconductors at the potential range of 0.3–0.8 VSCE and that the donor concentration Nd in the passive film increased with Ce and W alloying. In addition, the diffusivity values of the donors in FSS passive films were calculated based on the combination of capacitance measurements and PDM theory. The EIS analysis showed that the Ce-W-containing stainless steel presented lower polarization resistance values.