Corrosion and electrochemical behavior of stainless steels under cathode polarization in nitric acid solutions

1960 ◽  
Vol 9 (7) ◽  
pp. 1092-1097 ◽  
Author(s):  
E. N. Mirolyubov ◽  
M. M. Kurtepov ◽  
N. D. Tomashov
Keyword(s):  
Nitric Acid ◽  
Stainless Steels ◽  
Electrochemical Behavior ◽  
Acid Solutions ◽  
Cathode Polarization ◽  
Nitric Acid Solutions

scholarly journals Alternative to Nitric Acid Passivation of 15-5 and 17-4PH Stainless Steel Using Electrochemical Techniques

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2836 ◽  
Author(s):  
María Lara-Banda ◽  
Citlalli Gaona-Tiburcio ◽  
Patricia Zambrano-Robledo ◽  
Marisol Delgado-E ◽  
José A. Cabral-Miramontes ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Citric Acid ◽  
Stainless Steels ◽  
Electrochemical Techniques ◽  
Passive Layer ◽  
Localized Corrosion ◽  
Acid Solutions ◽  
Protective Oxide ◽  
Nitric Acid Solutions ◽  
Machining Operations

Increasingly stringent environmental regulations in different sectors of industry, especially the aeronautical sector, suggest the need for more investigations regarding the effect of environmentally friendly corrosion protective processes. Passivation is a finishing process that makes stainless steels more rust resistant, removing free iron from the steel surface resulting from machining operations. This results in the formation of a protective oxide layer that is less likely to react with the environment and cause corrosion. The most commonly used passivating agent is nitric acid. However, it is know that high levels of toxicity can be generated by using this agent. In this work, a study has been carried out into the electrochemical behavior of 15-5PH (precipitation hardening) and 17-4PH stainless steels passivated with (a) citric and (b) nitric acid solutions for 60 and 90 min at 49 °C, and subsequently exposed to an environment with chlorides. Two electrochemical techniques were used: electrochemical noise (EN) and potentiodynamic polarization curves (PPC) according to ASTM G199-09 and ASTM G5-13, respectively. The results obtained indicated that, for both types of steel, the passive layer formed in citric acid as passivating solution had very similar characteristics to that formed with nitric acid. Furthermore, after exposure to the chloride-containing solution and according with the localization index (LI) values obtained, the stainless steels passivated in citric acid showed a mixed type of corrosion, whereas the steels passivated in nitric acid showed localized corrosion. Overall, the results of the R n values derived show very low and similar corrosion rates for the stainless steels passivated with both citric and nitric acid solutions.

scholarly journals Crevice Corrosion of Type 304L and 316L Stainless Steels in Nitric Acid Solutions

2002 ◽  
Vol 51 (4) ◽  
pp. 165-172 ◽  
Author(s):  
Yuko Arai ◽  
Katsumi Mabuchi ◽  
Takashi Honda ◽  
Saburo Shouji ◽  
Tsunenobu Yokosuka ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Stainless Steels ◽  
Crevice Corrosion ◽  
Acid Solutions ◽  
Nitric Acid Solutions
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