Electrochemical Testing for Pitting Corrosion Above Ambient Temperatures Using the Syringe Cell

CORROSION ◽  
10.5006/3854 ◽  
2021 ◽  
Author(s):  
Anup Panindre ◽  
Gerald Frankel
Keyword(s):  
Pitting Corrosion ◽  
Specimen Surface ◽  
Hot Plate ◽  
Pitting Potential ◽  
Ambient Temperatures ◽  
Electrochemical Testing ◽  
Different Temperatures ◽  
Critical Pitting Temperature ◽  
Constant Potential ◽  
Passive Alloys

The syringe cell method has been further developed to evaluate the temperature dependence of pitting corrosion in passive alloys having critical pitting temperature above ambient without artifacts associated with crevice corrosion. The pitting potential of commercially available duplex stainless steel type 2205 was measured at different temperatures by using a hot plate to heat the specimen. Breakdown potentials decreased by about 1 V at test temperatures above 50 °C. The critical pitting temperature (CPT) of the alloy was determined to be between 54 °C and 59 °C by scanning the temperature of the specimen surface during a constant potential hold. In all experiments, pits were observed in the area defined by the electrolyte droplet in contact with the specimen surface. The CPT of the alloy determined using a more conventional approach mentioned in ASTM Standard G48 Method C was 55 °C.

Corrosion evaluation of Ti-6Al-4V parts produced with electron beam melting machine

2016 ◽  
Vol 22 (2) ◽  
pp. 322-329 ◽  
Author(s):  
Dana H. Abdeen ◽  
Bruce R. Palmer
Keyword(s):  
Electron Beam ◽  
Corrosion Behavior ◽  
Pitting Corrosion ◽  
Electron Beam Melting ◽  
Saturated Calomel Electrode ◽  
Nacl Solution ◽  
Pitting Potential ◽  
Exterior Surface ◽  
Content Type ◽  
Critical Pitting Temperature

Purpose This paper aims to evaluate the corrosion behavior of Ti-6Al-4V parts produced with electron beam melting (EBM) machine and compare it with wrought Ti-6Al-4V alloy. Design/methodology/approach Potentiodynamic and potentiostatic tests were applied on EBM Ti-6Al-4V in 3.5 per cent mass NaCl solution to determine the pitting potential and critical pitting temperature (CPT). A relation between pitting potential and temperature was established for EBM Ti-6Al-4V alloy by conducting potentiodynamic testing under different temperatures. CPT was also measured for EBM Ti-6Al-4V alloy in 3.5 per cent mass NaCl solution at a standard potential of 800 mV vs saturated calomel electrode (SCE). The same tests were performed on wrought Ti-6Al-4V for comparison purposes. Moreover, CPT for EBM Ti-6Al-4V alloy was measured in 3.5 per cent mass NaCl solution of different pH of 2.0, 5.7 and 10.0 to examine the effect of aggressive conditions on the pitting corrosion of EBM alloy. Findings Potentiodynamic test resulted in a relatively high pitting potential of EBM alloy, which was close to the pitting potential of wrought alloy even at higher temperatures. In addition, EBM samples did not pit when potentiostatic test was performed at 800 mV vs SCE, even at high and low values of pH. Originality/value EBM Ti-6Al-4V alloy has been increasingly playing an important role in aerospace, automobile and industrial fields. The technique and conditions of manufacturing form voids and increase roughness of the exterior surface of EBM objects, which might increase the tendency to initiate pitting corrosion within its holes and surface folds. This article shows that, despite surface variations and porosity in EBM Ti-6Al-4V alloy, the material maintained its corrosion resistance. It was found that the corrosion behavior of EBM alloy was close to that of the conventionally made wrought Ti-6Al-4V alloy.

Effect of Passivation on Pitting Corrosion of 316L Stainless Steel in Concentrated Seawater

2012 ◽  
Vol 472-475 ◽  
pp. 127-131
Author(s):  
Feng Jun Lang ◽  
Ying Ma ◽  
Jian Rong Liu ◽  
Xian Qiu Huang ◽  
Mou Cheng Li
Keyword(s):  
Stainless Steel ◽  
Pitting Corrosion ◽  
Anodic Polarization ◽  
316L Stainless Steel ◽  
Pitting Potential ◽  
Critical Pitting Temperature

The influence of passivation on pitting corrosion of 316L stainless steel in concentrated seawater was investigated by using cyclic anodic polarization and critical pitting temperature. The results indicated that the pitting potential of passivated specimen was higher than that of matrix specimen in concentrated seawater at 25°C and 85°C. Critical pitting temperature value of passivated specimen was 56°C, which was much higher than 11°C for matrix specimen. Pitting corrosion occurred in the formed pit of passivated specimen, and metastable pit, lacy cover and new pit were observed in pit morphology.

Effect of Chloric Ions and Temperature on the Pitting Corrosion Behavior of Supermartensitic Stainless Steel in CO2-Saturated Chloride Solution

2012 ◽  
Vol 538-541 ◽  
pp. 2342-2345
Author(s):  
Jun Li ◽  
Dong Ye ◽  
Yong Mei Chen ◽  
Jie Su ◽  
Kun Yu Zhao
Keyword(s):  
Stainless Steel ◽  
Corrosion Behavior ◽  
Pitting Corrosion ◽  
Chloride Solution ◽  
Polarization Measurement ◽  
Ion Concentration ◽  
Pitting Potential ◽  
Supermartensitic Stainless Steel ◽  
Different Temperatures ◽  
Logarithmic Relation

Abstract. The pitting corrosion behavior of two kinds (W and Cu-free; W and Cu-bearing) of supermartensitic stainless steels (SMSS) were studied in CO2-saturated chloride solution with three chloric ion concentration: 21200, 50000, 100000ppm, and four different temperatures:19, 40, 60, 80°C by potentiodynamic polarization measurement. The results indicate that the pitting potential decreased with temperature increasing, and in a logarithmic relation with the chlorine concentration in both alloys. The pitting potential of supermartensitic stainless steel is increased by together adding tungsten and copper.

Experimental Study of Propagation Stage of Pitting Corrosion of 20Cr13 Steel

2008 ◽  
Vol 38 ◽  
pp. 238-247
Author(s):  
A.D. Davydov ◽  
V.S. Shaldaev
Keyword(s):  
Pitting Corrosion ◽  
Open Circuit Potential ◽  
Corrosion Potential ◽  
Ph Value ◽  
Open Circuit ◽  
Effect Of Temperature ◽  
Pitting Potential ◽  
Free Corrosion Potential ◽  
External Power Source ◽  
Corrosion Of Steel

The initiation and development of pitting corrosion of steel 20Cr13 in the NaCl solutions with various concentrations, temperatures, and pH values are studied under the potentiostatic conditions and at the free-corrosion potential. The pitting and repassivation potentials are determined using the method of cycling voltammetry. In spite of the fact that thus determined pitting potential is more positive than the corrosion potential (the open-circuit potential Eo.c.), the long-term experiments, which were performed at the free-corrosion potential, showed that pitting corrosion takes place without imposing a potential using an external power source. It is concluded that the probability of pitting corrosion of steel should be determined by comparing the corrosion potential (the open-circuit potential) with the repassivation potential Erp. Steel 20Cr13 is prone to the pitting corrosion, because Erp is more negative than Eo.c.. In the potentiostatic experiments, the variation of the depth and diameter of pits and their number with the time and the effect of temperature and electrode rotation on the pit propagation are studied. The results, which were obtained at the free-corrosion potential, are much less reproducible. In this case, in contrast to the potentiostatic conditions, the pit depth increased only slightly and the pit width increased to a larger extent. The effect of concentration, pH value, and temperature of NaCl solutions on the pit propagation is considered. It is concluded that the data on the development of pitting corrosion under the potentiostatic conditions can be hardly extended to the conditions of free corrosion potential.

Influence of Sigma Phase Precipitation on Pitting Corrosion of 2507 Super-Duplex Stainless Steel

2010 ◽  
Vol 658 ◽  
pp. 380-383 ◽  
Author(s):  
Ying Han ◽  
De Ning Zou ◽  
Wei Zhang ◽  
Jun Hui Yu ◽  
Yuan Yuan Qiao
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Ambient Temperature ◽  
Duplex Stainless Steel ◽  
Pitting Corrosion ◽  
Super Duplex Stainless Steel ◽  
Phase Precipitation ◽  
Pitting Potential ◽  
Σ Phase ◽  
Pitting Corrosion Resistance

Specimens of 2507 super-duplex stainless steel aging at 850°C for 5 min, 15 min and 60 min were investigated to evaluate the pitting corrosion resistance in 3.5% NaCl solution at 30°C and 50°C. The results are correlated with the microstructures obtained with different aging time. The precipitation of σ phase remarkably decreases the pitting corrosion resistance of the steel and the specimen aged for 60 min presents the lowest pitting potential at both 30°C and 50°C. With increasing the ambient temperature from 30°C to 50°C, the pitting potential exhibits a reduction tendency, while this tendency is less obviously in enhancing the ambient temperature than in extending the isothermal aging duration from 5 to 60 min. SEM analysis shows that the surrounding regions of σ phase are the preferable sites for the formation of corrosion pits which grew up subsequently. This may be attributed to the lower content of corrosion resistance elements in these regions formatted with σ phase precipitation.

Temperature sensitivity of simulated soils with biochars produced at different temperatures

Soil Research ◽  
2019 ◽  
Vol 57 (3) ◽  
pp. 294 ◽  
Author(s):  
Xiaojie Wang ◽  
Guanhong Chen ◽  
Renduo Zhang
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Temperature Sensitivity ◽  
Pyrolysis Temperature ◽  
Soil C ◽  
Ambient Temperatures ◽  
C Pools ◽  
C Cycle ◽  
Microbial Enzyme ◽  
Different Temperatures

The temperature sensitivity of multiple carbon (C) pools in the soil plays an important role in the C cycle and potential feedback to climate change. The aim of this study was to investigate the temperature sensitivity of different biochars in soil to better understand the temperature sensitivity of different soil C pools. Biochars were prepared using sugarcane residue at temperatures of 300, 500 and 800°C (representing different C pools) and C skeletons (representing the refractory C pool in biochar) were obtained from each biochar. The sugarcane residue, biochars and C skeletons were used as amendments in a simulated soil with microbes but without organic matter. The temperature sensitivity of the amended soils was characterised by their mineralisation rate changes in response to ambient temperatures. The temperature sensitivity of treatments with relatively refractory biochars was higher than that with labile biochars. The temperature sensitivity of treatments with biochars was lower than for their corresponding C skeletons. The different temperature sensitivity of treatments was attributable to the different internal C structures (i.e. the functional groups of C=C and aromatic structure) of amendments, determining the biodegradability of substrates. Dissolved organic matter and microbial enzyme activity of biochars were lower than those of corresponding C skeletons, and decreased with increasing pyrolysis temperature. The temperature sensitivities of treatments with biochars, C skeletons and sugarcane residue were negatively correlated with the properties of dissolved organic matter and microbial enzyme activities (especially dehydrogenase) in soil.

scholarly journals Pitting Corrosion Resistance on Annealing Treated Super Duplex Stainless Steel S32750

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 294
Author(s):  
Shuang Liu ◽  
Chaohua Yue ◽  
Xi Chen ◽  
Qiuhua Zhu ◽  
Yiyou Tu
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Duplex Stainless Steel ◽  
Pitting Corrosion ◽  
Annealing Temperature ◽  
Super Duplex Stainless Steel ◽  
Boundary Area ◽  
Pitting Potential ◽  
Pitting Corrosion Resistance ◽  
Equivalent Number

The pitting corrosion resistance of S32750 super duplex stainless steel, annealing treated at temperatures of 950–1200 °C for 20–60 min, was investigated using potentiodynamic polarization tests. The results show that the volume fractions of ferrite in the S32750 duplex stainless steel increased from 48.9% to 68.4% as annealing temperatures increased from 950 to 1200 °C. The pitting potential of the sample increased first and then decreased from an annealing temperature of 950 to 1050 °C, and the highest pitting potential was observed after annealing at 1050 °C for 35 min. The pitting corrosion resistance of S32750 stainless steel is due to the combination of pitting resistance equivalent number (PREN) value, phase fraction and grain boundary area fraction, and the imbalance of corrosion potential.

Pitting Resistance of Domestic Super Martensitic Stainless Steel 00Cr13Ni5Mo2

2013 ◽  
Vol 834-836 ◽  
pp. 370-373
Author(s):  
Shi Dong Zhu ◽  
Jin Ling Li ◽  
Hai Xia Ma ◽  
Li Liu
Keyword(s):  
Stainless Steel ◽  
Corrosion Rate ◽  
Pitting Corrosion ◽  
Martensitic Stainless Steel ◽  
Pitting Potential ◽  
Electrochemical Technology ◽  
Super Martensitic Stainless Steel ◽  
Nacl Concentration ◽  
Made In China ◽  
Made In

Pitting resistance of super martensitic stainless steel 00Cr13Ni5Mo2 made in China has been investigated by employing electrochemical technology and chemical immersion methods. The results showed that pitting potential of super martensitic stainless steel decreased with the increasing of NaCl concentration and temperature, respectively. And corrosion rate of super martensitic stainless steel increased with the increasing of temperature. Furthermore, compared to super martensitic stainless steel made in Japan, the domestic one was better in terms of pitting potential, pitting corrosion rate and the density of the pits, but worse in terms of the depth of the pits.

Sign in / Sign up

Export Citation Format

Share Document