V. Pérez Herranz

Corrosion Behavior and Galvanic Coupling of Stainless Steels, Titanium, and Alloy 33 in Lithium Bromide Solutions

Abstract The corrosion resistance and galvanic behavior of three stainless steels (SS), Alloy 33, and titanium were analyzed in commercial lithium bromide (LiBr) heavy brine solutions used in heating and refrigerating systems, with and without additives, using potentiodynamic anodic polarization measurements. Corrosion rates were determined from the Tafel slopes and inhibitor effects were also analyzed. The highest corrosion currents were obtained in the less-concentrated LiBr solution and the most negative corrosion potentials were obtained in a chromate-inhibited LiBr brine. The most effective action of the inhibitor was observed on titanium while it was least effective for Alloy 33. Critical potentials were calculated at 100 μA/cm2, and it was observed that the chromate inhibitor did not improve the resistance of SS to pitting corrosion. Galvanic current and mixed potentials were calculated for all possible combinations of the tested materials from polarization curves according to the mixed potential t...

Galvanic Studies of Copper Coupled to Alloy 33 and Titanium in Lithium Bromide Solutions

Abstract Galvanic influence of Alloy 33 (UNS R20033) and titanium (Grade 2) on copper was studied in lithium bromide (LiBr) solutions (400, 700, and 850 g/L chromate containing commercial solution). Temperature effect was also analyzed by imposing a heating/cooling cycle to the samples during a 10-h period (from 25°C to 80°C at 0.5°C/min), during a 2-h period (from 80°C to 25°C at 0.5°C/min), and during the last 2 h (maintained at 25°C). The galvanic potential and the galvanic current were measured with a zero-resistance ammeter (ZRA) during the temperature cycle. Images of the electrode surfaces were captured simultaneously with the recorded electrochemical signal caused by corrosion processes without disturbing the electrochemical system. The experimental device consists of an electrochemical system with an horizontal electrochemical cell coupled to a microscope, camera, and a system of image acquisition. Copper is always the anodic element of the Cu-Alloy 33 pair; however, it behaves cathodically or an...

Corrosion Behavior and Galvanic Studies of Brass and Bronzes in Aqueous Lithium Bromide Solutions

Abstract The analysis of the corrosion of copper alloys (brass [Cu65/Zn35], bronze B10 [Cu90/Sn10], and bronze B5 [Cu85/Zn5/Sn5/Pb5]) and zinc in commercial lithium bromide (LiBr) heavy brine solutions, with and without additives, was analyzed using polarization curves. Corrosion rates were determined by the Tafel slope method. The inhibitor effect was analyzed in a commercial solution. Galvanic current and mixed potentials were determined using polarization curves according to the mixed potential theory. Zinc content in alloys displaced open-circuit potentials (OCP) toward more negative values following a linear relationship. The differences in the potentials of the materials increased with zinc content in the alloy in the different LiBr solutions. Generally, the highest current corrosion was obtained in 700 g/L LiBr solution at the most negative corrosion potentials. Chromate and lithium hydroxide (LiOH) presence in commercial LiBr solution produced complete inhibition on brass but this inhibitor effect...

Effect of Aqueous Lithium Bromide Solutions on the Corrosion Resistance and Galvanic Behavior of Copper-Nickel Alloys

Abstract The analysis of the corrosion of Cu-xNi alloys (x = 10 wt% to 30 wt%) and Cu and Ni metals in commercial lithium bromide (LiBr) heavy brine solutions, with and without additives, was perfo...

Effect of Nitrogen in Argon as a Shielding Gas on Tungsten Inert Gas Welds of Duplex Stainless Steels

Abstract The effect of nitrogen content in the argon shielding gas of tungsten inert gas (TIG) welding on the corrosion resistance of a duplex stainless steel (DSS; AISI 2205) was investigated usin...

Corrosion Behavior of Austenitic and Duplex Stainless Steel Weldings in Aqueous Lithium Bromide Solution

Abstract The corrosion behavior of three stainless steels UNS 14311, UNS 14429 (austenitic stainless steels [SS]), UNS 14462 (duplex SS) and their corresponding filler metals (alloys in form of wir...

Passive behaviour of stainless steels and nickel in LiBr solution at different temperatures

Abstract The aim of the present work was to study the passive behavior of different stainless steels in commercial LiBr heavy brine solution (850 g/L, which contains chromate as inhibitor), at different temperatures (25, 50, and 80°C). LiBr solutions are the most common medium in the refrigeration systems which uses the absorption technology. The materials tested were stainless steels EN 1.4591, with nominally (wt%) 33 Cr, 32 Fe, 31 Ni; EN 1.4562, an iron-nickel-chromium-molybdenum alloy with nitrogen addition; and two austenitic stainless steels EN 1.4311 and EN 1.4429. Pure nickel was also tested to study its influence in the alloys. Passive behaviour was estimated from the cyclic potentiodynamic polarization curves, analysing the pitting potentials, passive current densities and repassivating properties at different temperatures.