Corrosion Behavior Of Copper Alloy Research Articles

Correlation of temperature with galvanic corrosion behaviour of copper alloys based on wire beam electrode

ABSTRACTGalvanic corrosion behaviour of copper and copper alloys in chloride solution (0.6 M NaCl) under different temperature conditions (35°C, 55°C and 80°C) was investigated by the wire beam electrode (WBE) method. It was found that the average galvanic current of the Cu and Cu–Sn alloy, which shifted from the cathode at 35°C to the anode at 80°C, increased as temperature increased during the immersion time. In contrast, the average galvanic current of Cu–Zn alloy can be ranked as 35°C > 55°C > 80°C. A sudden conversion was that the anode average current of Cu–Zn alloy at 35, 55°C changed into the cathode when the immersion time lasted untill 3 h at 80°C. The results indicate that it is feasible to study the corrosion behaviour under the different temperature environment with the WBE method.

Accelerated Degradation Test and Predictive Failure Analysis of B10 Copper-Nickel Alloy under Marine Environmental Conditions.

This paper studies the corrosion behavior of B10 copper-nickel alloy in marine environment. Accelerated degradation test under marine environmental conditions was designed and performed based on the accelerated testing principle and the corrosion degradation mechanism. With the prolongation of marine corrosion time, the thickness of Cu2O film increased gradually. Its corrosion product was Cu2(OH)3Cl, which increased in quantity over time. Cl− was the major factor responsible for the marine corrosion of copper and copper alloy. Through the nonlinear fitting of corrosion rate and corrosion quantity (corrosion weight loss), degradation data of different corrosion cycles, the quantitative effects of two major factors, i.e., dissolved oxygen (DO) and corrosion medium temperature, on corrosion behavior of copper alloy were analyzed. The corrosion failure prediction models under different ambient conditions were built. One-day corrosion weight loss under oxygenated stirring conditions was equivalent to 1.31-day weight loss under stationary conditions, and the corrosion rate under oxygenated conditions was 1.31 times higher than that under stationary conditions. In addition, corrosion medium temperature had a significant effect on the corrosion of B10 copper sheet.

Electrochemical and Salt Spray Corrosion Behavior of Copper Alloy Contact Wires in Chloride Solution

The effect of different alloying elements on corrosion behavior of copper alloys was investigated using electrochemical corrosion and salt spray corrosion test in NaCl solution. Cu-Ag has the most stable corrosion current in the potentiostatic scanning test, exhibiting a better corrosion resistant performance. It can be analyzed from corrosion surface morphologies that Cu-Ag presents exfoliation corrosion mechanism while Cu-Sn shows crevice corrosion mechanism. Cu-Mg has a complex corrosion process caused by multiple corrosion mechanism. In the salt spray corrosion test, the corrosion degree of Cu-Ag is lighter than those of Cu-Sn and Cu-Mg after 24h test. Therefore, the Cu-Ag alloy exhibits the best corrosion resistance in chloride solution.

Corrosion behaviour of bronze in urban environments: influence of tin content

In this paper, the influence of the tin content on the corrosion behaviour of copper alloys was investigated. Three different bicomponent bronze alloys were exposed to a natural urban environment. The kinetic corrosion processes and the patina properties were monitored using the open circuit potential, electrochemical impedance spectroscopy and spectrocolorimetry. Results show that the bronze corrosion behaviour improves upon increasing the tin content. In addition, the mechanism of the patina formation is different for the three alloys.

Field studies of corrosion behaviour of copper alloys in natural seawater

Eight copper alloys were tested in a one-year field deployment in the North Atlantic Ocean. The corrosion behaviour was characterized by weight loss, optical and electronic microscopy analyses. The biofouling performance was quantified in terms of the biomass accumulation. The testing program included specimens in tensioned and untensioned configurations, as well as a set for seasonal deployments. The seasonal corrosion rates were 140% higher, and the rates of tensioned specimens were 39% higher than those of the untensioned specimens after 12 months of deployment. Good biofouling resistance was observed for all but one alloy, which exhibited heavy fouling by barnacles.

Corrosion behavior of copper alloys in chloride media

The potentiodynamic polarization behavior of copper alloys in chloride solutions (1 M NaCl) of different pH’s (6.5 and 10) was investigated. Three commercial alloys of nominal composition Cu–30Ni (Cu–Ni), Cu–30Zn (Cu–Zn) and 90Cu–8Al–2Fe (Cu–Al) were considered. Results at pH of 6.5 showed no evidence of passivity with polarization behavior being dominated by the Cu component. At pH of 10, however, some evidence of limited passivity was seen. Passivity was more evident in buffered chloride (pH 10), in particular for Cu–Zn which showed remarkable passive behavior over a wide potential range. A sudden increase in the current density occurred when the anodic potential exceeded a certain critical potential, i.e., film breakdown potential. The results of these experiments are discussed in reference to potential–pH (Pourbaix) diagrams of the alloying elements.

銅合金の流れ誘起局部腐食に及ぼすNiおよびBeの影響

銅合金の流れ誘起局部腐食に及ぼすNiおよびBeの影響

熱交換器用銅合金の腐食挙動

熱交換器用銅合金の腐食挙動

The corrosion behavior of copper alloys, stainless steels and titanium in seawater

Effects of mass transport, corrosion products and biofilm formation on corrosion kinetics of five copper alloys, four stainless steels and titanium grade 2 exposed to natural and artificial seawater were determined. Corrosion current density ( i corr), anodic ( b a) and cathodic ( b c) Tafel slopes were determined from analysis of polarization curves recorded in the vicinity of the corrosion potential ( E corr) under controlled mass transport conditions as a function of exposure time. Rotating cylinder electrode experiments demonstrated that E corr and corrosion rate for stainless steels and titanium were independent of mass transport. For copper alloys i corr depended linearly on rotation speed r 0.7, while E corr was independent of mass transport. These results indicate that both cathodic and anodic reactions for stainless steels and titanium are under charge transfer control, whereas these reactions are under mass transport control for copper alloys. Corrosion rates of copper alloys were also obtained using linear polarization and weight loss. Corrosion rates obtained with the two methods agreed for exposures in artificial seawater. In natural seawater, corrosion rates determined with linear polarization underestimated corrosion rates from weight loss data by a factor of two or more. Environmental and traditional scanning electron microscopy coupled with energy-dispersive X-ray analyses were used to document surface topography, bacterial colonization and form of corrosion after removal of corrosion products. De-alloying of all copper alloys occurred in natural seawater. Intergranular corrosion was observed for 70Cu-30Ni alloy under elliptical deposits of embedded diatoms. De-alloying and intergranular corrosion did not occur in artificial seawater. Sulfides produced by bacteria may have accelerated attack of nickel in grain boundaries of 70Cu-30Ni alloy.

An Electrochemical Study of Copper Alloys In Chloride Solutions

An electrochemical investigation, involving free corrosion potential measurements and potentiodynamic polarisation measurements on fresh and corroded surfaces, was carried out in Sodium chloride solutions on cupronickels and special brasses, both well-suited classes of matenals for extensive use in salt water heat-exchangers and in distillation-type desalination plants.The results obtained, particularly with respect to the tred of anodic polarisation with corrosion time, showed the suitability of electrochemical methods for providing data for the comparative assessment of the corrosion behaviour of copper alloys in sea-water environments, In spite of the non-chemIcal character of passivity for such alloys.