Corrosion Of Cu Research Articles

Corrosion of Cu under Highly Corrosive Environments

Cu corrosion in mixed flowing gases (MFG) has been widely studied. However, most of these studies have been carried out using conditions which were designed for accelerated tests simulating North America and Western Europe. More and more equipment are being deployed to emerging markets such as Asia Pacific and China, Eastern Europe, and the Middle East, where they are subjected to much more corrosive environments than those typically seen in North America and Western Europe. There is a need to understand the corrosive conditions in the emerging markets and come up with an accelerated test for products to be deployed in those conditions. In this work, we investigated the corrosion products on test Cu coupons exposed to harsh conditions by a combination of several analytical techniques. This work allowed us to establish a procedure for quantifying corrosion products and led to insights about corrosion mechanisms for copper in highly corrosive environments. Results showed that the corrosion of copper in the highly corrosive MFG testing condition (containing , , , and ) leads mainly to the formation of copper sulfide at the exposed surface, with the presence of a thin, buried cuprous oxide layer sandwiched between and copper substrate. The thickness of the corrosion products increases linearly with the exposure time.

Corrosion of Cu and Steels Exposed to Simulating Accelerated Atmospheric Corrosion Conditions

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A review of the effects of benzotriazole on the corrosion of copper and copper alloys in clean and polluted environments

A continuing challenge in materials design is the achievement of high operational efficiency through improvements in performance criterion, particularly its service life-time characteristics. Benzotriazole (BTAH) has now been in use for many years for the protection of copper and copper alloys against various forms of corrosion. In this review, the chemistry of BTAH and theories regarding its mode of action are summarized. Also, a survey of the reported work in both clean and polluted environments is documented. More interestingly, the adverse effect of BTAH on the corrosion of Cu and Cu alloys in sulfide polluted environments is introduced.

Long-term stability of Cu/Pd nanoparticles and their feasibility for electroless copper deposition

Poly-vinylpyrrodione (PVP) protected Cu/Pd nanoparticles synthesized with citric complexing agent were developed as activator for electroless copper deposition in printed-circuit boards (PCBs) industry. Cu/Pd nanoparticles in different molar ratio were employed in electroless copper deposition and found that the catalytic activity was influenced not only by the amount of Pd content or particle size but also by the surface protected PVP layer. From the time-resolved electroless copper deposition, we suggested that the catalytic efficiency should be evaluated by both initial activity and the structure of deposited copper film. As a result, the Cu/Pd nanoparticles of molar ratio = 1/2 was found to have best catalytic activity which was comparable to traditional Pd/Sn or pure Pd activator. In regard to the most concerned stability issue of Cu-content system, a surprising slow galvanic corrosion of Cu was found when Cu/Pd nanoparticles were exposed to the open air. Besides, slightly oxidation of Pd was found after air-exposure. Surprisingly, these Cu/Pd colloids maintain part of activity and well suspension even after 6-month exposure, suggesting well long-term stability as activator. In short, Cu/Pd nanoparticles synthesized with citric complexing agent with high catalytic activity and long-term stability was a promising activator for electroless copper deposition.

Electrochemical studies of pitting corrosion of Cu–Fe alloy in sodium chloride solutions

The electrochemical studies of pitting corrosion of Cu–Fe alloy (70% Cu–30% Fe) were carried out in sodium chloride solutions. The techiniques of measurements were: open-circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy. The effect of different concentrations of the inorganic additives (WO 4 2−, PO 4 3−, NO 2 −, B 4O 7 2− and CrO 4 2−) on the pitting corrosion of the alloy in 0.5 M NaCl was also studied. It was found that the alloy underwent pitting corrosion in sodium chloride solution at definite pitting potential depending on the concentration of NaCl according to the relation: E pit = a 1 − b 1 log C C l − . The investigated inorganic additives had inhibiting effect on the pitting corrosion of the alloy in 0.5 M NaCl and their efficiency decreases according to the order WO 4 2− > PO 4 3− > NO 2 − > B 4O 7 2− > CrO 4 2−.

Study of Mixed Flowing Gas Exposure of Copper

This paper describes the results of copper coupons exposed to a class III mixed flowing gas environment (MFG) following the guidelines given by the Battelle Laboratory and the International Electrotechnical Commission for environmental testing. Corrosion products were studied in detail using scanning electron microscope, energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), focused ion beam (FIB), secondary ion mass spectroscopy (SIMS), and transmission electron microscope. The weight gain measured after each exposure was compared with the weight gain calculated from the cathodic reduction of the corrosion layers and cross sectioning using an FIB. The result shows a relatively good correlation between the measured and the calculated experimental values of weight gain. As expected, within the first week, the different corrosion layers thickened until they formed a thick layer that became the determining step for further growth. After several days of exposure the Cu coupons developed a complex multilayered structure consisting of cuprous oxide , cupric oxide (CuO), copper sulfide , covellite (CuS), and evidence of antlerite . No Cl-containing corrosion products were identified using XRD. However, EDS and SIMS analysis showed that Cl was distributed throughout the corrosion products, indicating that although Cl is inside the corrosion products, it is not part of the crystalline structure. Also, this suggests that Cl plays an important role in accelerating the corrosion of Cu during exposure to the MFG class III test.

Incorporation of Cu Passivators in Post-CMP Cleaners

Simple first generation Cu post-CMP cleaners, such as oxalic acid solutions, promote corrosion of Cu due to removal of BTA and dissolution of cuperous oxide (Cu2O). The use of simple organic acid solutions imposed a short staging time before processing wafers to the next level due to corrosion of the exposed Cu. In some cases, a maximum holding time of less than one hour was needed to reduce device yield loss and reliability issues resulting from Cu corrsion. A way to significantly increase the post-clean wafer holding time was by incorporating a Cu passivator into the post-CMP cleaner. Four commonly used Cu passivators were evaluated in a commercially available, alkaline, post-CMP cleaner. Several unanticipated properties were observed when using 1,2,4-triazole, which will be discussed.

Synthesis and corrosion protection study of poly( o-ethylaniline) coatings on copper

Poly( o-ethylaniline) coatings were synthesized on copper (Cu) by electrochemical polymerization of o-ethylaniline in an aqueous salicylate solution by using cyclic voltammetry. The characterization of these coatings was carried out by cyclic voltammetry, UV–visible absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results of these characterizations indicate that the aqueous salicylate solution is a suitable medium for the electrochemical polymerization of o-ethylaniline to generate strongly adherent and smooth poly( o-ethylaniline) coatings on Cu substrates. The performance of poly( o-ethylaniline) as protective coating against corrosion of Cu in aqueous 3% NaCl was assessed by the potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The results of these studies demonstrate that the poly( o-ethylaniline) coating has ability to protect the Cu against corrosion. The corrosion potential was about 0.078 V versus SCE more positive in aqueous 3% NaCl for the poly( o-ethylaniline) coated Cu (∼ 15 μm thick) than that of uncoated Cu and reduces the corrosion rate of Cu almost by a factor of 70.

Pitting corrosion of Cu–Zr metallic glasses in hydrochloric acid solutions

Abstract The corrosion behavior of Cu x Zr 100− x ( x = 40, 50 and 60 at.%) metallic glasses prepared by rapid quenching were investigated by means of electrochemical polarization measurements and immersion tests in 0.01 and 0.1 mol/L HCl solutions, respectively. The influence of the alloy composition on morphological and compositional characteristics of pit regions was discussed in detail. All the investigated Cu–Zr metallic glasses are susceptible to pitting corrosion due to the adsorption of the Cl − ions. The pit morphology is strongly dependent on the Cu concentration of the alloy. A more severe corrosion on the wheel sides compared with the air sides demonstrates that the surface characteristics play an important role in influencing the corrosion resistance of the glassy alloys.

Corrosion protective poly( o-ethoxyaniline) coatings on copper

Poly( o-ethoxyaniline) (POEA) coatings were synthesized on copper (Cu) by electrochemical polymerization of o-ethoxyaniline in aqueous salicylate solution by using cyclic voltammetry. These coatings were characterized by cyclic voltammetry, UV–vis absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The performance of POEA as protective coating against corrosion of Cu in aqueous 3% NaCl was assessed by the potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The results of the potentiodynamic polarization and EIS studies demonstrate that the POEA coating has ability to protect the Cu against corrosion. The corrosion potential was about 0.330 V versus SCE more positive in aqueous 3% NaCl for the POEA coated Cu than that of uncoated Cu and reduces the corrosion rate of Cu almost by a factor of 140.

Inhibiting effect of 2-mercaptobenzimidazole on the corrosion of Cu–30Ni alloy in aerated 3% NaCl in presence of ammonia

The inhibiting effect of 2-mercaptobenzimidazole (MBI) against Cu–30Ni alloy corrosion in aerated 3% NaCl polluted by ammonia, has been developed. Potentiodynamic and electrochemical impedance spectroscopy (EIS) measurements have been applied to determine the corrosion rate. scanning electron microscopy (SEM) studied surface morphology has been used to characterise electrode surface. The obtained results indicate that MBI acts as a good mixed-type inhibitor retarding the anodic and cathodic reactions. An increase of MBI concentration leads to a decrease of corrosion rate and inhibition efficiency increase.

Electrodeposition of Cu onto Pt in presence of egg ovalbumin

In the present paper, the effect of egg ovalbumin (OVA) on the electrodeposition of Cu and on the underpotential deposition (UPD) and overpotential deposition (OPD) behaviour of Cu on polycrystalline Pt electrodes is studied. The interfacial behaviour of OVA was studied at a polycrystalline Pt electrode, using cyclic voltammetry (CV) below (25°C) and above (80°C) the OVA denaturation temperature. Ovalbumin was found to adsorb strongly at the Pt surface. As the temperature was increased above the denaturation value, the surface charge density for OVA adsorption also increased, owing to conformational unfolding. Above the denaturation temperature, the surface charge density continued to increase, suggesting multilayer adsorption. Cyclic voltammetry measurements during Cu electroplating from an acidic chloride bath in the presence of OVA at 25°C highlighted a remarkable electrodeposition and stripping inhibition. This effect was not observed at 80°C. Potentiodynamic measurements in the Cu plating bath highlight a strong OVA adsorption in a well defined potential interval. In situ surface enhanced Raman spectra were measured both during electrodeposition and corrosion of Cu in the Cu plating bath. Potential dependent changes of spectral pattern have been found, which can be interpreted in terms of conformational changes of adsorbed OVA. The study was complemented by morphological and optical characterisation of electrodeposited Cu by scanning electron microscopy and spectral reflectivity measurements. Scanning electron microscopy observations reveal notable changes of morphology, possibly related to the assembly of adsorbed protein at the electrode and to the modification of the electrodic charge transfer process. Finally, comparative spectral reflectivity measurements showed that the addition of OVA brings about changes of the electronic structure of the Cu film.

On the mitigation of erosion–corrosion of copper by a drag-reducing cationic surfactant in turbulent flow conditions using a rotating cage

Erosion–corrosion is a complex materials degradation mechanism involving the combined effects of mechanical erosion and electrochemical corrosion. It is known to be induced by high shear stresses in strong flows. One way to mitigate this phenomenon is to use additives reducing the turbulent Reynolds stresses. Oleyltrimethyl ammonium cationic surfactant and sodium salicylate as counter-ion known to form thread-like micelles behaving as drag reducers were tested in this work and successfully imaged by using AFM technique. A shear stress mapping in the rotating cage using an electrochemical method was implemented in the absence and in the presence of surfactant, showing drag reduction amounts up to 65%. In a second step, erosion corrosion of Cu in Na 2SO 4 0.1 M in the presence of small amounts of NaCl (1 mM) was investigated on Cu microelectrodes located at different positions on plastic coupons in the cage. The surfactant effect was found to be beneficial by preventing the removal of the pre-existing oxide films, otherwise observed in the absence of surfactant. Tests performed with benzotriazole known as a good corrosion inhibitor for Cu, could not prevent either the breaking of the oxide film in strong flow conditions.

The corrosion behavior of Cu–Al and Cu–Al–Be shape-memory alloys in 0.5 M H 2SO 4 solution

The corrosion behavior of Cu–Al and Cu–Al–Be (0.55–1.0 wt%) shape-memory alloys in 0.5 M H 2SO 4 solution at 25 °C was studied by means of anodic polarization, cyclic voltammetry, and alternative current impedance measurements. The results of anodic polarization test show that anodic dissolution rates of alloys decreased slightly with increasing the concentrations of aluminum or beryllium. Severe intergranular corrosion of Cu–Al alloy was observed after alternative current impedance measurement performed at the anodic potential of 0.6 V. However, the addition of a small amount of beryllium was effective to prevent the intergranular corrosion. The effect of beryllium addition on the prevention of intergranular corrosion is possibly attributed to the diffusion of beryllium atoms into grain boundaries, which in turn deactivates the grain boundaries.

Peptidic compound as corrosion inhibitor for brass in nitric acid solution

The study of Boc–Phe–Met–OCH 3 as corrosion inhibitor for 60Cu–40Zn in nitric acid solution was performed through weight loss and electrochemical polarisation measurements. The corrosion rate is highly reduced in the inhibited nitric acid. The inhibition efficiency E (%) reached a maximum value of 100% for Boc–Phe–Met–OCH 3. Polarisation measurements indicated that Boc–Phe–Met–OCH 3 acted as cathodic inhibitors without changing the mechanism of the hydrogen evolution reaction. The results showed that the inhibition occurred via chemisorption of the inhibitor molecules on the corroding metal following Frumkin’s isotherm. The effect of the temperature in the range 303–353 K on the corrosion of Cu–Zn alloy in 0.5 M nitric acid with and without addition of Boc–Phe–Met–OCH 3 has been studied. The associated activation energy has been determined.

Effect of β martensite transformation on dealuminification behavior of Cu–9Al–2Mn alloy in a marine environment

Duplex type aluminum bronzes usually exhibit a structure consisting of α and the interconnecting eutectoid matrix of α and γ particles. These γ particles are highly anodic to the α particles. Usually the β phase is retained because it is less anodic to α particles than the γ phase. In our previous study, observation of the development of dealuminification corrosion of Cu–9Al–2Mn alloy in an early stage was first carried out by in situ scanning tunneling microscope (STM). It has been indicated that the existence of the β phase has a negative effect on dealuminification corrosion of aluminum bronzes, which occurs preferentially on the β phase. In order to determine the influence of β phase transformation in Cu–Al–Mn alloys on their dealuminification micro-mechanism, the change in the microstructure before and after dealuminification corrosion of Cu–9Al–2Mn alloy was investigated in the present work. Results indicate that dealuminification corrosion of Cu–9Al–2Mn alloy is associated with martensite transformation of metastable β1 phase and occurs within the β′1 martensite plates, in which there is a large amount of stacking faults. Micro-pits and fine corrosion products were also observed by TEM. The reason why β1' martensite plates suffered a preferential dealuminification corrosion is martensite transformation of β-Cu3Al phase and the higher density of stacking faults in β1' martensite plates.

Biocorrosion of Copper in Potable Water

Copper (Cu) is widely accepted as a durable, corrosion‐resistant conduit for potable water. However, over the past decade, the corrosion of Cu in potable waters has been critically assessed, triggered by tighter regulatory standards for potable water and wastewater, higher consumer expectations, and the recognition of a possible microbiological role in corrosion failures. At least two unusual types of pitting corrosion in hot and cold water systems and several anomalous cases of excessive Cu corrosion by‐product release (“blue water”) have features consistent with microbially influenced corrosion (MIC). Cu corrosion by‐product release has traditionally been considered controlled by inorganic water chemistry. However, recent work has demonstrated that MIC can potentially produce excessive Cu concentrations under optimized water treatment conditions. This article discusses recent developments in understanding the influence of biofilms (microorganisms attached to and growing on a surface) on Cu corrosion.

Quality of roof runoff for groundwater infiltration

The assumption that roof runoff can be considered as non-polluted stormwater that can be discharged directly into natural water bodies without impairing their quality and use was examined in a field study. Concentrations of major ions; total C, N, and P; heavy metals (Cu, Zn, Pb, Cd, Cr, Mn, Fe) and pesticides (triazines, acetamides, phenoxy acids) were measured in runoff from an inclined tile roof, an inclined polyester roof and a flat gravel roof. Runoff from the first two roofs showed initially very high concentrations declining rapidly to lower constant levels. This first-flush effect was modelled using a first-order rate law (wash-off function). For most constituents, concentrations were in the range of the wet deposition after the first few mm runoff depth and total loads in the runoff corresponded approximately to the total (dry and wet) atmospheric deposition load. The flat gravel roof depicted a different behaviour. Rainwater was first retained before it overflowed. Consequently gravel will be weathered and most pollutants were partially retained in the gravel layer. However, corrosion of Cu in drains (rate about 5 g m −2 y −1) produced such high Cu concentrations that direct disposal of runoff is questionable.

An XPS and AES study of the free corrosion of Cu-, Ni- and Zn-based alloys in synthetic sweat

This paper deals with the investigations into the behaviour during free corrosion of Cu/Zn/Ni, Cu/Ni/Zn and Ni/Cu alloys in a synthetic sweat medium by means of surface analyses. For the three alloys studied, our experimental results indicate the presence of a corrosion layer, the thickness of which increases with the increase of the copper content of the alloy. The corrosion layers are composed of Cu- and Ni-based compounds. For the alloys with a high Cu content, the latter is mainly composed of copper (I) oxide in which chloride anions are included. For the alloys with a high Ni content, Cu 2 (OH) 3Cl and Ni-compounds like Ni (OH) 2 and NiO are detected in the corrosion layer.

Effect of chloride concentration range on the corrosion resistance of Cu–xNi alloys

The anodic behaviour of Cu–xNi alloys and Cu and Ni metals was studied in slightly alkaline solutions containing Cl−-ions in the concentration range from 0.01 to 2.0moldm−3. The morphology and composition of the surface films formed by anodic polarization were analysed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). On the basis of quasi-potentiodynamic polarization data, Ec against cNaCl diagrams were constructed, where Ec is the critical pitting potential. These diagrams allow the determination of areas where the materials are susceptible to localized pitting attack. A critical chloride concentration (ccrit) exists below which the resistance to localized corrosion increases with decreasing nickel content and above which it increases with increasing nickel content. This effect is connected with the change in the corrosion resistance observed for the pure metal constituents, i.e., copper and nickel as a function of chloride concentration. The kinetic parameters of pitting corrosion of Cu–xNi alloys reflect the specific properties of both elements and suggest that an increase in Ni content above 40% would not have a significant effect on the corrosion resistance of Cu–xNi alloys.