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The influence of sulfur on the hot compression properties of C71500 cupronickel alloy and the mechanism of thermo mechanical effect are studied for the first time. The composition of sulfide inclusions and its damage mechanism to properties were also studied. The effect of sulfur content on the dynamic recrystallization activation energy and the properties of the alloy was deduced and explained systematically. The relationship between the dynamic recrystallization activation energy and sulfur content was obtained, and a energy dissipation model was established based on the dynamic material model. The Prasad’s instability criterion was used to predict the unstable region in the processing chart. The effect of sulfur on the processing parameters selection was compared under different strain conditions, which could provide the ideal processing technology for the thermal deformation of C71500 alloy with various sulfur content.

Spray coating formation of stearic and octadecylphosphonic acid films for corrosion protection of cupronickel alloy was studied in this work as a more practical alternative to widely studied dip-coating method. Protective properties of organic films formed under various experimental conditions were examined by electrochemical studies in 3% NaCl solution as a corrosive medium. Polarization resistance measurements as well as electro­chemical impedance spectroscopy were employed to follow in time the corrosion behaviour of cupronickel alloy modified by studied organic acids. It was found that among examined experimental parameters, time elapsed between two sprays and number of sprays have the strongest influence on the film stability and its protective properties. This study confirmed that it is possible to form by spray coating the films of stearic and octadecyl­phosphonic acid with protective properties that resemble to those of the films prepared by dip-coating method. Differences in corrosion behaviour of samples protected with stearic and octadecyl­phosphonic acid were attributed to difference in the bond strength between substrate and each organic acid. Studied samples were also examined by the scanning electron microscopy. Fourier transformed infrared spectroscopy studies showed that crystalline structure dominates in studied films, while contact angle measure­ments confirmed that modified cupronickel alloy surface exhibits hydrophobic properties.

Debinding is one of the most critical processes in metal paste injection 3D printing technology (MPI). In order to design the optimal debinding parameters, the debinding temperature, debinding time and heating rate were discussed from the perspective of dynamics. The results showed that there was a peak in liquid phase mass transfer during debinding, exhibiting the characteristics of migration with debinding temperatures. For gas phase mass transfer, when the temperature was 300 °C, the thermal debinding diffusion coefficient was the largest (9.7 × 10−5 cm2 s−1) and the corresponding debinding time was 3.5 h. By analyzing the activation energy of the debinding reaction, when the heating rate was 10 °C min−1, the activation energy required for the thermal debinding reaction was the smallest. Combined with the sintering process, the interwoven structural parts of the copper and cupronickel components were finally obtained. The average hardness of the polymetallic parts was 78.8 HV, and the density was 8.1 g cm−3.

Ultrasonic spot welding (USW) is a solid-state joining process which is preferably adopted in the joining of lithium-ion battery tabs for hybrid electric vehicles. It has several benefits o...

Recycling of the cupronickel alloy scraps not only solves environmental related issues but also realizes the extraction of valuable metals and saves consumption of primary ore resources. Oxidative dissolution is a critical step for the recycling of valuable metal from the alloy scraps. In order to improve the dissolution kinetics and efficiency, a novel integrated electrochemical dissolution strategy for the sustainable recycling of the cupronickel alloy scraps was first developed, where the in-situ electro-generated reactive oxygen species (ROS) were employed as the indirect oxidative mediator. Much higher dissolved concentration of Ni, Zn, and Cu was reached by the present integrated strategy than that of the direct anodic dissolution process, which is attributed to the in-situ produced oxidative H2O2 and ·OH via oxygen reduction reaction and electro-Fenton-like reaction, respectively. Moreover, the large quantity of ROS can be electro-generated, thus achieving high dissolved concentration, under the optimum condition with the preset potential of 0.3 V (vs. Ag/AgCl) or current density of 2.54 mA/cm2, respectively. This novel synergistic strategy may serve as a promising and cost-effective technique for the alloy scraps recycle and valuable metal extraction.

An environmentally benign and facile bilayer coating comprised of graphene oxide (GO) and acrylic polymer is fabricated over cupronickel sample using electrophoretic deposition followed by dip coating. The infrared, Raman, and field emission scanning electron microscopy (FESEM) studies of the bilayer coating confirm the noncovalent functionalization of GO through H-bonding with acrylic polymer, reduction in local defects in GO structure, and distorted spherical void peripheries of polymer coating, respectively. The FESEM cross-sectional analysis showed that the coating thickness is 5–6 µm. The bilayer-coated sample showed a three- to fourfold increase in the corrosion resistance, as compared to GO-alone-coated sample in 3.5% (w/v) NaCl electrolyte, which is attributed to the reduction in the local defects in GO coating and the galvanic coupling between the GO and sample surface. The GO sheets make the diffusion pathway of corrosive media more tortuous for corrosive ions to reach the metal surface. The lower anodic current density observed with the new bilayer coating after 30 days of exposure confirms the active corrosion protection. The coating was intact and stable after 30 days of exposure in chloride medium with a water uptake of about 32.7%.

The corrosion inhibition of cupronickel alloy in 5% hydrochloric acid (HCl) was investigated in the absence and presence of diethylenetriamine (DETA) and ethylenediamine (EDA) as organic corrosion inhibitors. The effects of inhibitor concentration and temperature were investigated using mass loss method. The results obtained show that EDA act as an anticorrosion material for cupronickel alloy in hydrochloric acid with a maximum performance of 66.7%, while DETA was a poor inhibitor with maximum efficiency of 34.7%. The inhibition performance was found to increase with increase in inhibitor concentration and decrease with increase in temperature. The adsorption of both inhibitors on surface of metal was found to obey Freundlich isotherm. The values of the free energy of adsorption were below − 20 kJ/mol that is indicative of physisorption (physical adsorption). The proposed mechanism of the inhibition process suggests an adsorption of amine groups on metal surface. Mathematical models were also suggested to correlate the dissolution rate data as a function of temperature and inhibitor concentration. High correlation coefficients were obtained between experimental and predicted data. The mean value of residual between the experimental and predicted data was 0.457.

Morphology, dimensions, crystalline structure and compositions of nanomaterials are very critical in determining their unique characteristics. Here we report how the reducing agent concentration affects the surface morphology of copper nanowires and establish the optimized reaction conditions to synthesize high aspect ratio nanowires with a smooth surface. Also, reported is the magnetic field assisted technique to control the orientational and positional ordering of cupronickel nanowires (Cu/Ni NWs) on a large-scale area. A combination of magnetic field, surface derivatization and photolithographic techniques allowed self-assembly of Cu/Ni NWs into channels. The channel resistance as a function of the applied magnetic field during fabrication shows an anomalous decrease owing to the positional end-to-end alignment of NWs. Magnetic field and areal NW density dependence of NW sheet resistance in channels is presented and analyzed using scaling theoretical models.

Changes of the microstructure of the interface in intensification of the explosion welding conditions for the copper – cupronickel alloy, simulating the copper–copper homogeneous pair are i...

The deterioration of metals under the influence of corrosion is a costly problem faced by many industries. Therefore, particle-reinforced composite coatings are being developed in different technological fields with high demands for corrosion resistance. This work studies the effects of nanoplatelet reinforcement on the durability, corrosion resistance, and mechanical properties of copper-nickel coatings. A 90 : 10 Cu-Ni alloy was coelectrodeposited with nanoplatelets of montmorillonite (Mt) embedded into the metallic matrix from electrolytic baths containing 0.05, 0.10, and 0.15% Mt. X-ray diffraction of the coatings indicated no disruption of the crystal structure with addition of the nanoplatelets into the alloy. The mechanical properties of the coatings improved with a 17% increase in hardness and an 85% increase in shear adhesion strength with nanoplatelet incorporation. The measured polarization resistance increased from 11.77 kΩ·cm2 for pure Cu-Ni to 33.28 kΩ·cm2 for the Cu-Ni-0.15% Mt coating after soaking in a simulated seawater environment for 30 days. The incorporation of montmorillonite also stabilized the corrosion potential during the immersion study and increased resistance to corrosion.

Citrus paradisi and Cymbopogon distillates were admixed in ratio 1:1 and assessed for their inhibition effect on Cu-Ni cupronickel alloy in 0.25 M H2SO4–3.5% NaCl electrolyte. Results revealed the distillates effectively inhibited the Cu-Ni alloy at 2–5% CPC concentrations. The degradation rate of Cu-Ni alloy without distillate is 0.373 mm/y whereas at 1% concentration, the degradation rate decreased to 0.140 mm/y (1.37 × 10−5 A/cm2) corresponding to inhibition efficiency of 62.46%. At 2–5% concentration, inhibition efficiency ranged between 80.47 and 95.58%. The distillate displayed mixed-type inhibition performance coupled with significant suppression of cathodic reduction reactions. Thermodynamic calculations showed the distillates adsorbed unto the Cu-Ni alloy by chemisorption according to Langmuir and Freundlich adsorption isotherms (correlation coefficients above 0.8). Gibbs free energy indicate increase lateral attraction effect among the distillate molecules with respect to #concentration. Open circuit potential curves showed the distillates increased the thermodynamic instability of Cu despite effective inhibition performance.

A simple method of electrodeposition of a new class of materials – W-Ni-Cu alloys – has been proposed. The mean tungsten content was higher than 20 at.% which is a substantial increase compared to other reported in the literature values: 5–10 at.%. The major influencing factors of the plating process were identified and examined. This allowed us to settle the conditions for deposition of various W-Ni-Cu materials. These ternary alloys can be deposited from aqueous citrate solutions by employing the appropriate ratio of concentrations of W, Ni and Cu in the bath. The galvanic bath used for the electroplating is environmentally friendly and of low toxicity. The deposits are metallic, uniform, shiny and highly adhesive to various substrates. The layers colour, depending on copper percentage, can vary from dark silvery to bright silver-orange. Also, various mechanical properties of the deposits can be obtained by properly adjusting bath composition and therefore layer stoichiometry. The internal structure of the deposits was investigated and it was found that the size of structurally organized regions was circa 3–5 nm. The obtained material consists of two phases: a) nanocrystaline of a structure similar to cupronickel with decreased percentage of W and b) fully amorphous phase/matrix containing higher, than the mean value, percentage of W. The galvanic W-Ni-Cu layers did not exhibit preferred orientation in the [111] direction which is typical for the binary tungsten – iron-group-metal electrodeposited alloys.

Diffusion bonding is one of the metal joining process to join same and well as dissimilar metals. In this project stainless steel and copper plates were joined together with the interlayer of cupronickel sheet. The temperature was maintained in the range of 800 - 850°C. At the same time of heating compression load also acting on the specimensupto 5 MPa. To prevent the oxidation process vacuum of 10-4 Torr was maintained. The experiment was conducted for 60 Min. distinct diffusion zones were formed in the joined area of the specimens. The experiments were conducted with different temperatures and pressure. The shear strength of the specimens was tested and at 825°C have maximum shear strength of 8.47KN.

The performance of Benzotriazole (BTA) as a stress corrosion cracking (SCC) inhibitor is investigated for Cu-30Zn and Cu-27Ni alloys in Mattsson’s solution using electrochemical techniques and slow strain rate test (SSRT). With the addition of BTA, the polarization resistance increases for both alloys. Electrochemical impedance measurements show that BTA can form a protective film on the surface of the Cu-27Ni alloy and shifts the corrosion potential to nobler states. BTA also improves the corrosion resistance of the Cu-30Zn alloy by controlling the cathodic reaction rate and charge transfer resistance. SSRT results reveal that the presence of BTA decreases the susceptibility to SCC for both alloys; this improvement is more significant for Cu-27Ni alloy. Fractographic analysis after SSRT confirms that crack propagation regime is controlled by the BTA concentration. For Cu-27Ni alloy, fracture type changes from intergranular brittle to ductile as the protectiveness of BTA increases. Besides, BTA recovers the ductility by decreasing crack tip dissolution and growth as fewer cracks are observed around the necked area of fractured Cu-30Zn alloy tensile sample.

Advances in flexible optoelectronic devices have led to increasing need for developing high performance, low cost, and flexible transparent conducting electrodes. Copper-based electrodes have been unattainable due to the relatively thermal instability and poor oxidation resistance. Herein, we present oxidation-resistive CuNi nanomesh electrodes that exhibit a low sheet resistance of ∼7.5 Ω/□ and a high optical transmittance of ∼81% at 550 nm. Further, high long-term stability against the effects of oxidation, heat, and chemicals is exhibited by the CuNi nanomesh, in comparison with the behavior of a pure Cu nanomesh sample.

Herein, we developed a straightforward and effective method to prepare epoxy coating for the early stage corrosion-detection of copper alloy. A selective “turn-on” chemosensor derived from rhodamine B for Cu(II), 3′,6′-Bis(diethylamino)-2-[[(2-hydroxyphenyl)methylene]amino]spiro[1H-isoindole-1,9′-[9H]xanthen]-3(2H)-one (RHS), was obtained via a two-step synthesis of acylation and schiff-base reaction. Both the colorimetric and fluorescent signals of the typical 0.5 wt% sensor-doped coating was observed, which showed that the area prior to corrosion was no significant damage. The concentration of RHS could be reduced to 0.14 wt%, after the zinc-based metal–organic framework (MOF) particle, ZIF-8, applied as a nanocontainer in this coating, and the detection sensitivity was better than the coating with bare RHS. This nondestructive strategy successfully realized early-stage corrosion detection for cupronickel in epoxy coating, which could be potentially used in the corrosion detections for copper alloys.

The research of platinum metal recovery from compound solutions including process ones with high salt content in non-ferrous and other metals is given. Effective conditions for platinum metal sorption recovery from sulphate cupronickel solutions by nitrating and anodizing methods are stated. The level of platinum family recovery is 95-99%.

Self-assembly of organic molecules onto metallic surfaces is an efficient way to modify surface properties of metallic materials. The aim of this paper was to examine the possibility of improving the corrosion stability of copper nickel alloy in chloride environment by self-assembled films of palmitic and stearic acid. Electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to determine the protective properties of the fatty acids films. Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and contact angle (CA)measurements were used to evaluate structural properties of the surface layers. It was found that even a small difference in a fatty acid chain length might have a strong effect on layer stability in aqueous medium.

Cupronickel is known as an alloy. It is composed of mainly copper. Cupronickels also include 10–30% nickels. It is used around us. We had very limited information about surface of cupronickels coins. In this study, we investigated surface of a cupronickel coin by scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDS) and Fourier Transformation Infra Red (FTIR) spectroscopy. We found specific white regions on the surface. We could detect chlorine on the surface of cupronickel coins.

A theoretical model of infiltration kinetics based on the Darcy's law which was evaluated by W − Lambert function has been established for Cu-Ni-Mn alloy (grade MNMts 60-20-20) during melt infiltration into Cr3C2 porous skeletons with different morphology. It is shown, that theoretical calculations are in good correlation with experimental data obtained by pressureless infiltration of carbide preforms with open porosity 20-40 vol. % at 1200 °C. Calculations shows that infiltration height dependence on the average size of carbide particles is described by curves with a maximum which corresponds to~ 60 μm for specified system with carbide skeleton porosity of 40 vol. %. Key words: chromium carbide, manganese cupronickel, cermet, infiltration, Lambert W-function., Для процесу просочування пористих каркасів із Cr3C2 із різною морфологією сплавом Cu-Ni-Mn (марка МНМц 60-20-20) була розроблена теоретична модель кінетики просочування на основі закону Дарсі із використанням W- функції Ламберта. Показано, що теоретичні розрахунки з достатньо високою точністю описують експериментальні дані, які були отримані при просочуванні у вакуумі карбідних каркасів із відкритою пористістю 20-40 об.% при 1200 °С. Розрахунки показують, що залежність глибини просоченого шару від середнього розміру карбідних частинок описується кривою з максимумом, який для вказаної системи припадає на ~60 мкм при пористості карбідного каркасу 40 об. %.

The paper describes an experimental study concerning the influence of major environmental parameters (temperature, chloride, carbon dioxide, and oxygen) on the corrosion behavior of 90/10 Cu–Ni alloys widely used for heat-transfer tubes. Electrochemical techniques have been used to investigate the corrosion behavior of 90/10 Cu–Ni alloys in aerated 3.5% NaCl solutions, at temperatures of 25, 50, and 80°C with and without the injection of carbon dioxide. The results have revealed increases in chloride corrosion rates of the 90/10 Cu–Ni alloy with temperature and decreases with CO2 presence. Tests performed in aerated chloride–CO2 solutions have shown higher corrosion rates relative to those conducted in deaerated chloride solutions saturated with CO2 species. The surface morphology of polarized specimens in chloride solutions with and without CO2 presence has shown a susceptibility to pitting attack. Pit characteristics have been found to be highly influenced by CO2 presence.

Copper-nickel alloys are extensively used in marine applications and in desalination plants (Sherif et al. in Colloid J Interface Sci 311:144, 2007; Sherif and Park in J Electrochim Acta 51:4665, 2006) because of their good electrical and thermal conductivities, mechanical properties, corrosion resistance, and ease of fabrication of the equipment (Revie in Uhlig’s corrosion handbook. Wiley, New York, p. 729, 2000).

The aim of this work was to form protective and durable films of octadecylphosphonic acid on the surface of CuNi alloy. In order to achieve this goal several parameters of the film preparation procedure were examined: temperature and duration of adsorption as well as the drying temperature. It was found that these parameters had significant impact on the corrosion protection efficiency and durability. The best corrosion protection was obtained when both adsorption and drying were conducted at elevated temperatures. The maximum protection efficiency was 96% for the first and 82% for the 14th day of exposure to corrosive medium.

The fabrication of uniformly interconnected cupronickel (CuNi) micromesh films on glass and polymer substrates with seamless junctions has been achieved using a simple transfer printing method. When used as a transparent heater, these CuNi micromesh films exhibited an effective and rapid heating performance at low input voltages (below DC 9 V) that can be attributed to the creation of a high quality network over the whole surface area that offers a relatively high transmittance, strong adhesion to its substrate and good mechanical flexibility. A high thermal stability and reliability was also observed relative to a pure Cu micromesh film. Transparent heaters based on CuNi micromesh are therefore considered suitable for providing anti-fogging or de-icing in optics and optoelectronic devices, as well as for wearable heating systems.

The material used to produce one baht coin in the Royal Thai Mint has been changed from cupronickel (75% Cu and 25% Ni) to nickel-electroplated steel, not only for economic reasons but also for the durable properties of the latter. As a result, the higher hardness value of the new material (110 HV30 versus 80 HV10) combined with the high accuracy requirements of the coin detail have reduced the durability and lifetime of coining tools. The number of coins produced by a single coining tool was reduced from approximately 300,000 to only 40,000 coins. However, the tool life can be increased if proper selections of tool material and hard thin film coating technique are made. Two types of tool material were selected: cold working tool steel, 0.97% C and warm working tool steel, 0.5% C. CrN, TiN and TiCN coatings were examined using physical vapour deposition (PVD). It was determined that the type of tool material, the type of coating material, the coating temperature and the coating thickness influenced the lifetime of a coining tool. For the conditions studied, a 3-µm-thick TiN coat on warm working tool steel produced under a coating temperature of 400 °C provided the maximum tool life up to 1.22 million strokes.

The application performances of TA2 titanium\S44660 super ferrite stainless steel\B30 cupronickel, which are widely used in power plant, were researched using electrochemical test and mechanical test. The results show that corrosion resistance of B30 is significantly lower than TA2 and S44660. Besides, corrosion resistance of S44660 is superior to TA2. Yield strength and tensile strength of S44660 is higher than TA2 and B30. When considering thickness of cooling tubes, flow rate of cooling water and clean coefficient, the thermal conductivity of three materials have little differences. The shock resistance of S44660 is better than TA2 and B30. S44660 contains a small amount of Ni, which improves greatly the anti-cracking ability of the base metal and welding bead.

Cupronickel was used as the electrode material to fabricate microstructures on polycrystalline diamond by electrical discharge machining (EDM). The electrodes were shaped into tiny rotary wheels driven by the flow of EDM fluid. Results showed that material removal rate was improved by a factor of five compared to conventional electrode materials. Raman spectroscopy and energy dispersive X-ray spectroscopy indicated that graphitization of diamond and diffusion-based chemical reactions between nickel and diamond dominated the EDM process. Effects of electrode rotation rate and discharge energy on the EDM characteristics were clarified. High form accuracy (∼0.5 μm/1 mm) and low surface roughness (∼0.1 μm Ra) were obtained.

Corrosion fatigue performance of two copper alloys (admiralty brass and cupronickel 90/10) is investigated by conducting fatigue tests in artificial seawater. Two different experimental setups are developed and used: immersed rotating beam bending of round wires and immersed flexural cycling of rectangular plates. For the second setup, two sets of specimens are used: as-manufactured and after 1-year exposure to natural seawater in North Atlantic. In addition, the fatigue performance is compared between the dry and immersed tests. It is observed that the fatigue life of copper alloys in seawater environment depends on their composition and manufacturing parameters. Immersion in seawater does not affect low-cycle fatigue, however, high-cycle fatigue behavior shows significant differences. It is also observed that one-year preliminary exposure to natural seawater (stress-free corrosion) results in up to three times reduction of fatigue life at stress amplitudes corresponding to high-cycle fatigue.

The drawing of 12X18H10T stainless-steel wire with a cupronickel coating and cadmium-plated carbon-steel wire is considered. The quality of zinc-plated carbon wire is shown to depend on the drawing temperature, which must be stable.

The chapter begins with introduction of different types of copper and copper alloys used in practice. Different types of heat treatments employed for the materials are listed and discussion on individual process, viz. homogenization, annealing after cold working is made. The effect of these heat treatments on changes in structure and properties and the reasons thereof are explained in detail. The stress relieving operation carried out with cold worked materials is also narrated. After discussing the generic issues, heat treatment of important alloys is individually narrated. Following this, the heat treatment of various bronzes is enumerated in detail. Besides these, the critical heat treatment of other copper alloys like chromium copper, zirconium copper, and chromium–zirconium–copper alloys are described with highlights of criticalities in heat treating these important alloys. Separately elaborate discussion is made of the different heat treatment of nickel alloys. Annealing, stress relieving, and cold work followed annealing of conventional nickel alloys are highlighted. That nickel alloyed with Al, Nb, Ti, and Si is capable of precipitation hardening is illustrated with specific examples. Data regarding heat treatment and the consequent properties of copper and nickel alloys are furnished in the form of tables. Due scientific explanations are provided where ever felt necessary.

The electrochemical reduction of dioxygen at cupronickel (Cu-30Ni) alloy electrodes is studied in alkaline 1.0 M KOH aqueous solution in the presence of intense ultrasound and compared to the case of the reduction of oxygen at platinum. In the presence of ultrasound an overall four-electron reduction process is detected at a freshly polished Cu-30Ni alloy electrode, but the response is shown to diminish after scanning the potential positive. In contrast to the case of pure copper or pure nickel electrodes, prolonged treatment with ultrasound is shown to recover the original response. Sono-ring-disk voltammetry is used for the detection of products generated electrochemically at the alloy disk electrode in the presence of ultrasound. Under an atmosphere of argon the oxidation of the surface of the Cu-30Ni alloy electrode is shown to be associated with a leaching process such as the loss of cuprite, Cu(OH)] 4 2- . In the presence of oxygen the formation of hydrogen peroxide anions, HO 2 - , is demonstrated to remain only a minor reaction pathway (

Introduction Contact with nickel-releasing coins as a cause of hand dermatitis has been debated. Aim Studying a hand dermatitis risk from handling Kuwaiti cupronickel coins among nickel-allergic and nickel non-allergic subjects. Material and methods One hundred hand dermatitis patients (group I: nickel-allergic) and 100 matched patients (group II: nickel non-allergic) were selected from over 500 hand dermatitis cases seen between September 2014 and September 2015. Nickel released from Kuwaiti cupronickel coins immersed in a standardized artificial sweat solution was measured at 1, 24, 48, 144 and 168 h at room temperature. Subjects in both groups were exposed to nickel releasing coins. The process was repeated after 3 months using nickel coated coins as controls. Results Nickel released from 20, 50 and 100 fils Kuwaiti cupronickel coins at 1 week was 28.64, 32.76, 35.76 μg/cm2/week, respectively. Ninety-one patients (29 males, 62 females) in group I and 87 patients (38 males, 49 females) in group II completed the study. 47.3% in group I vs. 13.8% in group II developed dermatitis on exposure to nickel releasing coins. Nickel coated coins resulted in dermatitis in 8.8% of group I vs. 5.7% in group II. Conclusions Nickel is released significantly from cupronickel Kuwaiti coins. Handling of coins caused dermatitis more often in patients with nickel-allergy compared to nickel non-allergic patients.

Electrodeposition is the major method for source preparation of actinides, Pu, Am, Th, U using stainless steel discs and spontaneous deposition for Polonium using discs of silver. Worldwide coins are manufactured of bronze, steel, copper plated steel, cupronickel, brass and alloys of Cu–Ni–Zn. The price of the coins which can be used have a value between 0.1 and 0.4 Euro considerably cheaper than electropolished stainless steel discs, 0.8 Euro. This investigation had the purpose to show the possibility to use coins from different countries for source preparation, the energy resolution and deposition efficiency. We obtained plating recoveries ranging from 50 to 100 % and the energy resolution varied between 21 and 75 keV for the different coins tested.

Additional tertiary treatment of secondary-treated municipal wastewater (MWW) is necessary to reduce its scaling potential for use in power plant cooling systems. In this study corrosiveness of three tertiary-treated municipal wastewaters (acidified MWW, MWW treated by nitrification–filtration, and MWW treated by nitrification–filtration and granular activated carbon adsorption) towards mild steel, copper, and cupronickel alloys was assessed. pH, ammonia, and organic matter were identified as important corrosion influencing parameter in tertiary-treated municipal wastewater. Corrosiveness of wastewater towards metal alloys increased after tertiary treatments. However, corrosion of mild steel and copper alloys was controlled within acceptable limits using the corrosion inhibitor tolyltriazole.

Corrosion of the metal oxide surface of cupronickel (CuNi) alloys is a problem in applications such as household water pipes, industrial pipelines, and marine vessels. On other substrates, thin films have been used as barriers to corrosion. Here, the formation of self-assembled monolayers (SAMs) on the CuNi metal oxide surface has been investigated. Stable, well-ordered SAMs of octadecylphosphonic acid (ODPA) and 16-phosphonohexadecanoic acid (COOH-PA) were formed on the metal oxide surface of CuNi foils (55% Cu/45% Ni) using a solution deposition method. The ODPA modified surfaces could be used to provide a non-reactive barrier that inhibits corrosion of the CuNi metal oxide surface. Meanwhile, COOH-PA films could be used for further surface reactions such as surface initiated polymerization, in which polymer coatings are grown directly from a well-ordered film. Film-modified surfaces were characterized using diffuse reflectance infrared Fourier transform spectroscopy, contact angle analysis, and matrix assisted laser desorption ionization time of flight mass spectrometry. The ability of the films to inhibit corrosion by limiting oxidation of the CuNi surface was assessed using cyclic voltammetry.

Superconducting tapes from MgB2 and powders of magnetic Ni, Co, and non-magnetic Ti were fabricated by cold-processed powder-in-tube (PIT) method. The cupronickel was used as sheath material and no heat treatment was applied. The increasing of critical current was observed in the samples with additions of nickel and titanium. The microstructure and phase analysis of tape core was performed by X-ray diffraction spectroscopy. A direct correlation between type and amount of additives, and the critical current of the tapes has been observed.

An instantaneous corrosion rate (ICR) monitoring technique, suitable for application in recirculating cooling water systems, is useful for rapid appraisal of corrosiveness of the aqueous system with respect to metal and metal alloys of interest. In this study the instantaneous corrosion rates of mild steel, copper, and cupronickel alloys were measured at various times during an exposure period by electrochemical polarization resistance measurements using a three-electrode system. The average corrosion rates (ACR) were also determined by the gravimetric weight loss method to correlate with the ICR data. Stainless steel was used as the reference electrode to replace the standard saturated calomel electrode for increased robustness of the system in pilot-scale cooling systems. A side-streamflow channel unit was designed to hold the three electrodes in flowing cooling water. Use of stainless steel as a reference electrode was reliable and ICR was monitored intermittently for 28 days. Integration of the ICR data from the pilot-scale cooling towers correlated well with the ACR results, with similar correlation coefficients obtained from bench-scale experiments.

A novel hydrophobic film was prepared by Stearic acid (SA) chemically adsorbed onto the cupronickel B30 surface. The film properties were characterized by means of water contact angle measurement and electrochemical techniques. The results indicate that the structure of the adsorbed film is hydrophobic, and the contact angle is 113.82° for water. AC impedance and polarization curve measurements show that the corrosion resistance of cupronickel B30 modified by stearic acid is improved remarkably, and the inhibition efficiency reached 66.85%. After hydrophobic modified by stearic acid, the inhibition efficiency could reach 88.85% in 3% NaCl solution with the concentration of 0.1 g/L Na2WO4.

Minor Fe additions are widely added to enhance the corrosion resistance of cupronickel alloys. The present paper aims at optimizing the amounts of Fe in Cu 70 (Ni,Fe) 30 (at.%) alloys using a cluster-plus-glue-atom model for stable solid solutions. By this model, it is assumed that one Fe atom and 12 Ni atoms formed a Fe-centered and Ni-surrounded cube-octahedron cluster and the isolated FeNi 12 clusters embedded in a Cu matrix. The stable solid solution alloy composition of Fe-modified Cu 70 Ni 30 alloy was described by a cluster formula [Fe 1 Ni 12 ]Cu 30.3 = Cu 70 Ni 27.7 Fe 2.3 (at.%). The effect of homogenizing annealing treatment on the microstructure and corrosion resistance was also investigated by XRD, TEM and electrochemical corrosion measurements. The corrosion test indicates that the Cu 70 Ni 27.7 Fe 2.3 alloy annealed at 800 °C for 5 h possesses the best corrosion resistance in 3.5% NaCl solution.

The gravimetric weight loss method and the electrochemical polarization resistance methods were combined to evaluate instantaneous corrosion rates for metals and metal alloys in industrial cooling-water systems. Metal and metal−alloy samples were exposed to synthetic cooling water in a bench-scale recirculating system constructed to study corrosion under flow conditions similar to those of a cooling-water system. The measurements yielded by both methods were related through a coefficient, B′, to convert polarization resistance measurements to instantaneous corrosion rates. The metals and metal alloys tested in this study included mild steel, aluminum, copper, and cupronickel. B′ was observed to change with time initially but approach a constant value for long-term exposure (>3 days) for most metal materials. B′ values varied with metal or metal alloy studied. It was concluded that combining both methods to determine the B′ value for a metal or a metal alloy under particular exposure conditions provides a ...

Minor M (M = Fe, Mn, Cr) additions are widely added to enhance the corrosion resistance of commercial cupronickel alloys. The present paper aims at optimizing the amounts of M in Cu 70 (Ni,Fe,Mn,Cr) 30 (at.%) alloys using a cluster-plus-glue-atom model for stable solid solutions. By this model, it assumed that 1 M atom and 12 Ni atoms formed an M-centered and Ni-surrounded cube-octahedron cluster and the isolated M 1 Ni 12 clusters are embedded in a Cu matrix, conforming to a cluster formula [M 1 Ni 12 ]Cu 30.3 = [M 1/13 Ni 12/13 ] 30 Cu 70 . A structure of this kind satisfies ideally the nearest neighbor requirement, i.e. only M–Ni and Ni–Cu neighbors are allowed and the unfavorable Cu–M pairs are avoided, and hence it describes a stable solid solution structure with good thermal stability. Electrochemical corrosion measurements indicated that [(Fe 0.6 Mn 0.25 Cr 0.15 ) 1 Ni 12 ]Cu 30.3 had the best corrosion resistance in 3.5% NaCl aqueous solution.

Corrosion inhibition of Cu–30Ni alloy in aerated 0.5 M H2SO4 solution by cysteine, an amino acid, has been investigated. Potentiodynamic polarization and impedance spectroscopy (EIS) at open circuit potential were performed. Corrosion current density was also determined from colorimetric experiments. Voltammetric curves showed that cysteine addition to 0.5 M H2SO4 affects largely the cathodic process; shifting the corrosion potential to more negative values and decreasing significantly the corrosion current density. The inhibiting efficiency reaches a value of 91% at an inhibitor concentration of 10−3 M. Impedance data reveal the adsorption of the inhibitor and the surface relaxation process due to nickel. Polarization resistance deduced from impedance measurements or voltammetric experiments are in a good agreement.

Copper nickel alloys 90/10 and 70/30 are used extensively in saltwater systems operating on marine platforms and offer high corrosion and biofouling resistance. However, systems using these materials were reported to fail prematurely. Preliminary investigations revealed pollution of harbor waters with tangible levels of ammonia and sulphides which was reported to be the primary cause of failure. The present author(s) have performed laboratory and field investigations to identify the stress-material-environment interaction of the copper nickel alloys extensively in use on seawater system of marine platforms. Results obtained point to the fact that polluted seawaters can affect the material properties of the alloy leading to premature failure(s) of systems at stresses well below the designed stress. The paper presents the correlation of the results of the laboratory and field tests of 90/10 and 70/30 copper–nickel alloys in seawaters polluted with ammonia and sulphide pollutants.

The objectives of the present investigation were to characterize ammonia-producing bacteria (Bacillus sp.) and study its impact on biodeterioration of cupronickel alloy 90:10. in a nitrogen free environment. It is well known that iron sulphate and molybdenum are good inhibitors when used in a cooling water system. The interactions between inhibitor and ammonia producing bacteria on the corrosion of cupronickel 90:10 were studied. The predominated ammonia producing bacteria Bacillus sp. (AG1-EU202683; AG2-EU202684; AG3-EU202685 and AG4-EU202686) were identified by 16S rRNA gene sequencing from the biofilm. These bacteria fixed with atmospheric nitrogen for their cell protein synthesis and converted into ammonia. Ammonia enhanced pH and ammonical solution were formed in the presence of Bacillus spp. which acted as an etchant. The presence of some anodic spots in the presence of bacteria was affected by ammonia and then underwent pitting corrosion. The present study reveals that Bacillus spp. encourage intergranular attack without any stress in the cooling water system.

PurposeThe purpose of this paper is to evaluate the effect of seawater temperature on the corrosion behaviour of 90‐10 cupronickel alloys. Also, to investigate the effect of thiosulphate additions (one of the major sulphide oxidation products in seawater) on the alloy corrosion rate in seawater.Design/methodology/approachPotentiodynamic polarization measurement (DC) was used to estimate the corrosion rate of the cupronickel alloy in seawater with and without thiosulphate species (50‐650 ppm).FindingsIt was observed that the cupronickel alloy suffered accelerated corrosion as the seawater temperature was raised from 25 to 50 or 80°C. The increase in the corrosion rate was found to correspond well with the negative shift in the free corrosion potential. Thiosulphate addition was found to depend on the test temperature. At 25°C, thiosulphate activated the alloy dissolution rate and the higher were the thiosulphate concentrations, the higher was the corrosion rate. At 50 or 80°C, however, thiosulphate promoted the dissolution rate at early stages, but seemed to interfere with the surface film formation later on, producing a black film that effectively decreased the alloy corrosion rate. At higher potentials, however, the film became non‐protective, leading to accelerated corrosion once again.Originality/valueThis paper explains the corrosion behaviour of 90‐10 cupronickel alloys in seawater as a function of test temperature and thiosulphate additions.

The failure of 90/10 cupronickel heat exchanger tubes in hydrogen coolers were seen after few years in use. The tubes had river water flowing at a velocity of 2.5 m/s. The shell side was exposed to hydrogen at a pressure of 3.5 kg/cm2. The inlet and outlet temperature of the cooling water of the cooler are 37 °C and 47 °C, respectively. The failures were pin hole type with a thick layer of muck deposit on the inner side of the tube. The metallographic studies carried out for the tube showed a well annealed microstructure. The region near the pit showed attack along the grain boundaries with dislodging of the grains. The electron probe micro analysis (EPMA) studies revealed the denickelification near the pits. The energy dispersive spectroscopy (EDS) analysis of the pit showed the presence of copper chloride and also the variation in the copper and nickel concentration with respect to the unaffected regions of the tube. Microbial presence was detected in the water as well as the muck deposits in the tubes. The pin hole failure of the tube was a result of the combined action of the chloride as well as the deposits in the tube which gave a conducive environment for the microbial activity to flourish which has caused the propagation of the pit through intergranular corrosion.

National Natural Science Foundation of China [20406009]; Shanghai Education Committee [06ZZ67]; Shanghai Committee of Science and Technology [062312045]; Xiamen University [200512]; Key Discipline of Shanghai Education Committee of China [P1304]

In this paper, Titanium tetrachloride (TiCl4) is analyzed/assessed and proposed as a new potential working fluid in Rankine Cycles. Besides its good thermodynamic properties, TiCl4 is in fact a fairly low cost, non-carcinogenic fluid, with zero Global Warming Potential (GWP) and Ozone Depleting Potential (ODP) and it is currently employed in high temperature industrial processes. It is however very reactive with humid air and water. A preliminary thermodynamic analysis confirms its possible application in power plants with maximum temperature up to 500 °C, considerably higher than the ORC state-of-the-art technology, performing electrical efficiencies as high as 35-40%. This suggests the potential use of TiCl4 as an alternative fluid in ORCs allowing the exploitation of high temperature sources (up to 500 °C), typically used in steam cycles. To assess the possibility of operating the cycle in such high temperature conditions, we carried out an experimental thermal stress analysis, showing that the fluid is remarkably stable at temperatures up to 500 °C, even in presence of P91 and Cupronickel, two materials typically employed in the high temperature section of power cycles. © 2016 Elsevier Ltd. All rights reserved.

Cupronickel pipes are widely used in cooling systems. Under this application, localized corrosion is observed, particularly associated with selective corrosion of nickel (denickelification). This work studied the denickelification process in solution-treated cupronickel alloys 90-10 (Cu-10wt%Ni), with aluminum and iron additions, in 0.01 M, 0.1 M, or 0.6 M sodium chloride (NaCl) aqueous solutions. Polished surfaces of the studied materials were submitted to potentiodynamic polarization, and after that, the polarized surfaces were studied using optical microscopy (OM) and scanning electron microscopy (SEM) assisted by energy-dispersive spectroscopy (EDS). A passivity break potential (Epb) was determined in all solutions, related to the initiation of selective corrosion of nickel. When submitted to cyclic potentiodynamic polarization, alloys with higher Epb showed the higher nickel losses in localized spots. However, potentiodynamic polarization tests conducted in 0.01 M NaCl until current densitie...