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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.

In this study, the characteristics of thin semi-rigid cables composed of different conductors and with outer diameters ranging from 0.86 to 1.19 mm were investigated at low temperatures. The thermal conductance was measured between approximately 1 and 8 K, and the frequency dependence of the attenuation in the cables was obtained at 3 K. The electrical conductors used in the cables were alloys: beryllium copper, brass, stainless steel (SUS304), phosphor bronze, cupronickel (CuNi), and niobium–titanium (NbTi). The thermal conductance of a commercial miniature coaxial cable with braided wires forming the outer electrical conductor was also examined for reference. The measured thermal conductance was compared to published data and that generated from material libraries and databases. Among the measured cables using normal metals, the semi-rigid cable composed of SUS304 conductors and a polytetrafluoroethylene insulator showed the lowest thermal conductance. The transmission performance of the semi-rigid cables using SUS304 or CuNi was improved by plating the central conductors with a silver coating of approximately \(3~{\upmu }\hbox {m}\) thickness, and their thermal conductance with the plating increased by approximately one order of magnitude. The superconducting NbTi semi-rigid cable exhibited the lowest thermal conductance of all the cables considered in the present study along with very small attenuation up to above 5 GHz.

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.

The corrosion behavior of cupronickel alloy immersed in the simulated seawater in or without the presence of sulfate-reducing bacteria (SRB) was studied. The results of scanning electronic microscopy and electrochemical impedance spectra reveal that corrosion of the sample immersed in the simulated seawater with SRB was more serious than that immersed in the simulated seawater without SRB. The atomic force microscopy images show that after immersion for 15 days, the surface roughness of the sample in the simulated seawater with SRB was higher than that of the sample in the simulated seawater without SRB. The analysis of confocal laser scanning microscopy indicates that the average depth of the pits on the surface of the sample in the simulated seawater with SRB was almost twice deeper than that of the sample in the simulated seawater without SRB.

Cupronickel B10—an important material used in aircraft carriers—exhibits excellent electrochemical and mechanical properties, such as high corrosion resistance and weldability. The Split-Hopkinson pressure bar (SHPB) test is a classical method to obtain the dynamic mechanical properties of solid materials. However, the deformation temperature has long been ignored in SHPB studies, which results in low accuracy of the material constitutive model. Thus, in this study, a new method for obtained the deformation temperature was proposed and the modified material equation was validated using experimental data. Quasi-static compression and SHPB experiments were conducted with a thermocouple. The results revealed that the deformation temperature of the quasi-static tests was nearly zero, whereas that of the SHPB experiments ranged from 40 to 90 °C. Therefore, the method developed to describe the deformation temperature can be used to improve the precision of SHPB experiments, as demonstrated for the case of cupronickel B10.

High temperature deformation behavior of BFe10-1-2 cupronickel alloy was investigated by means of isothermal compression tests in the temperature range of 1,023~1,273 K and strain rate range of 0.001~10 s–1. Based on orthogonal experiment and variance analysis, the significance of the effects of strain, strain rate and deformation temperature on the flow stress was evaluated. Thereafter, a constitutive equation was developed on the basis of the orthogonal analysis conclusions. Subsequently, standard statistical parameters were introduced to verify the validity of developed constitutive equation. The results indicated that the predicted flow stress values from the constitutive equation could track the experimental data of BFe10-1-2 cupronickel alloy under most deformation conditions.

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.

We developed thin semi-rigid coaxial cables for use as readout noise filters in low temperature experiments. The cables reported here had an outer diameter of 0.86 mm, and consisted of a standard cupronickel (CuNi) alloy as a seamless outer conductor and polytetrafluoroethylene (PTFE) as a dielectric material. The inner conductor was superconducting niobium-titanium (NbTi) covered by a CuNi cladding layer with a thickness of 0, 13, or 38 μm. The thermal conductance and transmission properties for the cables were measured at cryogenic temperatures and compared to those for a conventional CuNi semi-rigid cable. Between 1.4 and 8.4 K, the thermal conductance was similar to that for the conventional cable because the contribution from the cladding was estimated to be small. On the other hand, measured at about 3 K, the attenuation at high frequency up to 10 GHz differed in that the cutoff frequency increased with decreasing CuNi cladding thickness. For a cladding thickness of 38 μm, the 3 dB cutoff frequency for a 1-m-long cable was 100 MHz, whereas for a cladding thickness of 13 μm, it was 500 MHz. This type of semi-rigid cable can, therefore, be used as a low-pass filter whose attenuation characteristics can be tailored by changing the thickness of the cladding layer.

Cupronickel alloys, reinforced by L12 precipitates, offer a high strength, corrosion resistant and anti-bio fouling material for marine engineering applications. These alloys exhibit complex precipitate nucleation and growth mechanisms that must be fully understood in order to optimise the mechanical properties. In this work, the microstructural characteristics of the Cu-Ni-Al based alloy, Hiduron® 130, have been assessed in the as-received condition and following 100-h thermal exposures at 500, 600, 700 and 900 °C and after a two-stage exposure at 900 °C for 100 h followed by 500 °C for 100 h. The L12 phase was observed to precipitate both discontinuously and continuously and its subsequent coarsening was characterised alongside measurements of the lattice misfit. The hardness of the alloy was found to decrease with increasing exposure temperature up to the L12 solvus and correlated with the evolution of the L12 precipitates, the alloy grain size and the fraction of the discontinuously formed L12 phase.

�������� �������������� �������������� �������������������� �� ���������������������������� ���������������� Cu ���Ni �������� ������������������ ���������������� ��� �������������������� �������������� �������������� ������ �������������������� ������������ ������ ������ ����������������. ������������ ���������� �� ���������������� �������������� �������������������������� ���������������� 75%Cu ��� 25% ���� ������������ ������������ �������������������� �������������� , ���� ������������ ������������������������������ ����������. �������������������� ������ �������������������� ������ ������������������ ���������� �� ������������������ ����������������, �� ����������������������, �� ����������������, ���� pH ������ ���� �������������������������� ������ ���������������� ������ ������������. �������� �� �������������� ������ ����������������, ������ ������ �� ���������������������� ������ ���������������� ������ ������������ ���������������������������� �������� ���������������������������� XRF. ������������������������ ������������������ ���� ������������ �������� �������������� �������������� ���������������������� ������ �������������������� ���� ���������� �������� ������ ���������������� ������������������ ������ ������ ������������ ������ �������������� ������������������������ ������ ������������ ������ �������������� (������ �������������������������� 1,27 ��� 3,06 g���L-1 Cu, ������ ������������������������ ���� 5-12 g���L-1 CuSO4.5H2O). ����������������������, ������������ ������ �������������������� ���������������� (0,3 ��� 2,0 A���dm-1) ���������� ������������������ ������������������ ������������������������������ ���� ��������������. ���� ������������������������ ������ �������������� �������� ���������������������� ������������������������ �������� ������������ ������������������������������ ����������, �������� ������������������������ ������������������ ���� ���������������� �������������������� ���������������� ������������������������������ ����������, ���� ���������������������� ������������ ������������������������ (35 ��� 150) ���� ���������������� ������������������������ �������������������� ���������������� (0,2 ��� 1,5 A���dm-1) ������ ���������������������� ������������ ���������������������� Cu (0,76 ��� 3,06 g���L-1 Cu). �������� ������ �������� ������������ �������� ����������������������, �������� ������ ���� ���������� ������ ������������������������������ ����������, ������������������������ ������������ ������ ������������������������������ ������ ������������ ������ �������������� ���� ������ ������������ ������ �������������������� ���������������� ������ ������ ������������ ������ ������������������������ ������ ������������ ������ ��������������, ������ ������������ ������ �������������� ������������������������ ���������������� (18,5 ��� 29,7 g���L-1 Ni, ���� ���������� ������������������ ���� ������������������ ������ ���������������������� ���� 50-100 g���L-1 NiSO4.6H2O + 30 g���L-1 NiCl2 . 6H2O) ������ ������������ ������ �������������������� ���������������� ������������ �������������� ������������������ ������������������������������ ���� ��������������. ������ ������ ���������������� �������������������� ���� ���������� ���������� ������ �������������������� ���������������� 70-80% Cu, ������������������ ������������������ �� �������������� ���� ������������ ���������������� ������ ���������������������� ������������ ������ ��������������, �������� ������������������ ������ ���������� Cu/Ni ������ ������������. �������� ������ ������������������ ���������������� ( ������������������ ���������������� 0.22 A ��� dm-1, �������������� �������������� 0,76 g ��� L-1 Cu + 29,7 g���L-1 Ni, 150 ������������, ~2L ���������� ��������������, ������������ ���������������������� Cu 34 mL ��� h-1 �������������������� 200 g ��� L-1 CuSO4.5H2O) ���������������������������� �������������� ���������������� 75% Cu ��� 25% Ni �������������� ������������ 9.5��m �������� 6.5h ��������������������������., In the present work, the electrodeposition of Cu ��� Ni alloys through an alkaline citrate-ammonia bath of metal sulfates and chlorides was studied. The aim is to develop a 75% Cu - 25% Ni alloy plating method in a rotating drum cell on multiple steel tablets. Parameters affecting the process are current density, temperature, stirring, pH, and metal concentrations in the bath. The composition of of both the alloy and the bath was determined by XRF spectroscopy. Preliminary experiments on a single tablet showed copper - enriched deposits upon bath stirring and increased copper bath content (in the range of 1,27 ��� 3,06 g���L-1 Cu, that correspond to 5 - 12 g ��� L-1 CuSO4.5H2O). Correspondingly, an increase in current density (0,3 ��� 2,0 A ��� dm-1) gave nickel ��� enriched deposits. The single electrode cell conclusions were applied to the rotating drum cell, where experiments were performed on different drum shapes, on a number of substrates (35 - 150) using different current densities (in the 0.2 - 1.5 A ��� dm-1 range) and different initial CuSO4.5H2O concentrations (in the 3 - 12 g ��� L-1 range). Similarly to the single electrode cell, there was an increase in the deposit���s copper content as the current density decreased or the bath���s copper concentration increased. An increase in Ni content is seen upon increasing nickel concentration (in the range of 18,5 ��� 29,7 g���L-1 Ni, that corresponds to 50-100 g���L-1 NiSO4.6H2O + 30 g���L-1 NiCl2 . 6H2O), which was in excess, and increasing current density. In obtaining deposits within 70-80% at Cu concentration, it was crucial to finally adjust continuous replenishment of Cu in solution, in order to keep the Cu/Ni ratio constant. Under optimal conditions (current density of 0,22 A ��� dm-1, bath composition of 3 g ��� L-1 CuSO4.5H2O, 29,7 g���L-1 Ni, 150 substrate tablets, ~2L of bath volume, 34mL ��� h-1 addition of a 200 g ��� L-1 CuSO4.5H2O solution) deposits of a 75% Cu ��� 25% Ni composition and 9.5��m thickness were typically obtained after 6.5h of plating operation.

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.

Cupronickel alloys such as 70/30 Cu-Ni have excellent resistance to sea water corrosion and anti-fouling properties, and thus have been widely used for naval and offshore applications. Traditionally, arc welding and brazing processes have been used to weld such materials. In contrast, laser beam welding is a promising technology due to its high productivity, good process flexibility and reliability, and good welding integrity. In the present work, a high power fiber laser system is used to weld 5-mm thick 70/30 Cu-Ni alloy plates in a configuration of butt joints. Then, the laser welded joints are evaluated in terms of microstructures, defects, and mechanical properties (hardness, face and root bend, and tensile) in accordance with the applicable International Organization for Standardization and Defence Standard specifications. Keywords: Laser welding, Cupronickel alloy, Butt joint, Microstructure, Tensile properties, Bend testing

The composition of seawater plays a very significant role in determining the severity of corrosion process in marine assets. The influential contributors to the general and pitting corrosions in marine structures include temperature, dissolved oxygen (DO), salinity, PH, chlorides, pollutants, nutrients, and microbiological activities in seawater. The Cu-Ni (90/10) alloy is increasingly used in marine applications such as heat exchangers and marine pipelines because of its excellent corrosion resistant properties. Despite the significant advancements in corrosion shielding procedures, complete stoppage of corrosion induced metal loss, especially under rugged marine environments, is practically impossible. The selection of appropriate metal thickness is merely a multifaceted decision because of the high variability in operating conditions and associated corrosion rate in various seawater bodies across the globe. The present research study aims to analyze the early phase of corrosion behavior of Cu-Ni (90/10) alloy in open-sea conditions as well as in pollutant-rich coastal waters of the Arabian Sea. Test samples were placed under natural climatic conditions of selected sites, followed by the mass loss and corrosion rate evaluation. The corrosion rate in the pollutant-rich coastal waters was around five times higher than in the natural seawater. A case study on marine condenser (fitted with of Cu-Ni 90/10 alloy tubes) is presented, and a risk-based inspection (RBI) plan is developed to facilitate equipment designers, operators, and maintainers to consider the implications of warm and polluted seawater on equipment reliability, service life, and subsequent health inspection/ maintenance.

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.

The present work aims to analyze the failure resulting from temperature change and its influence on the corrosion and fouling resistance of the cupronickel Cu-Ni 90/10 in simulated marine solution to predict the removal fouling temperature in the desalination heat exchanger and how affects fouling composition and morphology. The Cu-Ni 90/10 electrochemical behavior has been studied through: polarization tests, following the evolution of open circuit potential (OCP) and electrochemical impedance spectra (EIS) with immersion time under thermal and hydrodynamic conditions close to those prevailing in the heat exchanger of desalination industry. Electrochemical measurements show that the corrosion rate of Cu-Ni 90/10 alloy change with temperature, due to a competition between the formation of stable complexes on the metal surface and the dissolution of salts to generate aggressive ions in the corrosion medium. 60 °C ensures an equilibrium between the complexation reactions that promotes fouling stability, and fouling mitigation that leads to metal oxidation. In contrast, at high temperatures (80 °C), the dissolution of salts predominates over the complexation process. It can be deduced that 60 °C is a critical point for heat exchanger that promotes the formation of thin layer with low thermal fouling resistance that protects the installation against damage, maintain a good heat transfer and extend the cleaning scheduling of the machine. Surface analyses were performed by means Raman spectroscopy, SEM and EDS quantification, reveals the reinforcement of fouling by iron compound which make deposit more resistant at 60 °C.

The hot deformation behavior of BFe10-1-2 cupronickel alloy was investigated over wide ranges of deformation temperature and strain rate. The physics-based constitutive model was developed to predict the dynamic recovery (DRV) behavior of BFe10-1-2 cupronickel alloy at elevated temperatures. In order to verify the validity of the developed constitutive equation, the correlation coefficient (R) and average absolute relative error (AARE) were introduced to make statistics. The results indicated that the developed constitutive equation lead a good agreement between the calculated and experimental data and can accurately characterize the hot DRV behaviors for the BFe10-1-2 cupronickel alloy.

In this study, the gradient grain induced by punching deformation and recovery treatment on a cupronickel alloy surface sample were investigated, and their effects on corrosion resistance were measured by atom force microscopy (AFM), X-ray diffraction (XRD), electrochemical measurement, electron work function (EWF), and contact electrical resistance (CER). The cupronickel alloy surface experienced punching deformation for 60 min and recovery at 300 °C for 1 h to produce gradient surface. The grain size measured by XRD is bigger than that measured by AFM, due to X-ray intensity of 95 % produced at the depth of 12–20 μm for the crystal planes of (111), (200), and (220). The gradient grain surface, compared to the original surface, shows a 13.7-fold decrease in passivation current density (i p), and corrosion potential (E C) increases by approximately 9.8 %. These results are attributable to the increase in EWF and formation of passivation film with better adhesion and compactness after treatment.

True stress and true strain data obtained from isothermal compression tests on a Gleeble-3800 thermo-mechanical simulator, in a wide range of temperatures (1073-1323 K) and strain rates (0.001-10 s−1), has been used to evaluate the material constants of two constitutive models: the modified Zerilli-Armstrong and the strain compensation Arrhenius-type models. Furthermore, a comparative study was conducted on the capabilities of the two models in order to represent the elevated temperature flow behavior of BFe10-1-2 cupronickel alloy. The suitability levels of these two models were evaluated by comparing the accuracy of their predictions of deformation behavior, correlation coefficient (R), average absolute relative error (AARE), relative errors of prediction, and the number of material constants. The results show that the predicted values of these two models agree well with the experimental values of BFe10-1-2 cupronickel alloy except at the temperature of 1123 K and the strain rate of 1 s−1. Meanwhile, the strain compensated Arrhenius-type model can track the deformation behavior of BFe10-1-2 cupronickel alloy more accurately throughout the entire temperature and strain rate range, while fewer material constants are involved in the modified Zerilli-Armstrong model.

The effect of different annealing times on microstructure and properties of C71500 cupronickel alloy tubes were studied at the temperature of 800 °C. Electron backscatter diffraction (EBSD) technique was applied to analyze the change trend of the “special” grain boundaries proportion of alloy under different processing conditions. The difference of microstructure transformation between small and large annealing deformation was analyzed. The optimal process was verified by means of grain cluster analysis, “Σ3 regeneration model” verification, the relationship between grain cluster size and grain size, and the residual stress analysis. The results show that the static recrystallization (SRX) is the main process of the 70.55% deformation alloy tube after annealing at 800 °C. With the increase of annealing time, the proportion of low coincidence site lattice (CSL) grain boundary has no obvious pattern change, but the grain size can be controlled. The static recovery is the main process for the small deformation (9.57%) alloy tube at 800 °C annealing, and the proportion of low ΣCSL grain boundary reaches 78.00% after annealing for 15 min. The ideal microstructure could be obtained by the two stages rolling processes: “70% deformation + 800°C annealing, holding for 20 min; and 9.57% deformation + 800°C annealing, holding for 15 min”.

The present paper describes a failure investigation of a tube that had shown leakage in a shell and tube type heat-exchanger with 70/30 cupronickel tubes and mild steel baffles (13 nos.). Corrosion damage or thinning of the failed tube was found to have occurred from the outer surface at all the baffle locations. Further examination of the failed tube was done using an optical microscope, a scanning electron microscope equipped with energy dispersive spectroscopy, Raman spectroscopy and an instrumented microhardness indentation machine for hardness measurement. Based on the results, it was concluded that the failure and the loss in wall-thickness of the tube at locations where it was in contact with the mild steel baffles were caused by fretting corrosion. The focus of this investigation is to bring out the metallurgical changes and the surface conditions (including changes in microstructure and microhardness, mode of corrosion attack and type of oxides/corrosion products) of the tube material undergoing fretting corrosion at micro level. Recommendations to avoid such a failure are also suggested.

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 effects of aluminum on the mechanical properties and corrosion behavior in artificial seawater of Cu-Ni-Fe-Mn alloys were investigated. Cu-7Ni-xAl-1Fe-1Mn samples, consisting of 0, 1, 3, 5, and 7 wt % aluminum along with the same contents of other alloying elements (Ni, Fe, and Mn), were prepared. The microstructure of Cu-7Ni-xAl-1Fe-1Mn alloy was analyzed by Transmission Electron Microscopy (TEM), and its corrosion property was tested by an electrochemical system. The results show that the mechanical and corrosion properties of Cu-7Ni-xAl-1Fe-1Mn alloy have an obvious change with the aluminum content. The tensile strength has a peak value of 395 MPa by adding 3 wt % aluminum in the alloy. Moreover, the corrosion rate in artificial seawater of Cu-7Ni-3Al-1Fe-1Mn alloy is 0.0215 mm/a which exhibits a better corrosion resistance than the commercially used UNS C70600. It is confirmed that the second-phase transformation of Cu-7Ni-xAl-1Fe-1Mn alloy follows the sequence of α solid solution → Ni3Al → Ni3Al + NiAl → Ni3Al + NiAl3. The electrochemical impedance spectroscopy (EIS) shows that the adding element aluminum in the Cupronickel can improve the corrosion resistance of Cu-7Ni-xAl-1Fe-1Mn alloy.

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.