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This study aims to investigate the effect of coatings prepared by the addition of copper-aluminum alloy powder on the corrosion behavior of 90/10 copper-nickel alloy.

Coatings of copper-aluminum alloy powder at different contents (Wt.% = 50%, 60%, 70% and 80%) were prepared by the high-temperature heat treatment process. The microstructure and component of the coatings were characterized by scanning electron microscope, X-ray diffraction, energy dispersive spectrometer and X-ray photoelectron spectroscopy. The electrochemical properties of the coating were explored by electrochemical impedance spectroscopy.

The results show that the aluminized layer was successfully constructed on the surface of 90/10 copper-nickel alloy, the composition of the coating was composed of copper-aluminum phase and aluminum-nickel phase, the existence of the aluminum-nickel phase was formed by the diffusion of Ni elements within the substrate and because of the diffusion, the Al-Ni phase was distributed in the middle and bottom of the coating more. The Al-Ni phase is considered to be the enhanced phase for corrosion resistance. When the copper-aluminum alloy powder content is 70 Wt.%, the corrosion resistance is the best.

The enhancement of corrosion resistance of 90/10 copper-nickel alloy by the copper-aluminum alloy powder was revealed, the composition of the aluminized layer and the mechanism of corrosion resistance were discussed.

The 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.

Potentiodynamic polarization measurement (DC) was used to estimate the corrosion rate of the cupronickel alloy in seawater with and without thiosulphate species (50‐650 ppm).

It 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.

This paper explains the corrosion behaviour of 90‐10 cupronickel alloys in seawater as a function of test temperature and thiosulphate additions.

This study aims to investigate the effect of changes in iron content in 70/30 copper–nickel alloy on the corrosion process.

70Copper–30Nickel-xFe-1Mn (x = 0.4,0.6,0.8,1.0 Wt.%) alloy were prepared by the high frequency induction melting furnace. The scanning electron microscope, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy were used to analyze the morphology and component of the corrosion product film.

The results show that the corrosion resistance of 70/30 copper–nickel alloy added with 1.0%Fe is the best, and the film is divided into inner dense Cu2O composite film and outer hydration loose layer; XRD showed that after adding 1.0% Fe, the content of Cu2(OH)3Cl in the corrosion product film was significantly reduced, while the content of Cu2O remained unchanged; XPS showed that nickel accumulates in the inner layer of corrosion product film; the stage growth mode of the film, the role of nickel in it and the enrichment mechanism of iron in the inner film were summarized and discussed.

The changes in the composition and structure of the corrosion product film caused by the iron content are revealed, and the mechanism of the difference in corrosion resistance is discussed.

The use of materials in marine environments has traditionally been associated with ships. However, in recent years, important new industries have grown up which present new material problems. Notable amongst such industries are offshore oil production and desalination (production of fresh water from seawater). Also, requirements for large amounts of cooling water by modern industry have often resulted in siting of plants by the ocean, particularly in arid areas such as the Middle East. This has increased interest in the use of materials for handling seawater.

A review of the main metals and alloys in commercial use for resisting sea‐water corrosion

Introduction The degree of adsorption of organic inhibitors on a metal surface in presence of halide anion is predominantly influenced by the synergistic effect. The synergistic effect brings about an improvement in inhibition as a result of chemisorption or physical adsorption depending on the nature of the interaction between the halide and the cation of the inhibitor. This effect is partly attributed to the stabilization of the adsorbed anion layer by an organic cation through a possible covalent linkage. The degree of availability of electrons influences the mode of adsorption. Investigations on ferric ion corrosion have shown that the synergistic inhibition effects the corrosion processes by primarily increasing the polarization of the cathodic reaction. The adsorption of quinoline on 18–8 steel in the presence of halider ions is predominantly influenced by the synergistic effect. It has been found that the addition of smaller concentration of quinoline inhibits the cathodic reaction and higher concentrations of quinoline inhibit the anodic reaction as well. According to Iofa the formation of an adsorbed layer of positively charged ion retards the transfer of cation through a binary layer and lowers the transfer rate. Work on amines has shown that tertiary and secondary amines are stronger than the primary amines as a result of increase of dipole moment of the doublet, increase of ionisation energy and increase of polarizability. Basicity and stearic effects, both are important. The high effectiveness of cyclic amines with more than seven carbon atoms appears to be correlated with the character of the free electron. It has been shown that whereas the organic compounds of cationic type were weakly absorbed on the iron surface in H2SO4 the addition of halides produced a considerable increase in the adsorption. Cavallaro and others have shown that several nitrogen molecules inhibit both the anodic and cathodic reactions.

The purpose of this paper is to investigate the effect of iron content (2% and up to 6% Fe) on the corrosion behavior of 90Cu‐10Ni alloys in 3.5% NaCl at different temperatures (23, 50 and 80°C) under stagnant conditions and fluid flow (with an agitation speed of 350 and 900 RPM). The laboratory study was conducted following a failure of high iron content (up to 6%) 90Cu‐10Ni heat exchanger tubes in a desalination plant.

Potentiodynamic polarization measurement (DC) was used to estimate the corrosion rate of the 90Cu‐10Ni alloys in NaCl solutions under stagnant and fluid flow conditions.

It was found that the higher iron content cupronickel material suffered higher corrosion rates in all tests. The intensity of the corrosion attack of both materials was increased significantly with increasing experimental temperature or flow velocity. The results support a previous prediction that the presence of excess iron (well above 2%) has played a major role in corrosion failure of 90Cu‐10Ni heat exchanger tubing material in seawater.

This paper explains the role of iron content on the corrosion behavior of 90Cu‐10Ni alloys in 3.5% NaCl under stagnant and fluid flow conditions.

Sprayers for acid Recently added to the Spray Systems range of pump‐up sprayers is the 2AS Acid Sprayer. Specially designed for spraying corrosive chemicals, only plastic parts are in contact with the chemical, viton gaskets being used for sealing. The pump rod and piston plate are in stainless steel to ensure that no rust or corrosion can build up and restrict the action.

ICI Resins is rewarded for efforts in China Preparation and perfection of trial formulations by ICI Resins has led to sales of ‘NeoRez’ polyurethane resin and ‘Winnofil’ thixotropes to Nan Ji paint in Shanghai for car underbody sealer products. This is ICI Resins' first business with the emerging automotive industry of the Peoples Republic of China.

TN38 materials for seawater pipeline systems. “Materials for Seawater Pipeline Systems” published by Copper Development Association, describes the factors that need to be taken into account when selecting materials for pipelines handling seawater in ships, offshore oil and gas platforms, desalination plants and shore‐based industry using seawater services.