Nickel-copper alloy

The copper-nickels are single-phase solution alloys, with nickel as the principal alloying ingredient. The alloys most important for corrosion resistance are those containing 10 and 30% nickel. Table 18.11 lists these wrought alloys. Iron, manganese, silicon, and niobium may be added. Iron improves the impingement resistance of these alloys, if it is in solid solution. Iron present in small microprecipitates can be detrimental to corrosion resistance. To aid weldability, niobium is added. 

Wrought Copper-Aluminum Alloys Maximum Composition (%) 

Source From J.M. Cieslewicz. 1988. Copper and copper alloys, in Corrosion and Corrosion Protection Handbook, P.A. Schweitzer, Ed., 2nd ed.. New York Marcel Dekker. 

Flow velocities play an important part in seawater corrosion. Velocity-dependent erosion corrosion is often associated with turbulance and entrained particles. Recommended velocities for continuous service are as follows  

Alloy C71500 finds use in many of the same applications as alloy C70600. Sulfides as low as 0.007 ppm in seawater can induce pitting in both 

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Fluorine cannot be prepared directly by chemical methods. It is prepared in the laboratory and on an industrial scale by electrolysis. Two methods are employed (a) using fused potassium hydrogen-fluoride, KHFj, ill a cell heated electrically to 520-570 K or (b) using fused electrolyte, of composition KF HF = 1 2, in a cell at 340-370 K which can be electrically or steam heated. Moissan, who first isolated fluorine in 1886, used a method very similar to (b) and it is this process which is commonly used in the laboratory and on an industrial scale today. There have been many cell designs but the cell is usually made from steel, or a copper-nickel alloy ( Monel metal). Steel or copper cathodes and specially made amorphous carbon anodes (to minimise attack by fluorine) are used. Hydrogen is formed at the cathode and fluorine at the anode, and the hydrogen fluoride content of the fused electrolyte is maintained by passing in... 

It is extensively used for making stainless steel and other corrosion-resistant alloys such as Invar(R), Monel(R), Inconel(R), and the Hastelloys(R). Tubing made of copper-nickel alloy is extensively used in making desalination plants for converting sea water into fresh water. 

TABLE 11.57 Type E Thermocouples Nickel-Chromium Alloy vs. Copper-Nickel Alloy Thermoelectric voltage in millivolts reference junction at 0°C. 

Copper nickel Copper-nickel alloy Copper-nickel alloys... 

Iron, steel, nickel, copper—nickel alloys, and Inconel Ni—Cr—Fe are satisfactory for dry or hot sulfur dioxide, but are readily corroded below the dew... 

Copper—Nickels. The copper—nickel alloy system is essentially single phase across its entire range. Alloys made from this system are easily fabricated by casting, forming, and welding. They are noted for excellent tarnishing and corrosion resistance. Commercial copper alloys extend from 5 to 40 wt % nickel. Monel is a nickel—copper alloy that is outside of this range and contains 29—53 wt % of copper. 

Properties of copper—nickel alloys are Hsted in Table 14. The alloys in the copper—nickel group have been successfully cast using the centrifugal, investment, permanent, and sand molding methods. The minimum tensile strengths on test bars cast in sand molds are 207—310 MPa (30,000—45,000 psi). 

Table 14. Properties of Copper-Nickel Alloys and Leaded Nickel Bronze and Brass...

Copper-nickel alloys up to 30% nickel 1 5 2 4 <400 3 < 750 Wronglit, cast, clad ... 

Figure 8.2 Corrosion rates of copper and copper-nickel alloys in a 50% caustic soda evaporator (Courtesy ofF. L. LaQue, Corrosion 10 391 1954.)...

Nickel is usually alloyed with elements including copper, chromium, molybdenum and then for strengthening and to improve corrosion resistance for specific applications. Nickel-copper alloys (and copper-nickel alloys see Section 53.5.4) are widely used for handling water. Pumps and valve bodies for fresh water, seawater and mildly acidic alkaline conditions are made from cast Ni-30% Cu type alloys. The wrought material is used for shafts and stems. In seawater contaminated with sulfide, these alloys are subject to pitting and corrosion fatigue. Ammonia contamination creates corrosion problems as for commercially pure nickel. 

Copper/nickel alloys Alloys containing 5-30% Ni, used mostly in the wrought condition have a very good combination of properties. For optimum corrosion resistance, additions of 0-5-2 0% each of Fe and Mn are made. 

Neutral and alkaline solutions Copper-base materials are resistant to alkaline solutions " over a wide range of conditions but may be appreciably attacked by strong solutions, particularly if hot. Copper/nickel alloys usually give the best results in alkaline solutions. Copper and copper alloys should be avoided if ammonia is present, owing to the danger of both general corrosion and, if components are under stress, stress corrosion. 

The effects on oxidation resistance of copper as a result of adding varying amounts of one or more of aluminium, beryllium, chromium, manganese, silicon, zirconium are described in a number of papers Other authors have investigated the oxidation of copper-zincand copper-nickel alloys , the oxidation of copper and copper-gold alloys in carbon dioxide at 1 000°C and the internal oxidation of various alloys ". ... 

Sneddon, A. D. and Kirkwood, D., Marine Fouling and Corrosion Interactions on Steels and Copper-Nickel Alloys, Proc. UK Corrosion 88 Conf., Inst. Corr. Sci. Tech. NACE (1988)... 

The advanced all-metallic catalysts are believed to be formed by bonding active copper-nickel alloys onto stainless steel wires. Under the scanning electron microscope, it appears that the surface area may be more than twenty times the geometric surface area (42) ... 

The hydrides of copper-nickel alloys have been studied by Baranowski and Majchrzak (25, 25a), who observed their existence up to a ratio Ni/Cu = 1. Figure 4 represents the lattice parameter of the alloys and their /3-phase hydrides as a function of the alloy content in nickel and copper. 

In Fig. 1 there is indicated the division of the nine outer orbitals into these two classes. It is assumed that electrons occupying orbitals of the first class (weak interatomic interactions) in an atom tend to remain unpaired (Hund s rule of maximum multiplicity), and that electrons occupying orbitals of the second class pair with similar electrons of adjacent atoms. Let us call these orbitals atomic orbitals and bond orbitals, respectively. In copper all of the atomic orbitals are occupied by pairs. In nickel, with ou = 0.61, there are 0.61 unpaired electrons in atomic orbitals, and in cobalt 1.71. (The deviation from unity of the difference between the values for cobalt and nickel may be the result of experimental error in the cobalt value, which is uncertain because of the magnetic hardness of this element.) This indicates that the energy diagram of Fig. 1 does not change very much from metal to metal. Substantiation of this is provided by the values of cra for copper-nickel alloys,12 which decrease linearly with mole fraction of copper from mole fraction 0.6 of copper, and by the related values for zinc-nickel and other alloys.13 The value a a = 2.61 would accordingly be expected for iron, if there were 2.61 or more d orbitals in the atomic orbital class. We conclude from the observed value [Pg.347]

Manganese-copper (-nickel) alloys are used as temperature-independent resistors. They are ubiquitous in electronics. 

Fig. 6. Activities of copper-nickel alloy catalysts for the hydrogenolysis of ethane to methane and the dehydrogenation of cyclohexane to benzene. The activities refer to reaction rates at 316° C. Ethane hydrogenolysis activities were obtained at ethane and hydrogen pressures of 0.030 and 0.20 atm., respectively. Cyclohexane dehydrogenation activities were obtained at cyclohexane and hydrogen pressures of 0.17 and 0.83 atm, respectively (74).

Summary of Kinetic Parameters for Ethane Hydrogenolysis on Copper-Nickel Alloys (74)... 

Evidence for a marked difference between the surface and bulk compositions of dilute copper-nickel alloys has been reported recently by a number of investigators (82, 87-90). Much of the experimental evidence comes from hydrogen adsorption data (74, 82, 87, 90). The conclusions of van der Plank and Sachtler were based on the premise that nickel chemisorbs hydrogen while copper does not (82, 87). The total adsorption of hydrogen at room temperature was taken as a measure of the amount of nickel in the surface. However, in hydrogen adsorption studies on the catalysts used to obtain the catalytic results in Fig. 6, the amount of adsorption on the copper catalyst, while small compared to the adsorption on nickel, is not negligible (74) However, the amount of strongly adsorbed... 

Fig. 7. Percentage d character of the metallic bond in copper-nickel alloys as a function of composition (74, 84).

Copper-nickel alloy films similarly deposited at high substrate temperatures and annealed in either hydrogen or deuterium were used to study the hydrogenation of buta-1,3-diene (119) and the exchange of cyclopentane with deuterium (120). Rates of buta-1,3-diene hydrogenation as a function of alloy composition resemble the pattern for butene-1 hy-... 

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