Copper Nickel Alloy Research Paper

History of Copper-Nickel Alloys

Copper-nickel is an alloy of copper that contains nickel. The percentage of nickel in copper-nickel alloy can be vary depending on the applications. The use of nickel in coinage was employed for about 2000 years ago by many countries even though nickel metal was only discovered by scientists later on. This statement can be confirmed by the discovery of coins from antique that contain approximately 10% to 15% of nickel element.

The oldest copper-nickel coin comes from the period BC 235. This coin was found in Bactria and has a composition that is very close to the old-time German 50-Pfennig.

German 50-Pfenning

Copper-nickel alloy was known as “white copper” to the Chinese since about the third century

This phenomenon was first published in 1895 in a paper of the Physikalisch-Technischen Reichsanstalt in Berlin on ‘Electrical properties of Copper-Nickel alloy’. Besides, the additions of iron to copper-nickel alloy in order to increase the resistance of copper-nickel alloy to erosion corrosion was discovered in year 1925.

Introduction of Copper-Nickel Alloys

Copper-nickel alloys are the mixture of copper and nickel with or without other elements. For example, if zinc is present, zinc contain may not be more than 1%. If elements other than copper and nickel are present in the alloy, copper will be the major component followed by nickel and then other element.

Copper and nickel are adjacent to one another in the periodic system of elements with atomic number of 29 and 28 respectively. The atomic weights of copper and nickel are 63.54 and 68.71 respectively. The two elements are closely related and are completely miscible in both the liquid and solid

The addition of nickel to copper-nickel alloys makes the color to become lighter. Little amount of nickel alloy cast a yellow-pink hue. Alloys containing up to 15% of nickel and above have a silvery-white appearance similar to stainless steel and are used in coinage. The alloys can turn various colors in seawater depending on the iron content, immersion time and seawater condition such as golden brown, dark brown and green colour.

The physical properties of copper-nickel alloy vary from alloy to alloy with different composition. Melting range temperatures, electrical resistivity and modulus of elasticity increase when the nickel content increase while thermal conductivity decreases when nickel content increases.

Corrosion resistance

Copper-Nickel alloys are the most resistant toward corrosion among all the alloys. They are resistant to moisture, non-oxidising acids, alkalis and salt solutions, organic acids and to gases such as oxygen, chlorine, hydrogen chloride, hydrogen fluoride, sulphur dioxide and carbon dioxide. Stress corrosion cracking is seldom observed in copper-nickel alloy and the tendency to selective corrosion is extremely