Study of the corrosion properties in a hot forged Cu-Al-Ni alloy with added Cr

Abstract

Here, the corrosion properties of chromium (Cr) added to a copper-aluminum-nickel (Cu-Al-Ni) alloy were studied. Primarily, the alloy samples were prepared by increasing the percentages of Cr composition in the following series of 4%, 8% and 12% by keeping other alloying elements as constants. The alloy was made using the powder metallurgical technique. Consequently, hot forging was done on the sintered specimen. Both hypothetical and authentic densities were found for the hot forged samples which showed that the densities kept on increasing with the addition of Cr. The Cr embellishments were exposed using optical microscopy of varying magnifications. The corrosion properties achieved from the potentiostat showed that the corrosion resistance upsurges more than the other commercially available nickel-aluminum-bronze (NAB) alloys due to the Cr embellishments. The corroded surface was then investigated using scanning electron microscopy (SEM) which disclosed the formation of different κ phases along with an α matrix and other intermetallic phases in the present alloy. Furthermore, hardness tests were taken and these established that the hardness increases with Cr accompaniments. Thus, the present alloy can be endorsed as a novel material (Cu-Al-Ni-Cr) in the propellers of ships in which both hardness and corrosion resistant are obligatory.