Improvement of Wear Resistance and Mechanical Properties of Cu-Ni Alloy by Low Temperature Aluminizing

This study is dedicated to improving the wear resistance of Monel 400 superalloy, which has superior properties in terms of corrosion and oxidation resistance. Pack aluminizing was applied to Monel 400 alloy for 2, 4 hours duration and temperatures of 600 degrees C, 650 degrees C, 700 degrees C. XRD and SEM analyses revealed the presence of phase components such as Ni2Al3 and Ni3Al. While Ni2Al3 is more prevalent in the upper parts of the coating, Ni3Al phases are more dominant in the inner region due to the low Al content around the interface. Although all experiments were carried out without a protective environmental condition, only trace amounts of the oxide phase were detected on the surfaces of the alloy. In nanoindentation and microhardness tests, up to 6 times more hardness was achieved on the surface. The increase in hardness and elastic modulus improved the wear resistance of Monel 400, regardless of aluminizing temperature and time. In contrast to the very low friction resistance seen in the wear tests of Monel 400, the coatings gave much lower volume losses. Although the mechanical properties of the coatings are important parameters, it was observed that the coating thickness and structure were more effective in wear resistance.