Effect of Composition and Thickness on the Hardness and Scratch Resistance of Copper and Copper Alloy Coatings

Coatings are extensively used as corrosion resistance, wear resistance, and antibacterial surfaces. Copper and copper alloys are among the most widely applied coating materials for industrial and medical applications. In this work, mechanical assessment of Cu, Cu 4%Sn, Cu 17%Ni 10%Zn (German Silver), and Cu 17%Al 1%Fe coatings deposited on stainless steel 316L substrates using twin wire arc thermal spraying is studied experimentally. Microstructure, hardness, and scratch resistance were studied for all coated samples. The effects of having different coating compositions on the mechanical properties are analyzed. The effect of the coatings thickness is also investigated for Cu 17%Ni 10%Zn and Cu 17%Al 1%Fe coatings with different thicknesses between 200 and 400μm. The study focused on how the scratch resistance increases with increasing the coating thickness on the expense of the adhesion. A comparison of the coating hardness profile between different copper and copper alloy compositions was presented. An interesting observation was that even though scratch hardness increases with the coating thickness, hardness decreases as a function of the distance from the interface.