The hardness and wear behavior properties of two C 18000 copper alloys with variations in Ni, Si, and Cr concentrations, both within the range of C18000 chemical analysis standard, were studied after the alloy samples had been prepared by melting and casting in sand molds and then heat-treated in solution using two-stage aging for different heating time periods. The results obtained from sample sets of the aforementioned two alloys, and , show that the alloy , with slightly higher Si and Ni and lower Cr concentrations than the alloy , produced significantly higher hardness values and wear resistance than the alloy . Optical and electron microscopy microstructure studies of representative samples revealed a copper matrix containing nickel and silicon in solution and precipitates of chromium and nickel silicides. By studying the wear surfaces and debris of the former samples with electron microscopy, different types of wear mechanisms including adhesive, abrasive, oxidation, and repeated-cycle deformation were found. The wear behavior was expressed as mass weight loss, which correspondingly shows a typical inverse relationship with the hardness values for both the and alloy groups.

Through testing under synthetic sea water, seven different copper alloys, namely naval brass and Cu27Zn2.6Pb alloys prepared by extrusion, from squeeze casting, naval brass and aluminium bronze, annealed naval brass and forged aluminium-silicon alloy, were tested in terms of their corrosion resistance, aiming to compare the corresponding behaviour of alloys produced by different metallurgical processes. The corresponding anodic polarisation curves as well as the chemical analysis and the metallurgical structure are shown. The results show a corrosion resistance, in decreasing order of: forged aluminium-silicon bronze, squeeze cast aluminium bronze, annealed naval brass, squeeze-cast naval brass, extruded naval brass, and finally extruded Cu27Zn2.6Pb alloy, demonstrating the role that the processing of a material plays in its final corrosion properties.

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