The copper-nickel system offers a better dental alloy-base than the Ni-Co system due to the lower melting ranges of its components. The Cu-Ni system was further developed by the addition of Al and Cr to strengthen the alloys and render them resistant to corrosion. Corrosion and mechanical characteristics of the components of Cu-Ni-Al-Cr system were reported previously. Four alloys were selected as promising. This report addresses the metallographic microstructure as well as the quantitative chemical analyses of these four alloys. Each of the alloys depicted a cored structure in a matrix where the core is biphasic. Quantitative chemical analyses showed a matrix rich in Ni and Cr for alloys 1 and 3, and rich in Cu and Ni for alloys 2 and 4. The core was quite rich in Cr for alloys 1, 2, and 3 and is nearly pure Cr in alloy 4. Matrix phase for alloys 1, 2 and 3 possessed adequate Cr to be resistant to corrosion under oral environment.

Saudi Dental Journal 1993;5(3):106-113.