Morphology and electrochemical behavior of Ag–Cu nanoparticle-doped amalgams

The aim of this study was to introduce Ag–Cu phase nanopowder as an additive to improve the corrosion behavior of dental amalgams. A novel Ag–Cu nanopowder was synthesized by the precipitation method. An amalgam alloy powder (World-Cap®) was added and mixed with 5 wt.% and 10 wt.% of Ag–Cu nanopowders, respectively, to form experimental amalgam alloy powders. The original alloy powder was used as a control. Alloy powders were examined using X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy and electron probe microanalysis. Amalgam disk specimens of metallurgically prepared were tested in 0.9% NaCl solution using electrochemical methods. The changes in the corrosion potential and anodic polarization characteristics were determined. Corrosion potential data were analyzed statistically (n = 3, analysis of variance, Tukey’s test, p < 0.05). The diameters of lamellar structure Ag–Cu nanoparticles were measured to be approximately 30 nm. The composition of the Ag–Cu nanoparticles determined by TEM–energy-dispersive spectroscopy was 56.28 at.% Ag–43.72 at.% Cu. A light-shaded phase was found mixing with dark Cu–Sn reaction particles in the reaction zones of Ag–Cu nanoparticle-doped amalgams. The Ag–Cu nanoparticle-doped amalgams exhibited zero current potentials more positive than the control (p < 0.05) and no current peak was observed at −325 mV that related to Ag–Hg phase and Cu6Sn5 phase in anodic polarization curves. The results indicated that the corrosion resistance of high-copper single-composition amalgam could be improved by Ag–Cu nanoparticle-doping.