Corrosion behavior and mechanism of copper soaked in ammonia water

The corrosion behavior and mechanism of Cu soaked in ammonia water were studied at 30°C using open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and polarization curve, combined with optical microscopy, scanning electron microscopy (SEM), X-ray powder diffractometer (XRD), energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) and other analytical techniques. The findings demonstrated that when the concentration of ammonia water increased from 0.1 wt.% to 1.0 wt.%, the corrosion rate of Cu increased from 21.9 μA/cm
2
to 32.3 μA/cm
2
, and when the temperature of ammonia water increases from 30°C to 50°C, the corrosion rate of Cu increased from 30.2 μA/cm
2
to 68.5 μA/cm
2
. The surface of Cu had obvious oxidation discoloration in ammonia water, the corrosion reactions of Cu in ammonia water involved oxidation-reduction and complexation process, and ammonia formed copper-ammonia complexes with Cu (I) and Cu (II), destroying the Cu surface protective film and accelerating oxidation corrosion. In ammonia water, the corrosion products of Cu were Cu
2
O, CuO, Cu(OH)
2
and copper-ammonia complexes.