Influence of Mg²⁺ and SO₄^2- Concentration on the Formation of Calcareous Scales on Electrode Surface

Artificial seawater was used as the test medium, B30 copper-nickel alloy was used as the working electrode, and scanning electron microscopy (SEM), X-ray diffraction, polarization curve, and electrochemical impedance test were used to study the effect of changes in Mg²⁺ and SO₄^2- content in artificial seawater on the formation of calcium deposits on the surface of the B30 copper-nickel alloy electrode with cathodic protection. The results show that the increase of Mg²⁺ in the solution caused changes of crystal structure and surface morphology of the calcareous deposits, and also inhibited the nucleation and crystal growth of the calcareous deposits. While the increase of SO₄^2- caused the change of surface morphology of calcareous deposits, which would inhibit the nucleation and crystal growth of calcareous deposits, but promoted the formation of Mg(OH)₂ deposits.