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The effect of the addition of different concentrations of Cu2+, Fe2+, and Fe3+ on the micromorphology and crystalline structure of CaCO3 fouling was studied using the VHX-500FE digital microscope and X-ray diffraction. Results indicate that the fouling morphology becomes stubby and forms a cluster and the fouling color deepens with the increase in the concentration of metal ions. Furthermore, the relative content of aragonite increases and that of calcite decreases. Fe2+ plays a more important role in the inhibition of calcite than Fe3+ when scaling occurs in the boiling system under the condition of atmospheric environment. The reason may be that O2 participates in the inhibition process. Fe2+ and Fe3+ promote atomic transition and crystal defects, and this condition changes the absorption wavelength of fouling. Carbon steel and copper samples were immersed in test solution for 28 h as a comparative experiment. This experiment indicates that corrosion may release metal ions, which further affect the fouling morphology and phase component content in the long-term fouling process. In conclusion, fouling weight method for measuring anti-fouling property can only be used to compare materials with similar anti-corrosion property. [ABSTRACT FROM AUTHOR]

Abstract: Fouling adhering experiments on AISI 304 stainless steel surfaces with different roughness had been performed in boiling supersaturated calcium bicarbonate solution. The effect of surface roughness on adhesion of fouling is limited, and the adhesion of fouling does not have a simple linear relationship with the surface roughness of samples. The surface with roughness in middle is more easily induced to form “transitional interface” which connects the fouling and matrix surface. It is also found that the crystalline types of fouling are changed in the fouling process due to the variation of metallic ions in reaction solution. [Copyright &y& Elsevier]