Experimental study on corrosion-fouling relationship of Ni-W-P composite coating surface of heat exchanger

Abstract

The ternary Ni-W-P coating was prepared on mild steel (1015) and the corrosion-fouling relationship was investigated. Meantime, the Ni-W-P coatings were characterized in terms of their properties and surface morphology by means of scanning electron microscope (SEM), x-ray diffraction (XRD) and electrochemical station. The result of fouling experiment shows that the Ni-W-P coating has better anti-fouling property than the uncoated mild steel surface. Additionally, both of the samples with or without Ni-W-P coating contain formation of calcites and aragonites in the same condition in the study. The uncoated mild steel adheres more aragonites while more calcites deposits on the surface of Ni-W-P coating. The corrosion experiment shows that due to the less corrosion cracks and pits producing, the Ni-W-P coating surface in different immersion stage inhibits the adhesion of fouling effectively compared with the uncoated mild steel surface. Furthermore, the phase structures of fouling are affected by the corrosion of samples with or without Ni-W-P coating differently due to the metal ions generated by corrosion. The work provides techniques that the corrosion resistance and anti-fouling performance should be combined to use when we apply surface modification in the fields of heat transfer.

Study on Heat Transfer Performance and Anti-Fouling Mechanism of Ternary Ni-W-P Coating

“…Therefore, there are not only calcium carbonate fouling but also iron rust formed on the substrate surface. The result conforms to our previous studies [10,13] and proves that Ni-W-P has an admirable effect on anti-fouling performance. After calculating the mass change of the fouled specimens, it was found that there is no obvious rule between the mass change and the W content in the coating, while the certainty is that the mass gain of fouling on all the coated specimen is less than that of the bare substrate surface in the same period.…”

“…It can be seen from Figure 1 that the fouling of calcium carbonate Since the 1980s, electroless plating has been treated as an operational technology of the surface modification, attracting widespread attention [4][5][6][7][8]. The results prove that electroless Ni-P-based coating is an advantageous method for fouling inhibition [9][10][11][12][13]. The mass gain method [10,11,14], the calcium ion loss method [12], and the fouling resistance method [15] were commonly used for measuring the deposition process of calcium carbonate fouling on materials surface.…”

“…The "transition interface" consists of corrosion or oxidation, and the lattice of the "transition interface" layer can be easily matched with the lattice of fouling. Therefore, the adhesion of fouling on the corrosion interface seems to be easier [13,16,17]. Simultaneously, compared with uncoated pipe, the tube with electroless coating can significantly improve the property of condensation heat transfer, showing the coexistence of dropwise and filmwise on most working conditions [18,19].…”

Synergistic Effect of Composite V2O5/Ca0.17V2O5 Film Electrodes as High-Performance Cathodes of SIBs

“…That indicates that the V 2 O 5 possesses a better corrosion resistance, and the V 2 O 5 /Ca 0.17 V 2 O 5 has a higher charge transfer rate. , Meanwhile, the corrosion potential ( E corr ) can represent thermodynamic tendency to oxidation or passivation. , The E corr of V 2 O 5 /Ca 0.17 V 2 O 5 is −0.022 V, which is higher than that of V 2 O 5 (−0.047 V). The higher E corr means the V 2 O 5 /Ca 0.17 V 2 O 5 film electrode has a lower thermodynamic tendency to oxidation or passivation, which can be ascribed to the different chemical composition and microstructure. , To understand the electrode reaction kinetics of films, EIS measurements are characterized in Figure b. The Nyquist plots consist of an intercept at a high frequency and a sloping line at a low frequency.…”

Effects of heat treatment on microstructure and properties of Fe-based amorphous composite coatings

“…Figure 6(b) is the Tafel polarisation curves of the coatings before and after heat treatment, the relevant parameters are determined using the Tafel extrapolation method [37], as shown in Table 3. In general, high corrosion potential ( E corr ) and low corrosion current density ( I corr ) indicate that the material has higher chemical stability and lower corrosion tendency [38,39]. It can be seen that the E corr of all coatings after heat treatment slightly increases, and the I corr decreases.…”