Incorporation of boron nitride nanosheets in zinc phosphate coatings on mild steel to enhance corrosion resistance

Thermally Conductive Anticorrosive Epoxy Nanocomposites with Tannic Acid-Modified Boron Nitride Nanosheets

“…When the contents of M-BNNS are 15 and 20 wt %, the Q coat value shows an upward trend and it increases significantly compared with EP coating, indicating that the penetration of corrosion solutions is more serious in these two composite coatings . Interestingly, the R coat value of 15%M-BNNS@EP and 20%M-BNNS@EP coating slightly increased and Q coat value slightly decreased after 120 h immersion, which may be attributed to the fact that the highest metal oxide passivation film obtained at this time played a certain role in corrosion protection …”

“…With the increase of the M-BNNS content, it does not have a positive impact on the corrosion resistance of the composite coating. When the mass content of M-BNNS is 15%, it can be seen from Figure b that many paths are formed between the boron nitride fillers (corresponding to SEM Figure g), which promote the electron transfer to a certain extent . As the boron nitride content continues to increase to 20%, BNNS are folded, piled up, and agglomerated in the EP matrix (corresponding to SEM Figure h), causing interface defects between M-BNNS and EP, and the corrosion solution penetrates into the metal plate, resulting in a decrease in the corrosion resistance of the coating .…”

“…100 Interestingly, the R coat value of 15%M-BNNS@EP and 20%M-BNNS@EP coating slightly increased and Q coat value slightly decreased after 120 h immersion, which may be attributed to the fact that the highest metal oxide passivation film obtained at this time played a certain role in corrosion protection. 86 The Tafel spectra of different coatings after immersed in 3.5 wt % NaCl corrosion solution for 120 h were also tested and shown in Figure 8a. The values of E corr and I corr obtained by the Tafel extrapolation method are listed in Table 3.…”

Niobium- and titanium-based coating for the protection of carbon steel SAE 1020 against corrosion

“…The value for n varies between 0 and 1, when n = 1, it represents a pure capacitive behavior, while, when n = 0, it represents a pure resistive behavior (Cui et al, 2017a;Liu et al, 2021). The magnitude of the value of n for the coated sample is similar to a zinc phosphate conversion coating on carbon steel SAE 1020 studied by Huang et al (2019) and to a europium oxide-based conversion coating studied by Mofidabadi et al (2021). The reduction in the value of n for the coated sample suggests a coating with a rough, heterogenous surface, in contrast to the smoother, more homogenous surface of the bare material, evidenced by a higher value of n. These results can be verified (Mofidabadi et al, 2021).…”

BiVO4–TiO2 Composite-Based Zinc Phosphate Coating for High NIR Reflectance and Sustainable Energy-Saving Applications

“…As a result, the dissolution of the zinc coating decreases and the formation rate of hopeite crystals increases. When the BiVO 4 –TiO 2 composite surpasses the optimum level in the phosphating bath, the ZP/0.5BiVO 4 –TiO 2 coating becomes nonuniform and the degree of crystalline coverage diminishes as the surplus composite in the phosphating bath causes redissolution (excess concentration of the composite on phosphate coating decreases the surface active site for new hopeite crystal nucleation, and in that way the dissolution of phosphate coating can take place). − From these observations, it can be concluded that incorporating the optimum amount of BiVO 4 –TiO 2 composite in phosphate coating can change the kinetics of phosphate crystallization reorganization …”