Table 7.
Corrosion properties of PU/ZnO composite.
| ZnO | PU Monomer | Ecorr(mV)(at Optimum Content) | Substrate | Protection Mechanism | Ref. | ||
|---|---|---|---|---|---|---|---|
| Nature | Used Content | Optimum Content | |||||
| Pristine | 0.1 wt.%, 1.0 wt.% |
0.1 wt.% | Not mentioned, commercial grade | … | Mild steel | (1) Improved barrier resistance and (2) reduced UV-degradation | [31] |
| Poly(o-toluidine) functionalized | 7.0 wt.%, 14.0 wt.% | 7.0 wt.% | Not mentioned, commercial grade | −669.5 | Carbon steel | (1) Passive layer formation, (2) synergistic effects of poly(o-Toluidine) and (3) coating porosity reduced by addition of ZnO | [34] |
| Amine functionalized |
1.0 wt.%, 2.0 wt.% | 2.0 wt.% | Polyol, diisocyanate | … | Mild steel | (1) Crosslinked structures formation, which ultimately improved barrier resistance | [35] |
| Pristine | 2.0 wt.%, 4.0 wt.%, 6.0 wt.% |
6.0 wt.% | Not mentioned, commercial grade | −692 | AISI 1018 carbon steel | (1) Improved hydrophobicity and (2) compactness of the coatings | [40] |
| Oleic acid functionalized | 0.1 wt.%, 0.3 wt.% |
0.3 wt.% | Not mentioned, commercial grade | −678 | Mild steel | (1) Filler acted to seal coatings pores and (2) improve the barrier protection | [60] |
| Pristine | 1.0 wt.%, 3.0 wt.%, 5.0 wt.% |
1.0 wt.%, 3.0 wt.% |
Not mentioned, commercial grade | … | Low carbon steel | (1) Chemical interaction between ZnO and polyurethane | [69] |
| Pristine | 0.1 wt.%, 2.0 wt.% |
2.0 wt.% | Not mentioned, commercial grade | … | Steel | (1) Improve barrier resistance | [79] |