The properties of MWCNT/polyurethane conductive composite coating prepared by electrostatic spraying

To improve the corrosion resistance of the steel ground grid and its discharge property, in the present work, multi-walled carbon nanotube (MWCNT)/polyurethane (PU) composite coatings were prepared on the steel surface utilizing a novel electrostatic spraying method. The MWCNT/PU composite coatings fabricated via the electrostatic spraying route were found to have the advantage that the CNTs were uniformly dispersed in the matrix. The effect of the morphology and the content of CNTs on the resistivity of the steel ground grid, its corrosion resistance in the soil, and the contact resistance between the coating and the soil, were systematically investigated. When the content of MWCNTs was 6 wt.%, the resistivity of the composite coating reached a low value of 9.2 × 10−2 Ω m. Moreover, a low coating/soil contact resistance of 10.6 Ω m was obtained in the coating with 6 wt.% MWCNTs, smaller than that (15.4 Ω m) of neat carbon steel. In addition, the corrosion resistance of the MWCNT/PU coated carbon steel ground grid was improved apparently. Its resistance was more than 8 times higher than that of the neat steel. These values met the requirements of ground grid.