Corrosion Performance of Nano-ZrO₂ Modified Coatings in Hot Mixed Acid Solutions.

Wenhua Xu,En-Hou Han,Shuai Wang,Zhenyu Wang,Qian Liu

doi:10.3390/ma11060934

Wenhua Xu, En-Hou Han + Show 3 more

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https://doi.org/10.3390/ma11060934

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Abstract

A nano-ZrO2 modified coating system was prepared by incorporation of nano-ZrO2 concentrates into phenolic-epoxy resin. The corrosion performance of the coatings was evaluated in hot mixed acid solution, using electrochemical methods combined with surface characterization, and the effects of nano-ZrO2 content were specially focused on. The results showed that 1% and 3% nano-ZrO2 addition enhanced the corrosion resistance of the coatings, while 5% nano-ZrO2 addition declined it. The coating with 3% nano-ZrO2 presented the minimum amount of species diffusion, the lowest average roughness (5.94 nm), and the highest C/O ratio (4.55) and coating resistance, and it demonstrated the best corrosion performance among the coating specimens.

Highlights

The flue gas from oxy-fuels has higher levels of acid gases, mainly including SOx and NOx with smaller amounts of HF and HCl [1]
The corrosion protection characterizations for nano-ZrO2 -modified coatings were examined in mixed acid solution
Corrosion resistance was enhance for the coatings with 1% and 3% nano-ZrO2 contents, while it declined for the coating with 5% nano-ZrO2 content

Summary

Introduction

The flue gas from oxy-fuels has higher levels of acid gases, mainly including SOx and NOx with smaller amounts of HF and HCl [1]. The hot flue gases may be compressed and cooled to form mixed acid environments, which are mainly composed of highly concentrated H2 SO4 , HNO3 , HCl and HF. Organic coatings have been used to control the corrosion of steels in the highly acidic environment. Phenolic-epoxy resin is the most important and industrialized epoxy polymer and possesses excellent acid and alkali resistance [2,3]. It acts as a physical barrier layer between the metal substrate and solution to inhibit the permeation of water and aggressive ions [4]. Due to the presence of porosity [5]

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Results

Conclusion