A green and effective corrosion inhibitor of functionalized carbon dots

In this work, a green and effective corrosion inhibitor of functionalized carbon dots(FCDs) was synthesized by the conjugation of imidazole and citric acid carbon dots(CA-CDs). The corrosion inhibition behavior of FCDs for Q235 steel in 1 M HCl solution was systematically investigated by electrochemical analysis, corrosion morphology and adsorption isotherm. The electrochemical results implied that the as-prepared FCDs inhibitor could effectively suppress the corrosion of Q235 steel in 1 M HCl solution. At the same time, the inhibition efficiency of steel in 1 M HCl solution was more than 90% when the inhibitor concentration exceeded 100 mg/L. This excellent property was attributed to the coverage of adsorption film on the steel surface, which conformed to the Langmuir adsorption model. In addition, the analysis of adsorption isotherm displayed that the adsorption mechanism was the physicochemical interaction at the steel/solution interface.

Study on self-healing and corrosion resistance behaviors of functionalized carbon dot-intercalated graphene-based waterborne epoxy coating

Functionalized carbon dots(CDs)obtained from citric acid derivative were selected as intercalatorto modify graphene and then dispersed into epoxy matrix to prepare CDs modified graphene/epoxy(CDs-G/EP)coatings.Meanwhile,their microstructure,self-healing and corro sion resistance behaviors were analyzed deeply.Structural characterizations indicated the formation of"π-π"interaction between functionalized carbon dots and graphene.By observation,the dispersion and interface compatibility of graphene were greatly enhanced by CDs.The change rules of electrochemistry results implied that the addition of 0.5 wt.%CDs-G in EP coating(CDs-G0.5%/EP)demonstrated a superior protective property on steel,which was attributed to the physical barrier of highly dispersed graphene and the self-healing ability of CDs.After 50 days immersion,the oxygen permeability coefficient and water absorption of CDs-G0.5%/EP coating were only 4.27×10^(-13)cm^(3)cm cm^(-2)s^(-1)Pa^(-1) and 4.4%,respectively.

Evaluation of the inhibition behavior of carbon dots on carbon steel in HCl and NaCl solutions

An eco-friendly and effective corrosion inhibitor(N-CDs)was acquired by hydrothermal method in methacrylic acid and ethyl(methyl)amine precursors.Afterwards,the weight loss and electrochemistry measurement were chosen to appraise the corrosion inhibition behavior of as-prepared N-CDs for Q235 steel in Cl-contained solutions.The change rules of EIS and Tafel data displayed that the as-prepared N-CDs revealed a high-efficiency protection for steel in all test environments.Meanwhile,the inhibition efficiency of steel reached up to 93.93%(1 M HCl)and 88.96%(3.5 wt%Na Cl)at 200 mg/L of N-CDs.Furthermore,the N-CDs could form the adsorption film on steel surface to avoid the strong attack of Cl-.By analysis,the adsorption mechanism of as-prepared N-CDs on steel surface was physicochemical interaction,which strictly complied with the Langmuir adsorption model in both solutions.

Understanding corrosion and tribology behaviors of VN and VCN coatings in seawater

VN and VCN coatings were prepared using multi-arc ion plating technique on 316L stainless steel and single silicon sub-strates.Microstructures,mechanical performances,corrosion behaviors and tribology properties of VN and VCN coatings in the atmosphere,distilled water and seawater were contrastively tested.It was confirmed that the VCN coating had a typi-cal nanocystallite/amorphous structure.Moreover,the hardness increased from 30.5 to 36.5 GPa and the corrosion current density decreased from 2.16×10^(−6) to 0.82×10^(−6)A cm^(−2) after carbon was doped into the VN coating.Compared with the VN coating,the VCN coating had the lowest friction coefficient of 0.26 and wear rate of 0.68×10^(−6)mm^(3)Nm^(−1) in seawater,which could be ascribed to the lubrication of graphitization transfer film and improvement of the comprehensive performance.