On the Distinctive Hardness, Anti-Corrosion Properties and Mechanisms of Flame-Deposited Carbon Coating with a Hierarchical Structure in Contrast to a Graphene Layer via Chemical Vapor Deposition

Abstract

Two carbonaceous (amorphous carbon and graphene) coatings were catalytically grown on bulk Ni plates. It was found that the flame-deposited carbon (FDC) layers exhibited a unique hierarchical structure with the formation of FDC/Ni nano-interlocking interface. The effect of the flame coating time on its corrosion protective efficiency (PE) was studied and compared with that of graphene coating produced via chemical vapor deposition. The FDC grown for 10 min exhibited a PE of 92.7%, which was much greater than that of the graphene coating (75.6%). The anti-corrosive mechanisms of both coatings were revealed and compared. For graphene coatings, the higher reaction temperature than that for FDC resulted in large grain boundaries inherent in the coating. Such boundaries were weak points and easily initiated grain boundary corrosion. In contrast, corrosion started at only certain local defects in FDC layers, whose unique interface structure likely promoted its PE as well. Moreover, after the coating process, the hardness of FDC-coated Ni remained almost unchanged, in contrast to that of graphene-coated samples (reduced by ~30%). This is suggested to be related to the crystal structure evolution of the Ni substrate caused by the heat treatment accompanying the coating process.

Incorporation of Graphene Oxide Modified with Polyamide Curing Agent into the Epoxy–Zinc Composite Coating for Promoting Its Corrosion Resistance

“…This indicates the increase in the interlayer spacing of GO, confirming the intercalation of PA 651 and the presence of functional groups in PGO. Similar to other research on GO based carbon materials [2][3][4], two strong bands could be observed in the Raman spectra of both GO and PGO (Figure 2b). After the modification of GO with the polyamide, the D (1349 cm −1 ) and G bands (1597 cm −1 ) moved to 1329 cm −1 and 1596 cm −1 , respectively, which indicated a certain charge transfer between the polyamide and GO.…”

“…Coatings are often unitized to protect metals from corrosion [1][2][3][4]. Among the various coatings, Zn-rich polymer composite paint is a widely applied type of coating due to the effect of the Zn particles, which work as anodes to provide cathodic protection for metal substrates [1,[5][6][7][8].…”

Improving the Corrosion Resistance of Zn-Rich Epoxy Coating with Three-Dimensional Porous Graphene

“…The large size and unique spatial structure of the 3DG fragments are expected to not only alleviate the re-stack of graphene sheets in the polymer matrix, but also favor the formation of the electric conductive path between Zn micro-flakes in the ZRE coatings, which helps to fully exert their cathodic protection function. Similar to the research on the graphene deposited on catalytic metal substrates in the literature [6,28], two strong peaks for the G band at 1576.7 cm −1 and the 2D band at 2700 cm −1 , together with a very weak peak for the D band around 1357 cm −1 , could be observed in the Raman spectrum of 3DG (Figure 3). As the D band refers to the disorder carbon Similar to the research on the graphene deposited on catalytic metal substrates in the literature [6,28], two strong peaks for the G band at 1576.7 cm −1 and the 2D band at 2700 cm −1 , together with a very weak peak for the D band around 1357 cm −1 , could be observed in the Raman spectrum of 3DG (Figure 3).…”

“…Similar to the research on the graphene deposited on catalytic metal substrates in the literature [6,28], two strong peaks for the G band at 1576.7 cm −1 and the 2D band at 2700 cm −1 , together with a very weak peak for the D band around 1357 cm −1 , could be observed in the Raman spectrum of 3DG (Figure 3). As the D band refers to the disorder carbon Similar to the research on the graphene deposited on catalytic metal substrates in the literature [6,28], two strong peaks for the G band at 1576.7 cm −1 and the 2D band at 2700 cm −1 , together with a very weak peak for the D band around 1357 cm −1 , could be observed in the Raman spectrum of 3DG (Figure 3). As the D band refers to the disorder carbon structure, and the relative intensities I D /I G could be used to evaluate the defect degree of carbonaceous structure, the Raman spectrum of 3DG confirms its high crystalline structure.…”

“…Moreover, the intensity ratio (I 2D /I G ) of 3DG is 0.66, which is much less than 1, implying its multi-layered structure [6,7,29]. Similar to the research on the graphene deposited on catalytic metal substrates in the literature [6,28], two strong peaks for the G band at 1576.7 cm −1 and the 2D band at 2700 cm −1 , together with a very weak peak for the D band around 1357 cm −1 , could be observed in the Raman spectrum of 3DG (Figure 3). As the D band refers to the disorder carbon structure, and the relative intensities ID/IG could be used to evaluate the defect degree of carbonaceous structure, the Raman spectrum of 3DG confirms its high crystalline structure.…”