Characterization Evaluation of Plasma-Sprayed CNT Reinforced Inconel718 Coatings on T91 Boiler Steels

Background: Plasma spraying, a surface modification technology, was performed to deposit Inconel718 and CNT-reinforced Inconel718 coatings on T91 boiler steels. The coatings were expected to improve the corrosion resistance of boiler steels, thus extending their service life at high temperatures. The deposited coatings were characterized in terms of microstructure, porosity, microhardness, SEM, and EDAX. Materials and Methods: Through this representative patent method, the deposited coatings brought about a considerable porosity reduction and had an impact on the microhardness. Moreover, it was observed that in Inconel718 coatings reinforced by CNTs, the carbon nanotubes were homogeneously distributed, increasing the uniformity of the coatings, as well as their strength. Additionally, the uniformity of the coating represents a testimony to its enhanced resistance to corrosion. Results: Based on the testing results, the thickness of the coating achieved was 215 ± 5 microns. The addition of CNTs to Inconel718 coatings had reduced the porosity of the coatings to 2.2% from 3.8% and improved the microhardness of the coatings to 968Hv from 679 Hv. This further improved the corrosion protection of T91 boiler steels. A uniform distribution of CNTs throughout the coating matrix was observed. Conclusion: Therefore, based on the analysis conducted, it possible to ascertain that the plasmasprayed CNT-reinforced Inconel718 coatings have a veritable impact on promoting the corrosion resistance of boiler steels. It follows that such technology reduces the dormant functionality of boilers in industries and facilitates efficient service and industry development for a variety of industries.