High-Temperature Corrosion Behaviour of CNT-reinforced Zirconium Yttrium Coatings on Boiler Tube Steel in Coal-Fired Boi
- PDF / 1,894,422 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 104 Downloads / 185 Views
TECHNICAL ARTICLE—PEER-REVIEWED
High-Temperature Corrosion Behaviour of CNT-reinforced Zirconium Yttrium Coatings on Boiler Tube Steel in Coal-Fired Boiler of Thermal Power Plant Sandeep Kumar . Rakesh Bhatia . Hazoor Singh
Submitted: 25 June 2020 / in revised form: 8 September 2020 ASM International 2020
Abstract Corrosion behaviour of carbon nanotubes (CNT)-reinforced zirconium yttrium coatings at high temperature under cyclic thermal loading has been investigated in actual coal-fired boiler environment of thermal power plant. The amount of CNT was varied from 0.5 to 6 wt.%, and the coating was developed by the plasma spray technique. The comparative effects of variation in CNT content on hot corrosion behaviour were studied by weight change measurements. The corroded products were then analysed with XRD, FE-SEM with EDAX and X-sectional analysis techniques. The results revealed that the variation in CNT percentile enhances the hot corrosion resistance of boiler steel in actual boiler environment at elevated temperature. The reinforced coatings showed the lower weight gain measurements with the formation of protective scale of oxides during the experiment. Corrosion rate was observed to be reduced with the increased content of CNT in the coating composite. Keywords Hot corrosion CNT T-91 boiler steel Thermal power plant
S. Kumar (&) Mechanical Engineering Department, Guru Kashi University, Talwandi Sabo, Punjab, India e-mail: [email protected] R. Bhatia H. Singh Mechanical Engineering Section, Yadavindra College of Engineering, Talwandi Sabo, Punjab, India
Introduction The materials used at high-temperature applications are protected effectively by thermal barrier coatings [1, 2]. Thermal barrier coating materials must have significant thickness, lower in porosity, good surface roughness and high hardness, not only to withstand load-caring capacity but also to resist high-temperature erosion-corrosion. With high thermal stability, high hardness and low thermal conductivity ceramic materials are ideal for high-temperature applications [3–5]. The thermal barrier coating is having porous structure with microcracks and voids which may lead to an increased value of porosity [6, 7]. The corroded species and chemicals attack the steel through these pores [8–11]. The porosity of thermal barrier coating lowers the mechanical and microstructural properties of steel and hence downgrades the heat resisting capacity under high-temperature erosion-corrosion environment. So for the present scenario, researchers were trying to improve the properties and performance of thermal barrier coating by the addition of composite materials to the coatings. The yttria-stabilized zirconia (YSZ)-reinforced silicon carbide coatings exhibit better hardness with improved fracture strength than the conventional YSZ coatings on steel [12–14]. For structural applications, the durability of ceramic composites is enhanced by high hardness reinforcements [15]. Nanomaterials, i.e. carbon nanotubes (CNT), are having extraordin
Data Loading...
