Development of CNT mixed HVOF coating for water tube boiler material to improve the degradations

Abstract

In most of the thermal power plants, one of the vital components is boiler tube. In thermal power plants the down fall in profits due to hot corrosion, oxidation and erosion. In order to improve properties of the above said, the researchers working on the wide area of combating hot corrosion, erosion and oxidation of boiler tubes by using thermal spray coatings (HVOF) with the combination of carbon nanotubes (CNTs). The corrosion occurs, when the material exposed to open atmosphere it will get corroded. The oxidation occurs due to the material is exposed to high temperatures. Erosion occurs due the presence of unburnt particles striking at high velocity. There by the application of HVOF (High-Velocity Oxy-Fuel) coating playing a vital role in approaching using HVOF parameters such as speed, high temperature, oxygen with fuel flow and fuel ratio, powder flow rate. In the present studies the resistance improvement of corrosion, oxidation and erosion of the boiler tube material SA213 T11. The advantages of HVOF coatings with CNTs percentages like CNT 3%, 5%, 7%. are due to its low porosity, high dense coatings, more adhesive in nature and bond strength also more. The kinetics of hot corrosion, oxidation and erosion will be analysed by measuring weight gain after every cycle under thermogravimetric studies (1 h heating and 20 min cooling). The results will be achieved by using visual examination, and advanced microscopy like XRD and SEM/EDS analysis.