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| Abstract No.: |
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| Title: |
Influence of oxy-fuel ratio on particle behavior of HVOF sprayed NiCrAlY coating using LPG as fuel
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| Authors: |
Girish Rayudu* / Sharvan Coating Services, India
A S Khanna / Indian Institute of Technology, Bombay, India
S C Modi/ Metallizing Equipment Co Pvt Ltd, India
Karunanidhi Nune/ Sharvan Coating Services, India
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| Abstract: |
Thermally sprayed NiCrAlY coatings are deposited using Vacuum Plasma Spray (VPS) process. Because of the vacuum the coating is dense and oxide free. However the newer coating system used in the present study is a High Velocity Oxy Fuel (HVOF) system and LPG was used as fuel. The system under study certainly offers a cost advantage over the VPS system as the time involved is less and the operating cost being lower. The desired coating properties are achieved because of higher particle velocity and sufficient particle temperature. Due to high kinetic energy, the particles flatten in plastic state; hence the resultant coating is dense with lower oxide content. However in HVOF the coating properties are sensitive to variation in oxy-fuel ratios. An attempt has been made to understand the variation in the characteristics and the phase composition of HVOF sprayed NiCrAlY with the change in oxy-fuel ratio. Simultaneously the particle dynamics were also observed for different oxy-fuel ratios. The coatings were examined using metallography, SEM, EDAX and XRD techniques. The present work focuses on the influence of oxy-fuel ratio on morphology, microstructure, porosity, surface roughness and micro hardness with respect to particle behavior and the transformations that take place during HVOF spray.
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