Evaluation of Microstructural Features of HVOF Sprayed Ni–20Al Coatings
The present study evaluates the microstructural features of high velocity oxy-fuel (HVOF) sprayed Ni–20Al coatings with liquefied petroleum gas (LPG) as fuel. The Ni–20Al coatings are commonly used for bond coat applications and as high temperature oxidation resistant coating. The quality of the deposited coating has been evaluated in terms of porosity, oxide content, surface roughness, micro-hardness, composition and morphology (surface and cross-sectional). The results indicate that, it is possible to develop dense Ni–20Al coatings with low oxide and porosity content along with high surface roughness using HVOF technology. Importantly, HVOF sprayed Ni–20Al coatings show better quality as compared to air plasma spray and can be used as an alternative to VPS in terms of quality to cost ratio for bond coat applications.
KeywordsHVOF Ni–20Al Coatings Bond coats Surface roughness
The authors would like to thank Gujarat Council on Science and Technology (GUJCOST) for providing financial assistance through MRP scheme. Authors also wish to thank Dr. Mukul Gupta of UGC-DAE Consortium for Scientific Research, Indore for performing XRD analysis and Mr. Ragesh Bateriwala, Keepsake Engineering Consultancy Pvt. Limited, Ahmedabad, Gujarat, for providing the HVOF facility.
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