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| Abstract No.: |
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Scheduled at:
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Thursday, September 29, 2011, Saal C2.1 2:50 PM
Corrosion Protection 2
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| Title: |
Performance of HVOF and cold sprayed Ni-20Cr coatings in aggressive molten salt environment at 900°C under cyclic conditions
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| Authors: |
Niraj Bala / Baba Banda Singh Bahadur Engineering College Fatehgarh Sahib., India
Harpreet Singh* / IITR, Rupnagar, India
Satya Prakash/ IITR, Roorkee, India
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| Abstract: |
Nickel-chromium alloys have been used as coatings to deal with oxidation environments at high temperature. The present work is a comparative study of HVOF and cold sprayed Ni-20Cr coating on a boiler steel (SAE 213-T22) in a molten salt environment of Na2SO4-60%V2O5 at 900°C under cyclic conditions. The weight change technique was used to establish the kinetics of corrosion. X-ray diffraction, surface and cross-sectional FE-SEM/EDS techniques were used to analyse the corrosion products. The hot corrosion resistance of cold sprayed Ni-20Cr coating was better than HVOF sprayed counterpart. The hot corrosion resistance of both coatings may be attributed to the formation of oxides and spinels of nickel and chromium. These oxides might have blocked the pores and splat boundaries, and acted as diffusion barriers to the inward diffusion of oxidizing species. Based upon the overall results and subsequent analysis of hot-corrosion data the cold spray process may be recommended as a better choice for the deposition of the Ni-20Cr coating on Mo-containing T22 steel in comparison with the HVOF spray process for hot corrosion protection.
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