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| Abstract No.: |
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Scheduled at:
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Tuesday, June 03, 2008, Room 04 11:30 AM
Corrosion Protection 2
Corrosion protection through thermal sprayed coatings including cathodic and high temperature corrosion, coating of large areas for offshore facilities and comparable applications
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| Title: |
Effect of Al on the performance of Ni-based PTA coatings
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| Authors: |
Ana Sofia d'Oliveira* / Federal University of Paraná - UFPR, Brazil
Feliciano Cangue / Federal University of Paraná - UFPR, Brazil
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| Abstract: |
Degradation of components that operate under elevated temperature and carburizing environments involves the diffusion of C and the precipitation of carbides. Industries have been seeking for materials that can withstand these service conditions such as the HP austenitic steels and Ni and Cr refractory alloys. The present work aimed to developed coatings to address this challenge through the enrichment of a Ni based alloy with Al. An atomized Ni alloy without Al and different powder mixtures with 15 and 30wt%Al were deposited by PTA on a carbon steel. Coatings were analyzed in the as deposited condition, at 650º and 850ºC in an air furnace and after pack cementation. Vickers microhardness profiles under a 500gf load, X-ray diffraction, optical and scanning electronic microscopy were done on the different testing conditions. Results revealed that the presence of Al lead to the development of a complex intermetallic phase which was associated with the enhanced metallurgical stability of the coatings under the tested temperatures. The superior performance of the coatings deposited with the powder mixture containing 15wt%Al after pack cementation should also be associated with good adherence of the double oxide layer (Al and Cr), that is expected to develop and is known to reduce the diffusion of C.
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