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| Abstract No.: |
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Scheduled at:
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Tuesday, June 03, 2008, Room 05 1:40 PM
Case Studies and Further Applications 2
showing the broad variety of thermal spraying in different examples, special processes and also specialised materials apart from standard coatings offer new possibilities and also new markets
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| Title: |
Molten zinc corrosion of WC-Co coatings in Al-added zinc bath
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| Authors: |
Tsai-Shang Huang* / China Steel Corporation, Taiwan, Taiwan
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| Abstract: |
To increase the service life of a sink roll in a continuous galvanizing line has been an important issue in steel industry. It was shown that sink rolls are vulnerable to molten zinc corrosion and can be improved by thermal spraying with WC-Co coatings. Three WC-12Co powders with different WC particle size were used to make coating samples by HVOF using a DJ2700 gun. Samples were then immersed in Al-added zinc bath (480C) for testing. The results show that coatings with micro WC particle size are more resistant to molten zinc corrosion than those with nano WC particle size. It is possible due to more Co sites contacting with zinc bath in the nano WC coatings and corrosion occurred through inter-diffusion between Co and Zn. Al was found to be enriched on the coating surface. Although the effect of Al-rich phase is still not clear, it is likely to act as a barrier to retard the inter-diffusion between Co and Zn.
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