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1334 |
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Tuesday, June 03, 2008, Room 04 9:10 AM Corrosion Protection 1 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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Corrosion performance of arc sprayed Zn, Zn/Al 85/15 coatings on ductile iron pipe |
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Ahmet Turk / Sakarya Universtiy, Department of Metallurgical and Materials Engineering , Turkey Ahmet Gulec* / Sakarya University Department of Metallurgical and Material Engineering, TURKEY Ozgur Cevher/ Sakarya University Department of Metallurgical and Material Engineering, TURKEY Fatih Ustel/ Sakarya University Department of Metallurgical and Material Engineering, TURKEY Fevzi Yilmaz/ Sakarya University Department of Metallurgical and Material Engineering, TURKEY |
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Ductile iron pipes have been used worldwide since 1960s for water transmission and distribution mains. By 1979, ductile iron pipe largely replaced cast iron as the predominant material in water industry. For protection of the ductile iron pipe against corrosion in heterogenic soil conditions, Zn and Zn/Al 85/15 coatings are applied by twin wire arc spray technique. In this study, heat treated and non-heat treated ductile iron pipe samples were coated with Zn and Zn/Al 85/15 in optimum spray parameters by wire arc spraying technique. The coatings were investigated by optical microscopy, scanning electron microscopy (SEM), and analyzed by energy dispersive x-ray technique (EDS). The protection performance of the coatings was compared with accelerated corrosion (salt spray) test according to the ASTM B 117 and corrosion products were analyzed by XRD technique. Salt spray test results showed that Zn/Al 85/15 coatings have better corrosion resistance than Zn coatings and annealing oxide on ductile iron pipe acts as a very corrosion resistant protective layer. Keywords: Twin wire arc spraying, ductile iron pipe, Zn coating, Zn/Al 85/15 coating, corrosion, salt spray |