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6426 |
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High temperature corrosion behavior of selected thermally sprayed alloy based coatings in aggressive environment at 800°C |
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Zdenek Cesanek* / Vyzkumny a zkusební ustav Plzen s.r.o., Czech Republic Frantisek Lukac / Institute of Plasma Physics, The Czech Academy of Sciences, Czech republic Sarka Houdkova/ Vyzkumny a zkusebni ustav Plzen s.r.o., Czech republic Katerina Lencova/ Vyzkumny a zkusebni ustav Plzen s.r.o., Czech republic Radek Musalek/ Institute of Plasma Physics, The Czech Academy of Sciences, Czech republic |
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This study is focused on the hot corrosion evaluation of selected thermal sprayed coatings. NiCoCrAlYHfSi, NiCoCrAlY, NiCoCrAlTaReY and CoCrAlYTaCSi coatings were sprayed on the substrate material 1.4923. This material is used as a cost-efficient construction material for components of power equipment. All evaluated coatings were sprayed using HP/HVOF (High Pressure / High Velocity Oxygen Fuel) technology. Hot corrosion studies were performed in a molten salt environment typical for coal-fired boilers. All coatings were exposed to the environment of 75 % Na2SO4 and 25 % NaCl at the temperature of 800 °C under cyclic conditions. Each cycle consisted of 1h heating in silicon carbide tube furnace followed by 20 min of cooling. The weight change measurement was performed after each cycle to establish the corrosion kinetics. Scanning electron microscopy (SEM), elemental analysis (EDS) and optical microscopy (OM) were used to analyze the corrosion mechanism. CoCrAlYTaCSi coating showed the best corrosion resistance of all evaluated coatings. |