Research on High Temperature Performance of CoCrAlSiY Coatings
Research on High Temperature Performance of CoCrAlSiY Coatings
Monday, May 27, 2019
Abstract: In this work, the high temperature oxidation resistance kinetics of CoCrAlSiY coating with different Si concentrations (0%, 2% and 5%) at 1000 °C and 1050 °C are investigated. The hot corrosion resistance of CoCrAlSiY coating at 800 °C and 900 °C are discussed by using hot salt coating method with a mixed salt of 75wt% Na2SO4+25wt% NaCl. Their thermal shock resistances at 1050 °C are also investigated. In addition, the oxidation and corrosion products of coating under the different experimental conditions are analyzed through the mineralogical and micro analysis. According to the above analysis, the mechanism of improving the coating performance by Si element are discussed. The results show that Si element promotes the formation of Al2O3 film at the high temperature, which is beneficial for improving the high temperature oxidation and corrosion resistances of coating. However, the excessive Si element causes an increase in the coating thermal expansion coefficient, which is unbeneficial for improving the coating thermal shock resistance.
Keywords: MCrAlY, Si, High temperature oxidation ; Hot corrosion; Thermal shock