High-temperature corrosion and mechanical properties of protective scales on Incoloy 800H: The influence of preoxidation and ion implantation

Coatings, obtained by preoxidation of Incoloy 800H at low PO2 show good sulphidation resistance due to the higher chromia content in the oxide scale. Yttrium-ion implantation of Incoloy 800H has also a beneficial effect on sulphidation, if preoxidation is applied. The reason for this is presumably the segregation of yttrium to grain boundaries of the oxide. Furthermore, the oxidation kinetics of Incoloy 800H are independent of the partial pressure of the oxygen. Mechanical testing of the preformed oxide scale/substrate combinations in air at 600°C by means of constant-extension-rate experiments shows that preoxidation at low partial pressures of oxygen leads to earlier scalecracking.