Effect of Yttrium on Cyclic Oxidation Behavior of FeCrNi Heat Resistant Steel

The cyclic oxidation tests of heat resistant steel Fe-21Cr-11Ni were carried out at 1 100 ℃,1 150 ℃ and 1 200 ℃ by using weight gain method.The influence of yttrium on the oxidation resistance of the heat resistant steel was examined by XRD,SEM and EDX.The results showed that the oxidation resistance of the heat resistant steel was improved remarkably after adding yttrium.During oxidation process the diffusion of chromium to the scale could be promoted by yttrium.On the surface of the heat resistant steel containing yttrium,the dense and adherent Cr2O3 scale and FeCr2O4 scale were formed and played the protection role.In the internal oxidation layer,the pinning effect of silicon dioxide was strengthened by yttrium,and yttrium had a pining effect directly.