Effect of Yttrium on High Temperature Oxidation Behavior of New-Type Fe-Ni-Cr-Al Alloy

The oxidation behavior of new-type Fe-Ni-Cr-Al alloys with different Y contents in air atmosphere at 1300 degrees C was studied by isothermal oxidation test. The type and distribution of oxidation products were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It is found that the addition of Y element is beneficial to the oxidation resistance of Fe-Ni-Cr-Al alloy. The reason is that the Y element can promote the formation of a dense composite protective layer of spinel and chromium oxide on the surface of Fe- Ni-Cr-Al alloy, and then slow down the diffusion of the elements in the matrix. At the same time, Y element can accelerate the transformation mode of Al2O3 from internal oxidation to external oxidation and slow down the internal nitridation process. And thus, the oxidation resistance increases.