Effects of Lanthanum on Fe-25Cr Alloys under Cyclic Oxidation
Fe-Cr binary model alloys (Cr: 25 wt %) with additions of 0.09 wt% lanthanum were subjected to cyclic oxidation experiments at 700oC. All model alloys were exposed in five different gases; Ar-20O2, Ar-20O2-5H2O, Ar-5O2-20H2O, Ar-10H2-5H2O (pO2 = 3.64 x 10-22 atm) and Ar-10H2-20H2O (pO2 = 7.37 x 10-21 atm) all in volume %. Very low weight gains were observed in all gases of Fe-25Cr-0.09La. However, breakaway oxidation occurred on La-free alloy experienced increased weight gain in Ar-5O2-20H2O due to formation of iron-rich oxide. The addition of La (<0.1 wt%) to the Fe25Cr retarded the growth of iron-rich oxide in Ar-5O2-20H2O.
Zhengyi Jiang and Chunliang Zhang
N. K. Othman et al., "Effects of Lanthanum on Fe-25Cr Alloys under Cyclic Oxidation", Advanced Materials Research, Vols. 97-101, pp. 1212-1215, 2010