EFFECT OF RARE EARTH ADDITIVES ON THE QUALITY OF Fe-Cr-Al ELECTRIC HETING ALLOY
Luo Chi-hsun;Yin Yao-teh;Lin Sheng-kun;Chao Chi;Wang Chien
Cite this article:
Luo Chi-hsun;Yin Yao-teh;Lin Sheng-kun;Chao Chi;Wang Chien. EFFECT OF RARE EARTH ADDITIVES ON THE QUALITY OF Fe-Cr-Al ELECTRIC HETING ALLOY. Acta Metall Sin, 1977, 13(4): 263-359.
Abstract To ascertain the effect of rare earth additives on the quality of Fe-Cr-Alelectric heating alloy, the rapid heating life test and oxidation kinetics studyof three specimens: (A)-plain alloy, (B)-added 0.038％ La-Ce mixture, and (C)-added 0.49％ Y, have been examined. The observations of morphology andadhesivity of the oxidized layer reveal that in the interior of specimen C afterexposed for 350 hours under 1200℃, a new phase which has been identified asyttrium-aluminium-garnet (Y_3Al_5O_(12)) was present. This might have a direct in-fluence upon the adhesivity of the surface oxidized layer. In the case of the plain alloy, exposure at high temperatures gave rise tograin growth with rapid deterioration in the mechanical properties of the speci-men. The addition of rare earth, especially of yttrium, was found to be effec-tive in preventing crystal growth and therefore exerted correspondingly goodinfluence upon the mechanical properties of the specimen at high temperatures.Such may be the reason why the rapid heating life of alloys with the additionof rare earth is longer than without.
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