湿潤雰囲気でのSi含有フェライトステンレス鋼の高温酸化挙動

抄録

Effect of Cr and Si contents in the ferritic stainless steels on the occurrence of reddish brown oxide scale in the kerosene-combustion atmospheres has been studied in the O₂+H₂O+Ar mixed gases and the combustion portions of kerosene heaters. Furthermore, their effects have been studied in detail by the observation and analysis of the produced oxide scales. In the results, the oxidation behaviour of Cr steels in the O₂+H₂O+Ar mixtures showed good coincidence with those in the kerosene heaters. Namely, Cr and Si show good effect to prevent the formation of the reddish brown oxide scale. It was found that this good effect can be attained by increasing Cr and Si in the steel following a condition Cr(%)+4Si(%)≥27. When a reddish brown oxide scale occurs, (Cr, Fe)₃O₄ as well as (Cr, Fe)₂O₃ was produced in the initially formed oxide scale. In order to prevent the formation of the reddish-brown oxide scale, it was found that the initially formed oxide scale must be M₂O₃ type which can be attained by the highly Cr-enriched scale (Cr/Fe ratio≥3). Furthermore, Si may enrich Cr in the scale and prevent the oxidation of Fe.