著者

諸石 大司 志田 善明

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.42, no.3, pp.316-323, 1978 (Released:2008-04-04)

参考文献数

21

被引用文献数

1 1

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The oxidation of pure titanium was studied in superheated steam at 400∼550°C. The effects of prior cold working and several heat treatment conditions on the oxidation were examined and also the effects of the addition of small amounts of iron and oxygen were investigated. The oxidation mechanism of pure titanium is discussed in relation to the scale structure and the oxidation kinetics. Hydrogen absorption rate was also measured. As a result, the following conclusions were drawn:(1) The oxidation of pure titanium in steam was faster than in air and breakaway oxidation was observed above 500°C after the specimen had gained a certain weight. Prior cold working and heat treatment conditions scarcely affected the oxidation rate, whereas the specimen containing small amounts of iron and oxygen showed a little more rapid oxidation.(2) At 500 and 550°C a dark grey inner scale and a yellow-brown outer scale were formed. The outer scae was apt to exfoliate after the occurrence of breakaway oxidation. At 400 and 450°C only a dark grey scale was observed. All of these oxides were identified as the rutile type, TiO2. Furthermore, the presence of a thin and uniform oxygen rich layer beneath the external scale was confirmed at all test temperatures.(3) The measured weight gain approximately followed the cubic rate law; this would be expected for the following reason; one component of the weight gain is due to the dissolved oxygen, the amount of which remains constant after the early stages of oxidation. The second component is due to the parabolic growth of the external TiO2 scale. When these contributions are added a pseudo-cubic weight gain curve results.(4) It was shown that 50 percent of the hydrogen generated during the oxidation was absorbed into the metal.

著者

村山 順一郎 北山 司郎 幸 英昭 志田 善明 市橋 弘行

出版者

社団法人日本鉄鋼協会

雑誌

鐵と鋼 : 日本鐡鋼協會々誌 (ISSN:00211575)

巻号頁・発行日

vol.72, no.5, 1986-03-04