クロムイオンを含む沸騰濃硝酸中でのステンレス鋼の腐食

スポンサーリンク

概要

• 論文の詳細を見る

• As a result of investigations of the mechanism through which the corrosion of stainless steels in boiling concentrated HNO_3 could be accelerated the following facts were made clear. (1) The oxidizing power in terms of steady potential of a platinized platinum electrode attains its maximum at the azeotropic concentration. In case of addition of Cr^<6+>, the power increases with the logarithmic amount added, indicating a positive slope of about 16 mV which corresponds to the oxidation number 3, while in case of addition of Cr^<3+> a negative slope of about 33 mV which corresponds to the number 1.5 is observed, the latter reason may be ascribed to partial oxidation of Cr^<3+> to Cr^<6+>. Furthermore, increment or decrement of the power is dependent on the Langmuir adsorption type curve. (2) The corrosion of none-sensitized austenitic stainless steels can be accelerated either by addition of tri-or hexa-valent ions, the influence of which becomes maximum in the azeotropic acid, where the logarithmic corrosion rate is in direct proportion to the power. The cause by which the addition of Cr^<3+> can accelerate corrosion may be sought in the easer oxidation on the steel surfaces. (3) When Cr^<6+> is added, the higher the chromium content in the steels the higher becomes the corrosion rate, but when Cr^<6+> is not added the inverse result can be observed, i.e. the former corrosion may be in the transpassive region while the latter corrosion in the passive region. Nickel and molybdenum alloyed in the traditional amounts may, if anything, be taken as increasing the susceptibility to accelerating effect of Cr^<6+>. (4) In the addition of Cr^<6+> corrosion of 18-9 and 18-11-Mo type steels increases as the carbon content is decreased, whilst in no addition the state of affairs is inversed. As a rule, all above results may be influenced some important factors as rate of escaping NO_2 as well as the test duration, and so on.

• 社団法人日本材料学会の論文
• 1968-08-15

著者

• 木島 茂

  住友化学工業(株)新居浜製造所

関連論文

• 腐食・防食の科学と工学(VI) : 防食工学 その3(防食管理)
• クロムイオンを含む沸騰濃硝酸中でのステンレス鋼の腐食
• 腐食研究体制の結集を
• 装置工業と腐食の管理 : 防食管理
• 水の性質と腐食
• オーステナイト系ステンレス鋼の腐食疲労に関する研究(第5報) : 表面圧延と焼ばめの影響
• オーステナイト系ステンレス鋼の腐食疲労に関する研究(第4報) : カソード電流の印加および酸化性カチオン添加の影響
• オーステナイト系ステンレス鋼の腐食疲労に関する研究(第3報) : 予備繰返応力と予備腐食の影響
• オーステナイト系ステンレス鋼の腐食疲労に関する研究(第2報) : 液温および繰返速度の影響
• オーステナイト系ステンレス鋼の腐食疲労に関する研究(第1報) : 希酸溶液中における316型ステンレス鋼の腐食疲労挙動

スポンサーリンク