Effects of pH and dissolved oxidizing agents on pitting corrosion of aluminum
スポンサーリンク
概要
- 論文の詳細を見る
The pitting corrosion of commercially pure aluminum was investigated in various solutions prepared by adding 5ppm of chloride ion, 5ppm of an inhibitor (a kind of ions of sulfate, silicate, and phosphate), and 0.55ppm of an oxidizing agent (a kind of hydrogen peroxide, chlorine water, calcium hypochlorite (bleaching powder), sodium chlorite, and nitric acid) to deionized water. The pH of the solutions was adjusted to 3.010.5 with dilute hydrochloric acid or sodium hydroxide solution. Corrosion tests were conducted in stagnant water at 35°C for 100hrs. The potentiostatic polarization measurements were also performed on some typical solutions.The results obtained were summarized as follows:(1) In the solution of pH range of 5.08.5 which contained no oxidizing agents other than the dissolved oxygen, the pitting corrosion of aluminum was very little when chloride and sulfate ions or chloride and silicate ions were contained. Whereas, a few macropits were observed in a solution containing chloride and phosphate ions.(2) The addition of 0.55 ppm of an oxidizing agent such as hydrogen peroxide or free chlorine to these solutions had powerful effects on the formation of pits. In particular, in a solution containing chloride and phosphate ions together with one of the above oxidizing agents, a large number of macropits were formed in a comparatively short time.(3) In general, the effects of these oxidizing agents on the formation of pits were less on the alkaline side rather than the acidic side.(4) The addition of 0.510ppm of nitric acid to the solution containing chloride and sulfate ions or chloride and phosphate ions accelerated pitting corrosion.(5) The effects of dissolved ions and oxidizing agents on pitting corrosion of aluminum mentioned above were discussed with respect to the polarization characteristics of aluminum in these solutions.
- 一般社団法人 軽金属学会の論文
一般社団法人 軽金属学会 | 論文
- Mechanical and wear properties of SiC whisker/ADC12 aluminum alloy composites fabricated by die casting.
- Joining of aluminum and ceramics.
- タイトル無し
- Undercooling and solidification behavior of fluid clumps of second-poured melt of hypereutectic Al-Si alloy in Duplex Casting process.
- Change in apparent viscosity of stirred slurry during production of semi-solid hypereutectic Al-Si alloy by slurry-melt mixing process.