Nature of the Oxide Film Present on Iron after Inhibition in 0·05 M Chromate Solutions

Abstract

Chemical and microprobe analyses have been used to study the composition of the oxide films formed on iron by 0·05 M potassium chromate, pH 4–8.

Chemical analyses have shown that the air-formed oxide film was thinned and evenly reinforced with a normal iron chromium spinel having a composition in the range Fe²⁺ (Fe³⁺ _0·5 Cr³⁺ _1·5)O₄ — Fe³⁺ Cr³⁺ O₃

Microprobe analyses indicated enrichment of chromium at scratch lines, but the effect was small compared with the overall thickening of the films.

Get full access to this article

View all access options for this article.

References

Hancock

, & Mayne

J E. O.

., J. chem. Soc., 1958, p. 4172

Hoar

T. P.

, & Evans

U. R.

, ibid., 1932, p. 2476

Wormwell

, Chemy Ind., 1953, p. 558

Cohen

, & Beck

A F.

., Z. Elektrochem., 1958, 62, 696

Bancroft

G. M.

, Mayne

J. E. O.

, & Ridgway

, Br. Corros. J., 1971, 6, 119

Mayne

J. E. O.

, & Ridgway

, ibid., 1971, 6, 244

Shell

H. R.

, Analyt. Chem., 1950, 22, 326

Smith

C. F.

, McCurdy

W. H.

, & Diehl

, Analyst, Lond., 1952, 77, 418

Sandell

E. B.

, ‘Colorimetric Determination of Traces of Metals’, 1959, p. 401 (London: Interscienc, e Publishers Inc.)

10.

Francis

J. M.

, & Whitlow

W. H.

, J. Iron Steel Inst., 1965, 203, 468

11.

Francis

J. M.

, J. appl. Chem., 1966, 16, 264

12.

Uda

, & Tsuji

, Corros. Sci., 1967, 7, 377

13.

Francombe

M. H.

, Physics Chem. Solids, 1957, 3, 37

14.

Brasher

D. M.

, & Kingsbury

A. H.

, Trans. Faraday Soc., 1958, 54, 1214

15.

Kubaschewski

, & Brasher

D M.

., ibid, 1959, 55, 1200

16.

Brasher

D. M.

, & Mercer

A. D.

, ibid., 1965, 61, 803

17.

Gilroy

, & Mayne

E. O., Corros. Sci., 1965, 5, 55

18.

Hancock

, & Mayne

J E. I.

., J. chem. Soc., 1958, p. 4167