Corrosion Resistant Behavior of Silver-Zinc Alloys in Air-1% H2S
1986 Volume 35 Issue 6 Pages 334-339
Details
1986 Volume 35 Issue 6 Pages 334-339
Ag-Zn alloys containing Zn over a range of 7 to 89% were exposed to Air-1% H2S with 2 or 90% relative humidity. After exposure periods of up to 20 days, the thickness of corrosion product layer was estimated by coulometric reduction. The composition and structure of corrosion product were investigated by XMA, AES and X-ray diffraction methods.
The results obtained are summarized as follows.
1) The desirable compositions to anti-tarnishing were in the range of 36 to 51% Zn, which gave the minimum surface film thickness.
2) Surface film thickness on the most corrosion resistant alloy was estimated approximately 1/100 by coulometric reduction, as compared with the film thickness on pure Ag.
3) AES data indicated that the corrosion products on the alloys containing more than 36.9% Zn mainly consisted of Zn compound with S. Conversely, XRD and AES data showed Ag2S with or without Zn, on the alloys containing less than 24.7% Zn.
4) The results obtained by AES were in reasonable agreement with the results obtained by coulometric reduction.
