Aluminium—thiourea inhibitors of mild steel corrosion in high specific salinity water. Compatibility with calcium, magnesium and ferrous ions at various temperatures
✍ Scribed by M. Iovchev
- Publisher
- Elsevier Science
- Year
- 1985
- Tongue
- English
- Weight
- 605 KB
- Volume
- 52
- Category
- Article
- ISSN
- 0011-9164
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✦ Synopsis
Aluminium-thiourea (Al-thi) inhibitors were found to provide good inhibition of mild steel in water of a high specific salinity (1.0% Na,SO,) considered characteristic for recirculating water of zero-discharge cooling systems in steam plants. As in a real cooling system this water would contain calcium, magnesium and ferrous ions, a successful application of Al-thi inhibitors would depend on their compatibility with these ions. In order to check this compatibility the inhibitive efficiencies of two representative Al-thi inhibitor formulations were measured in the presence of Ca*+ (as CaS04), Mg*+ (as MgS04) and Fe*' (as FeS04 and FeC12) using the weight loss method according to NACE Standard TM 01-69 at 20-40°C. It was found that the inhibitive efficiencies of the tested formulations sharply decreased in the presence of Ca*+ while the action of Mg*+ and Fe*+ does not appear to have a critical influence on the inhibitive properties of the same formulations. This finding showed that the application of Al-thi inhibitors in zero-discharge cooling systems can be successful if a complete removal of Ca*' from both makeup and recirculating water would be foreseen. Due to the high cost of this removal, in some cases the application of mild steel in conjunction with Al-thi inhibitors cannot be justified in zero-discharge cooling systems. SYMBOLS a -weight loss, g I-efficiency of inhibitors tested, %