Environmental Surface Degradation of Galvanised andudMild Steels in Cattle and Poultry Wastes and UreaudSolution

摘要

An investigation of the corrosive properties of cattle and poultry dung/urine slurries and urea solution and by extension, the corrosion resistance of galvanised and mild steels in these respective test media was performed by the weight loss method. The results showed corrosive surface degradation of galvanised steel and extensive corrosion of the mild steel test specimens by the corrosive constituents of the various test media. The corrosive constituents in the slurries are believed to be urea, uric acid,ammonia and ammonium salts, naturally excreted chloride (common salt), carbon-dioxide and sulphate reducing and sulphur oxidizing bacteria. The galvanised steel is found to be more corrosion resistant than the mild steel. The cattle dung/urine slurry was found to be the most aggressive of the test media and the poultry dung/urine slurry, the least corrosive medium.