Evaluation of Alternative Corrosion Inhibitors for Gas-Fired Ammonia/WaterRefrigeration Machines. Final Report, April 1993-April 1995

摘要

The report presents the test results on the use of silicate compounds chosen asenvironmentally safe alternatives to the sodium chromate corrosion inhibitors that are currently used to protect carbon steel surfaces in ammonia/water refrigeration machines. Silicates were selected from a larger group of compounds for testing in standard, residential 3-ton ammonia water chillers after they had been screened for their effectiveness by electrochemical techniques, coupon immersion tests in autoclaves, and tests in chillers. Various surface pretreatments using silicates were also tested in an attempt to avoid stress-corrosion cracking (SCC) that had occurred in previous studies using silicate-inhibited chillers that had been pretreated with sodium nitrate.