Relating to the absorption refrigeration and heat pump systems, corrosion of carbon steel and its inhibition by hydroxide and molybdate were studied in various LiCl solutions of 1-15m (mol/kg-H2O) at 100-160°C.
The increase in LiCl concentration suppressed corrosion of carbon steel slightly at 100-140°C, whereas it promoted corrosion slightly at 160°C. Corrosion morphology was general corrosion, and magnetite particles adhered on the surface. The complicated features of corrosion are described by the several natures of the solution and adhered corrosion products.
Both hydroxide and molybdate were effective to reduce corrosion, but pitting was likely to occur in the LiCl solutions of low and intermediate concentrations. In the highly concentrated solutions, on the other hand, only simultaneous use of hydroxide and molybdate was effective for passivation; Otherwise heavy general corrosion was observed. The results are discussed in terms of competitive actions between chloride and hydroxide ions and other natures of the solution.
