2003 Volume 52 Issue 8 Pages 408-415
A new stability index [an improved stability index (SI′)] has been proposed that introduces corrosion inhibiting ability of silica in a broad range of temperature and pH into the conventional index of the corrosive action and scale formation of water, and new empirical equations [Eqs. 1-3] that characterize water were derived using the new index. The derived SI′ was effective in the range of SI>6. The SI′ was balanced at 0, and then SI′=0 differed from SI=6. In addition, a possibility was found for prediction and inhibition of corrosion of ferrous metals based on the equations by controlling the concentration of silica ([SiO2]).
[y: corrosion rate (V) (mdd), K0: constant affecting saturation value of corrosion rate (y) (mdd), T: temperature (°C), [SiO2]: silica concentration (mg SiO2/dm3), x: stability index (SI) (-)]