Abstract
The corrosion resistance of boronized and unboronized steels against various chemicals has been investigated. The samples of SPCC, S15C, S35C and SPH were boronized at 950°C for 3hr or 6hr in the salt consisting of H3BO3: 40wt%, K2B4O7·5H2O: 20wt%, NaF: 15wt%, K2CO3: 15wt%, and Mg powder: 10wt%. As the corrosive media, water, NaCl, H2SO4, HCl, HNO3, H3PO4, HF, C3H6O8, NH4NO3 and HCO2H were used. The tests were performed at room temperature as well as at high temperatures (60 or 90°C). The results obtained were summarized as follows: The boronizing of steel remarkably increases the corrosion resistance against 0.5N-H2SO4, HCl, 60°C 85%-H3PO4, 47%-HF, 90°C 8%-C3H6O8, 60°C 50%-NH4NO3 and 60°C HCO2H. However, it does not improve the corrosion resistance against water, 10%-NaCl, 36N-H2SO4, 60°C 36N-H2SO4 and HNO3.
