SCREENING TEST OF MATERIALS FOR IODINE-SULFUR PROCESS IN SULFURIC ACID SOLUTION

摘要

The corrosion behavior of some commercial materials such as Fe-Cr, stainless steel,Ni base alloy and SiC were evaluated in boiling sulfuric acid to select a materials used in Iodine-Sulfur (I-S) Process which is one of methods for hydrogen production using high temperature heat. The high temperature heat will be generated by High Temperature Gas-cooled Reactor (HTGR). Immersion tests were performed in 97percent H_(2)SO_(4) solution. The tests were performed in a pyrex glass flask with a capacity of 1L. Corrosion rates were measured with weight changes after immersion test, and the surface observation was performed for each specimen. The corrosion rates of Fe-Cr alloys were considerably faster than the other alloys. The Ni-base alloys have better corrosion resistance than other alloys except alloy 600. Sanicro 28 and alloy 800 had better resistance than other stainless steels. SiC had best corrosion resistance. In the test of Fe-Cr alloys, the corrosion rate was increased with decreasing Cr contents. From the test results, the corrosion rates of Fe-Cr alloys were related to the Cr. In other alloys (Ni-base alloys, stainless steels) test, the corrosion rates were not largely affected by Cr contents. Intergranular corrosion were found in alloy 600 and alloy 800 surfaces. From the microstructure observation, carbides were distributed in the grain boundary region and these carbides affected the grain boundary corrosion. The partial corrosion marks were found in the surfaces of some stainless steels. In the case of Fe-Cr alloys, the general corrosion marks were observed.