Results and discussion

Effect of Cr content on mass loss by immersion and coated tests are shown in Fig. 1. Mass loss after corrosion tests was reduced with high Cr content for all conditions tested. The developed alloy showed the highest corrosion resistance in both test methods.

Chemical analyses of salt after corrosion test are shown in Table 2 and Table 3. After immersion test, Cr was identified from salt and only a little amount of Fe and Ni were detected. No residuals were found in salt used for immersion test after extraction by water.

In soluble substance, a small amount of Fe and Ni was found but only Cr was identified as alloy element On the other hand, in residuals, Fe and Ni were determined but Cr was not found for type 304, 316L and 30%Cr-45%Ni alloy. Only for type 31 OS Stainless steel, a little amount of Cr was identified. This result suggested

Table 2 Metal ion concentration in salt after 205 and 500 hours immersion test at 650°C(%, Original weight of salt was 40g respectively)
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