Corrosion Resistant Alloy Development for Pb-Bi Eutectic Service

摘要

The Fe-Cr-Si system has been used as the basis for an alloy development program, the goal of which was the optimization of corrosion properties in Pb and Pb-Bi eutectic. The effect of Cr and Si additions to iron have been explored. The results of this investigation show that the addition of chromium and Si to iron results in the formation of a protective multi-layer system consisting of one or more of the following: (1) iron oxide, (2) chromium oxide, or (3) silicon oxide. At Cr concentrations greater than 12% and Si concentrations equal to or greater than 1.55 wt% an initially formed iron oxide layer is unstable and sloughs of leaving a double (chromium oxide/silicon oxide) layer. The alloys developed are being used as a protective cladding layer in the development of a functionally graded composite system consisting of a corrosion resistant barrier layer on top of a structural layer or either a Si-added T91 or ODS type material.