Corrosion prevention microstructure

The most common microstructural effect on the corrosion resistance of nickel alloys is intergranular sensitization, as previously mentioned. This is the result of chromium carbide precipitation in many Ni-Fe-Cr alloys but can result from intermetallic Mu-phase precipitation in low-carbon highly alloyed materials such as alloy C-276 (UNS N10276). Several standard IGA tests (discussed in the Intergranular Corrosion section) are available for determining (1) if stabilized alloys have been properly annealed to prevent subsequent sensitization, and (2) if nonstabilized alloys are free from significant sensitization as produced. 

Corrosion inhibitors are chemical compounds that, when added in adequate (preferably small) amounts to the concrete mixing water, can prevent corrosion of the rebars. These admixtures should not adversely affect the concrete properties (e.g. compressive strength) and the nature and microstructure of the cement paste. Inhibitors -well known in other areas of industry - have been studied since 1960 for reinforcing steel in concrete, mainly in relation to chloride-induced corrosion. A summary of information on steel corrosion inhibitors in concrete have been published (Page and Ngala, 1999 Elsener, 1998) and a state of the art report is to be published shortly by the European Federation of Corrosion (EFC, 1999). 

Stein AA (1993) MIC treatment and prevention. In A practical manual on microbiologi-cally-influenced corrosion Kobrin G (ed) NACE Houston Texas USA Lee J (1998) Bacterial biofilms less likely on electropolished steel Agricultural Res p. 10 Percival SL, Knapp JS, Wales DS, Edyvean RGJ (2000) Metal and iuorgauic ion accumulation in biofihns exposed to flowing and stagnant water. Brit Corrosion J 36(2) 105-110 Sreekumari KR, Nandakumar K, Kikuchi Y (2004) Effect of metal microstructure on bacterial attachment A contributing factor for preferential mic attack of welds. Paper No. 04597. CORROSION 2004, NACE International... 

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