Salt solutions high-nickel cast irons

Some austenitic cast iron types may show a level of sensitivity to stress corrosion cracking in seawater and salt solutions at higher temperatures [96]. At high nickel contents of around 35%, pitting corrosion increases [97]. 

Zirconium alloys generally have good corrosion resistance in salt solutions and are relatively insensitive to iron and nickel. When magnesium is alloyed with zirconium, most of the iron is present as insoluble particles in combination with zirconium (Chapter XX in Emley, 1966). As a consequence, the iron contaminant is precipitated from the alloys before casting. All zirconium-grain-refined alloys are high purity in iron, and to a lesser extent nickel, because these impurities are naturally controlled to very low levels by precipitation with zirconium (Tawil, 1990). 

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