Nickel 200 (UNS N02200)/Nickel 201 (UNS N02201)

Alloy 200/201 is extremely resistance to caustic alkalies up to and including the molten state. The extra-low carbon content of Alloy 200/201 gives virtual immunity to intergranular attack above about 315°C. The presence of chlorates must be kept to aminimum, as they accelerate the rate of attack.

Good resistance to corrosion in acids and alkalis and is most useful under reducing conditions. Outstanding resistance to caustic alkalis up to and including the molten state. In acid, alkaline and neutral salt solutions the material shows good resistance, but in oxidizing salt solutions severe attack will occur. Resistant to all dry gases at room temperature and in dry chlorine and hydrogen chloride may be used in temperatures up to 550C. Resistance to mineral acids varies according to temperature and concentration and whether the solution is aerated or not. Corrosion resistance is better in de-aerated acid.