The corrosion resistance of Niobium metal against metal melts
Niobium is resistant to many metals and chemicals. Niobium’s high level of resistance can be achieved at a low weight and it can be formed in a relatively low temperature. So it can be turned into colorful coin inserts, corrosion-resistant evaporation boats and other diamond growth crucibles.
Niobium is resistant to a series of metal melts such as Pb, Cd, Cs, Cu, Ga, Li, Mg. However, the material is not resistant to Al, Be, Ni, Zn and Co.
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Corrosion resistance against metal melts |
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Aluminum |
not resistant |
Lithium |
***resistant at < 1 000 °C |
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Beryllium |
not resistant |
Magnesium |
***resistant at < 950 °C |
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Lead |
***resistant at < 850 °C |
Sodium |
***resistant at < 1 000 °C |
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Cadmium |
***resistant at < 400 °C |
Nickel |
not resistant |
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Caesium |
***resistant at < 670 °C |
Mercury |
***resistant at < 600°C |
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Iron |
not resistant |
Silver |
***resistant at < 1 100 °C |
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Gallium |
***resistant at < 400 °C |
Bismuth |
***resistant at < 550°C |
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Potassium |
***resistant at < 1 000 °C |
Zinc |
not resistant |
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Copper |
***resistant at < 1 200 °C |
Tin |
not resistant |
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Cobalt |
not resistant |
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Noble gases can be used as protective gases as Niobium does not react with it. However, under high temperature, niobium reacts strongly with airborne oxygen, nitrogen and hydrogen. Oxygen and nitrogen can be removed again by annealing the material in a high vacuum at temperatures above 1 700 °C. Hydrogen is removed at lower temperatures of approximately 800 °C. The process results in a loss of material due to volatile oxides and the recrystallization of the structure.
