Samarium cobalt

What you use when it gets too hot for neodymium, or too wet.

Materials › Samarium cobalt
FormulaSmCo
Relative strengthStrong — below neodymium
Max operating temperature250–350 °C
Relative costHigh
Corrosion resistanceExcellent — usually needs no plating

You are paying for temperature, not strength

Weaker than neodymium of the same size, and considerably more expensive. The reason to choose it is that it holds its strength at temperatures where neodymium has already given up, and it barely corrodes.

It resists corrosion on its own

Unlike neodymium it does not generally need plating, which removes a failure point in wet or chemically aggressive environments.

It is the most brittle of the common types

Chips easily during handling and machining. Specify chamfers and expect a higher scrap rate on tight tolerances.

These figures are the ranges the trade works to and they move with grade, geometry and manufacturer. For anything load-bearing or safety-related, work from the datasheet for the exact part.

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