NdFeB can be heat resistant up to 150 degrees Celsius or higher, it depends on your application, just enough is good or it is a waste, like this product you are browsing now is a heat resistant 180 degrees Celsius ring magnet, N38SH grade, zinc plated surface, blue-white color, outer diameter 25mm, hole in the middle 19mm, thickness 2mm, the magnetization direction is not axial but radial, if you are interested in this size If you are interested in this size or have any other ideas you can contact us through the online inquiry tool below or on the website.
Note: If you can't figure out whether your toroids are axial or radial check out this article "Axially magnetized vs diametrically magnetized"
Articles that may be helpful to you;
Diametrically Radially Magnetized Ring Magnets
Radial Ring Magnets [Meaning Uses Magnetization Diagram]
What is a radial magnets? What should I consider when buying?