Building Material for the Core of Toroidal Transformer
A list wort looking at....

Powder cores is advancment in Toroid technology. The units Hold Gaps, different material can be blended in this gaps to improve ferromagnetic properties of toroidal transformer.

Iron powder core are a old system and tend to fall for thermal aging effects. This type of Cores are coated with epoxy resin and Thermal stabilizers.

Soft Iron silicon steel toroidal core made of strips that are rolled in round shape. This give the toroidal shape. They can not be used directly on the transformers and need to be annealed before being used. It improves the magnetic properties of the soft iron. Ths is how our cores are built.

laminated iron Transformer Core are alloy made of iron and nicke. This is wound in to round toroidal shape same as the soft iron silicon steel core, spot welded to seal the setup.

Ferrite core Iron oxide mixed with compounds of manganese or zinc and in some cases nickel is compressed in a pre formed die using hydraulix press at a very high preasure. This high preasure converts the powder in to a solid brick with the shape of the die it was compressed into. This powder brick is still britle and unstable. To get the true and powerfull properties out of the ferrite core they are baked at a very high temperate, usually above 1200 degree centigrate. Usually most metel melt at this point and the core on the other hand kind of cures to become the material that was planned. Some times the output product has finishing issues and are polished or ground to final finish.