Katchin vs Adamantium vs Promethium

I know Katchin is a fictitious DBZ Metal and DBZ isn't allowed but, from what you have seen in the comics, on television and in manga which one is the strongest.

I'm gonna stick with Adamantium. 😎

=. except maybe the DBZ one, was it ever broke?

None of them.

Supermanium! Stronger than any other! 😄

Which one was Katchin again? I haven't seen DBZ in awhile, where was this metal shown/mentioned?

Katchin is the metal that was used when the The Supreme Kai was training Gohan to use the Z Sword, a legendary magical sword that was said to be able to cut anything, during the Buu Saga. He made a large block of it materialize out of thin air, then Gohan tested the blade to see how sharp it was by cutting the block.

The sword broke upon impact with the block, and didn't even scratch the surface of the Katchin.

Then Elder Kai comes out of the broken sword and does a chicken dance...