years ago i asked CarboneLorraine because they have recomended their sinter pads also for cast iron discs.
No problem...
I tried and switched back to something organic.
They did brake like hell, for my opinion
But they also produce a lot of black dust
Just to be shure i think.
So you have 2 choices.
Use something good organic.
Or switch to stainless discs.
ciao Joachim