My girlfriend chipped my ceramic Kyocera Kyotop 155mm gyuto awhile back, and I just repaired her on diamond. I started cautiously on the Atoma 1200, and it didn't cut the ceramic. I went down to an Atoma 600, and saw some removal but not much. I pulled out the Atoma 140 with total faith I would get past those chips in no time. damn is this stuff hard! I got past the chips, but the 140 is so coarse & the ceramic so brittle... it ate the edge & caused 5 times more damage than had been originally inflicted. I was so pissed.
I went back up to the 600, and it's one of Ken's quarter plates so it's like 2"x3"... IT TOOK FOREVER TO GRIND PAST ALL THE CHIPPING W/THAT LITTLE DAMN THING. Anyhow, the progression went Atoma 600, Atoma 1200, then Ken's 6 micron diamond film on glass. It needs 3 micron & 1 micron lapping to get close to my steel edges, but damn does it feel nice in the meantime.
This was my first time sharpening a ceramic blade, and I'm really surprised how the ceramic cutting edge polishes out to look very similar to steel. It didn't come that way; new it was totally black. BEFORE:AFTER: