piston ring galling

[abrasv]

I am using a suspended water-based abrasive (aluminum oxide) to lap steel piston rings in a recirculating vertical lapper. I am experiencing minimal galling issues at no particular time of the lap cycle. However, it is becoming apparent that after the 5+ cycle(load) is when it occurs mostly.
What might be added to this slurry that would control this galling?
The slurry itself is made up on DI water, a suspending agent and abrasive.

Oil based slurries are not an option because of enviromental issues.