Mechanochemical Polishing of Silicon Nitride

Two oxides of iron, Fe 2 O 3 and Fe 3 O 4 , were identified as suitable soft abrasives for mechanochemical polishing of Si 3 N 4 . Removal rates up to 1.6 μ.m /h were observed when hot‐pressed Si 3 N 4 samples were mechanochemically polished using these abrasives on a linen plastic lap. The polished surfaces were flat and scratch‐free, with a peak‐to‐valley roughness of <20 nm. Auger electron spectroscopy of these surfaces revealed a thin layer (≤10 nm) of a silicon oxynitride that contained carbon and ∼0.5 at.% iron.