English: STM image of surfaces at the edge of a 1 μm thick layer of ta-C "diamond-like" coating on 304 stainless steel after various durations of tumbling in a slurry of 240 mesh SiC abrasive. The first 100 min shows a burnishing away from the coating of an overburden of soft carbons than had been deposited after the last cycle of impacts converted bonds to sp3. On the uncoated part of the sample, about 5 μm of steel were removed during subsequent tumbling while the coating completely protected the part of the sample it covered.