Material removal mechanism of single-crystal SiC polished by pore-confined free abrasive polishing disc based on the ethanol-dissolvable shell of Diamond@PFR composite abrasives

To address the low material removal rate (MRR) and low abrasive utilization of free abrasives as well as severe surface damage in fixed abrasive polishing, this paper proposes a pore-confined free abrasive (PC-FA) polishing disc based on Diamond@phenol-formaldehyde resin (PFR) composite abrasives for single-crystal SiC. In ethanol slurry, the PFR shell of composite abrasives dissolves selectively, confining the inner diamond cores within in-situ generated pores to act as dynamic free abrasives for high-quality, low-damage precision machining. Diamond@PFR abrasives were synthesized by solution suspension and characterized via SEM, XRD and LPSA. Three polishing discs (fixed diamond, fixed composite, PC-FA) were fabricated for comparative polishing tests. The PC-FA polishing disc achieved an MRR of 1.07 μm·h −1 and an Sa of 1.38 nm, reduced the surface roughness by 54.6% and 48.1% compared with the two fixed abrasive polishing discs. ABAQUS simulations combined with friction tests clarify the removal mechanism. Fixed abrasives bear rigid constraints, causing concentrated contact stress, deep straight scratches and two-body wear. Pore-confined diamonds move randomly with multiple degrees of freedom, thereby homogenizing stress and generating shallow and sparse scratches, as reflected by a reduced Rku value and an elevated Rsm value, with flexible three-body wear dominating material removal. This disc realizes in-situ fixed-to-free abrasive transition, achieving moderate material removal with high-quality and low-damage machining, and offers a new route for processing third-generation semiconductor substrates.