Abstract
<title>Abstract</title> <p>Aiming at the industrial pain points that thin-walled hard-brittle quartz crucibles are prone to surface defects including chipping pits and microcracks during machining, which results in a high scrap rate and failure to satisfy the application requirements for monocrystalline silicon drawing, Chemical Mechanical Grinding technology was employed to realize ultra-smooth repair of the surface defects. A kinematic model describing the critical conditions for plastic removal in grinding of brittle materials was established. The influences of abrasive grain size, grinding wheel rotational speed, feed rate and intermittent feeding mode on grinding force, surface morphology and roughness of quartz in Chemical Mechanical Grinding were systematically explored, and the key process parameters were optimized. The feasibility of the proposed process was validated via defect repair experiments conducted on 32-inch quartz crucibles. With the optimized parameters including 20 µm abrasive grain size, 8000 r/min grinding wheel speed and 0.2 mm/s intermittent feed rate with one second feeding followed by two minutes dwelling, the surface roughness Sa of the defective region on the quartz crucible was reduced to 29.204 nm. X-ray photoelectron spectroscopy characterization demonstrated that quartz reacts with alkaline grinding fluid to generate soft silicate compounds during Chemical Mechanical Grinding, and efficient plastic removal is realized under the synergistic effect of mechanical force. The findings of this study provide a theoretical foundation and technical support for surface defect repair and ultra-smooth machining of thin-walled hard-brittle quartz crucibles.</p>