# Synergistic Multi-Mechanism Enhancement in Chemomechanical Abrasive Polishing of Polycrystalline Diamond via a New SiO2–Diamond Slurry in High-Concentration H2O2 Solution

## TL;DR

A new polishing method using a special slurry improves the efficiency and quality of polishing polycrystalline diamond wafers.

## Contribution

A novel SiO2–diamond slurry in high-concentration H2O2 solution enhances chemomechanical polishing of PCD.

## Key findings

- The optimal slurry composition (60% SiO2 and 40% diamond) achieved a 15.5% higher material removal rate than mechanical polishing.
- Surface roughness was reduced to 1.39 µm due to the formation of a lubricating layer from SiO2.
- Mechanical action was the primary contributor to material removal, with chemical and cavitation effects playing secondary roles.

## Abstract

The high-efficiency polishing of large-sized polycrystalline diamond (PCD) wafers continues to pose significant challenges in its practical applications. Conventional mechanical polishing suffers from a low material removal rate (MRR) and surface damage. To improve the process efficiency, this study investigates the effect of chemomechanical abrasive polishing (CMAP) with a slurry containing high-concentration H2O2 and varying mass percentages of SiO2 powder and diamond particles on surface morphology, surface roughness, material removal rate (MRR), and microstrain of PCD disks. The contributions of mechanical action, chemical action, and bubble cavitation to the CMAP process are analyzed. Scanning electron microscopy (SEM) observations indicate that large grains present in PCD are effectively eliminated after CMAP, leading to a notable reduction in surface roughness. The optimal results are obtained with 60 wt% SiO2 powder and 40 wt% diamond particles, achieving a maximum MRR of 1039.78 μm/(MPa·h) (15.5% improvement compared to the mechanical method) and a minimum surface roughness (Sa) of 3.59 μm. Additionally, the microstrain on the PCD disk shows a slight reduction following the CMAP process. The material removal mechanism is primarily attributed to mechanical action (70.8%), with bubble cavitation and chemical action (27.5%) and action of SiO2 (1.7%) playing secondary roles. The incorporation of SiO2 leads to the formation of a lubricating layer, significantly reducing surface damage and decreasing the surface roughness Sa to 1.39 µm.