Effect of graphite additive on physical, mechanical, and wearing properties of Al₂O₃/E-glass/phenol formaldehyde hybrid composite grinding wheel

Abstract

The research was conducted to develop and assess the performance of composite grinding wheels enhanced with a graphite additive. These composite wheels were composed of aluminum oxide as abrasive and reinforcement material, E-glass as a reinforcement material, and phenolic resin as the matrix material. Various concentrations of graphite (4%, 8%, 12%, and 16% by weight) were incorporated into the composite formulations. Aluminum oxide, phenolic resin, and graphite were hand-stirred and combined. The mixture was then compressed at 94.4 MPa at room temperature, followed by heat treatment at 204°C for 50 min. The incorporation of graphite into Al2O3/E-glass/phenol formaldehyde composite grinding wheels significantly enhanced their mechanical properties and grinding performance. Increasing the graphite content up to 12 wt% in grinding wheels (GW3) resulted in a steady increase in density (from 1.9 g/cm³ to 2.1 g/cm³) and a corresponding decrease in porosity (from 16.5% to 3.6%) compared to the 4 wt% graphite-filled grinding wheels (GW1). Moreover, GW3 showed improvements in push-out strength by 60.6% (from 4.1 MPa to 6.57 MPa) and compressive strength by 15.7% (from 21.8 MPa to 25.17 MPa) compared to GW1. Wheels containing 16 wt% graphite (GW4) exhibited the lowest wear rate, reducing it by 89% (from 0.105 g/cm 2 to 0.019 g/cm 2 ) compared to GW1. These findings suggest that graphite incorporation is a promising approach for developing more durable and efficient grinding wheels, with the optimal graphite content for balancing strength and wear being 12 wt%.