Mechanistic design of porous self-lubricating grinding wheels with integrated internal cooling: Role of PMMA and nickel-coated MoS₂ composites in machining enhancement

This study significantly advances grinding wheel technology by synergistically integrating poly (methyl methacrylate) (PMMA)-induced porosity with nickel-coated molybdenum disulfide (Ni-coated MoS₂) lubrication. This integration addresses the critical trade-off between cooling efficiency and structural durability in grinding nickel-based superalloys. Mechanistic analysis indicates that sintering at 910°C allows nickel to suppress copper-sulfur interfacial embrittlement while promoting titanium carbide (TiC) bonding reinforcement. This process achieves an optimal flexural strength of 72.63 MPa with 5 % PMMA-induced interconnected porosity. The pore network enhances coolant retention, resulting in an 18.6 % reduction in grinding temperature through a combination of internal cooling and lubricant film dissipation. Tribological optimization at 6 % Ni-coated MoS₂ content reduces friction coefficients by 22.7 % under a 100 N load due to lattice distortion effects, while also mitigating abrasive adhesion through controlled solid lubricant release. Comparative grinding trials demonstrate transformative performance: surface roughness decreases by 30.45 % as porous channels retain grinding debris, thereby suppressing three-body abrasion. Additionally, compressive residual stresses increase twofold due to reduced thermal gradients. Crucially, the self-sharpening mechanism extends wheel longevity by maintaining the integrity of abrasive protrusions compared to conventional wheels, as validated by reduced microcracking and spalling observed in post-test microscopy. These advancements establish a material-process paradigm in which controlled porosity generation synchronizes thermomechanical stress management with tribological regulation, achieving simultaneous improvements in surface quality, thermal control, and grinding wheel lifespan for machining applications.