The cold sintering process (CSP), which has recently attracted significant research attention, is an emerging technique that enables the densification of high-melting-point ceramics at temperatures far lower than those required for conventional sintering (CS) by utilizing solvent-assisted mechanisms. In this study, CSP is employed as a pretreatment strategy for 8 mol% yttria-stabilized zirconia (8YSZ) to modify the initial microstructural and interfacial state prior to high-temperature sintering. In parallel, Fe₂O₃ was introduced as a sintering aid to enhance grain-boundary diffusion during the high-temperature stage. Rather than acting as an independent densification step, CSP establishes a path-dependent initial condition that governs the subsequent densification trajectory during conventional sintering. CSP at 180 °C for 1 h under a uniaxial pressure of 200 MPa, followed by postannealing at 1200 °C for 30 min, resulted in a high relative density of 98.11% theoretical density (TD). Depending on the type of solvent, the treated samples exhibited either a high Vickers hardness (H_v = 14.99 GPa) or a high fracture toughness (K_IC = 5.56 MPa·m^1/2), reflecting differences in grain growth mode and crack-path geometry. Stage-resolved densification kinetics were directly monitored using laser dilatometry, enabling the identification of pressure-driven rearrangement, solvent-mediated consolidation, and thermally activated diffusion contributions. The results demonstrate that CSP pretreatment governs the particle packing topology and interfacial chemistry, while Fe₂O₃ addition primarily amplifies high-temperature grain-boundary diffusion. This sequential coupling establishes a mechanistic framework for path-dependent densification in CSP-assisted ceramic processing.

Field-assisted sintering technology has revolutionized material processing by integrating temperature, mechanical, electrical, and magnetic fields to achieve unprecedented densification efficiency and microstructural control. Recent advances in techniques such as hot oscillatory pressing, cold sintering, high/ultra-high pressure sintering, spark plasma sintering, ultrafast high-temperature sintering, and flash sintering have enabled the fabrication of previously unattainable materials, including ultrafine-grained ceramics, nanostructured composites, and functionally graded materials. These materials possess exceptional performances under extreme conditions, expanding applications in aerospace, electronics, energy, and biomedicine. However, the rapid development of these methods has exposed limitations in conventional sintering theory, particularly in describing mass transport and interface evolution under multi-physics coupling. This review systematically examines representative field-assisted sintering technologies and discusses their principles, equipment configurations, and application cases. By analyzing current challenges and opportunities, we aim to bridge fundamental understanding with industrial implementation, providing insights for the design and fabrication of next-generation high-performance materials.