Chayka E. Deformation process investigation of fine oxide powders by cold isostatic pressing for high-strength ceramics fabrication

The subject is the oxide ceramics manufacturing process based on implementation of cold isostatic pressing route for powder compacts fabrication. The object is determination of the compaction parameters such as to form a microstructure ensuring high performance of sintered ceramics suitable for structural applications. The approach consists in both theoretical model construction (joint solution of the equilibrium, plasticity, and yielding equations) and experimental studies (measurements of hydrostatic density, three-point bending strength; microstructure investigation using electron microscopy. It is shown that densification of ultra-fine aggregated powders during cold isostatic pressing proceeds in five stages. A mathematical model of a powder material densification in the vicinity of the large intergranular pore is developed. Effects of shear cohesion factor and internal friction factor on powder densification process at pressing, compact and ceramics properties are established. Fields of application: ceramic processing, powder metallurgy.