The Impact of Pores on Microstructure Evolution: A Phase-Field Study of Pore-Grain Boundary Interaction

Among the most important issues of today’s materials research ceramic materials play a key role as e.g. in Lithium batteries, in fuel cells or in photovoltaics. For all these applications a tailored microstructure is needed, which usually requires sintering: A pressed body of compacted powder redistributes its material and shrinks to a compact body without pores. In a very porous polycrystal, pores constrain the motion of interfaces (pore drag) and no grain growth occurs. During further sintering the number and size of pores decreases and the pore drag effect fades away. Accordingly, in the final stage of sintering grain growth emerges. This grain growth decreases the driving force for sintering and is undesirable, but hard to avoid. Since application of ceramic materials usually requires a dense and fine-grained microstructure, it is of high interest to control the interplay of remaining pores and interface migration during sintering.