CO2LiquidGefüge

CO2LiquidGefüge is a term used in materials science to describe the characteristic microstructure of a material after processing in the presence of liquid carbon dioxide. The concept emphasizes how CO2 as a processing medium can influence the arrangement of grains, phases and pores, yielding a distinctive liquid CO2–induced gefüge.

Formation and mechanisms: Densification, impregnation, solvent action, or foaming caused by controlled depressurization can drive redistribution of solutes, plasticization of polymers, and creation or modification of pore networks. In polymer systems, dissolved CO2 reduces glass transition temperature and increases molecular mobility, enabling cellular or porous structures. In porous ceramics or metals, CO2 can promote pore formation or alter diffusion paths, thereby affecting the overall microstructure.

Characteristics: The resulting microstructure may exhibit refined porosity, oriented porosity, or altered boundaries between phases, often detectable by scanning electron microscopy, X-ray computed tomography, and porosimetry.

Applications and research: The term is used mainly in niche discussions of CO2-based processing routes, including polymer foaming, composite manufacturing, and high-pressure impregnation. It helps describe the structural outcomes of processing in CO2 environments rather than specifying a single chemical mechanism.

Critique and scope: CO2LiquidGefüge is not a widely standardized term and remains descriptive, varying in interpretation across studies. Researchers emphasize documenting processing conditions to connect exposure to liquid CO2 with observed microstructural features.