Materials Synthesis and Development

Group

Gelcasting of ceramics

Topic

Costs and improves performance gelcasting is an approach of liquid shaping where a few percents of a polymerizeable binder are added to the ceramic slurry. If a high solid loading is achieved at a low viscosity of the slurry, geometrically stable bodies are obtained with low shrinkage by pressureless casting at room temperature, consolidation by polymerization (< 80°C) and drying.

 

Advantages

 

  • Free shaping
  • Casting with low shrinkage (-> "near net shaping") reduces costs compared with pressing/"green" finishing
  • Advantageous application to advanced raw materials (< 0.2 µm) and to coarser powders
  • Reduces required sintering temperatures (250 °C compared with uniaxial pressing of 0,2 µm Al2O3-powder) -> sintering fine-grained microstructures
  • Extreme homogeneity of powder compaction and low frequency of flaws give doubled strength and Weibull modulus (> 30) of pressureless sintered bodies (without phase transformation/anisotropic grains)

 


Improved strength by gelcasting (Al2O3)

Reduced sintering temperature of gelcast alumina

 

Products and services offered

 

  • Development of processing for advanced ceramic products (sizes < 1 mm through round 100 mm)
  • Development of approaches that reduce the costs of ceramic manufacturing when inexpensive (coarser) powders are to be used
  • Investigation of alternative binder approaches (-> patent situation, -> environment, -> industrial safety)