Casting methods

Wet-forming methods are characterized by the direct consolidation of the green body from a homogeneous suspension with optimally dispersed powder particles. This type of shaping method – also called colloidal shaping method – is particularly preferred for ceramic powders in the nanometer or sub-micrometer range in order to use the advantages of ultrafine powders in terms of microstructure and properties.
Conventional slip casting is a widespread and cost-effective shaping method for the production of complex shaped, large-sized components made of advanced ceramics. Pressure slip casting is an established method and has been used for sanitary and table ware for many years. In the field of advanced ceramics pressure slip casting is only used for the production of complex shaped, large-size parts made of low-price raw powders in large quantities.

In gel-casting the green body is consolidated by polymerization of a monomer solution. Using this method, components of any shape and with a high level of properties can be produced.
All mentioned wet-forming methods can also be applied for the production of porous ceramics and composites.

 

Products and services offered

 

• Development of aqueous and non-aqueous suspensions with high solids conent for wet-forming methods based on oxide and non-oxide ceramic powders
  
• Detailed rheological characterization of ceramic slurries
  
• Electrokinetic characterization of aqueous suspensions (working group Powder and Suspension Characterization)
  
• Production of complex components by slip casting or gel-casting

 

Examples and references

 

• Large-sized crucibles and plates from alumina and reaction-bonded silicon nitride by slip casting
  
• Pressure slip casting of sub-micrometer alumina with the result of improved microstructure and properties in comparison with dry pressed materials based on the same raw powder
  
• Development of tailored dispersing agents and specific powder modification for aqueous silicon nitride suspensions
  
• Gel-casting of thick-walled silicon nitride parts and nano-zirconia samples