What is the difference between a castable ceramic cement and a potting cement?
A castable ceramic cement has low viscosity, enabling casting or pouring in moulds of complex shapes. It is formulated to limit segregation, to ensure effective dimensional reproducibility, and to produce a ceramic part. Potting cement is used to encapsulate or fix components in an assembly.
At Final Advanced Materials castable cements are optimised for the manufacture of parts (final density 2.0–3.0 g/cm³), while potting cements are designed to prioritise adhesion in assemblies (housings, resistor overmoulding, etc.).
For foundry moulds Final Advanced Materials produces alumina, silicon carbide, silica or zirconia-based cements, which are suited for temperatures between 1,200 and 2,200°C. Zirconia formulations are particularly suitable if a very high resistance to chemicals is required. Alumina cements have better mechanical resistance (>40 MPa in compression). SiC cement is a very good option for molten metal casting, launders, crucibles or nozzles. The choice depends on the cast metal and the temperature (e.g.: aluminium ~700°C, steel >1,500°C) and the thermal shock resistance.
The ceramic casting cements produced by Final Advanced Materials have standard compression resistances of 10 to 40 MPa, depending on the formulation and porosity. Thermal shrinkage is generally low, reducing internal stresses and cracking. Dense alumina-based formulations offer the best mechanical performance, while more insulating systems have a lower resistance, but reduced thermal conductivity (<0.15 W/m·K).
The choice depends mainly on the temperature and the mechanical stresses.
Final Advanced Materials' high-temperature epoxy resins are generally limited to temperatures ranging between 150 and 350°C, have a good mechanical resistance (typical sheer-stress 10–30 MPa) and a degree of elasticity.
However, the ceramic cements produced by Final Advanced Materials can be used up to 2,200°C, depending on the grade (alumina, zirconia, silicon carbide, silica). They have excellent temperature resistance, but remain fragile (brittle behaviour, no elasticity).
Environmental constraints are important factors which must also be taken into account.