Ceramic Slip - Barium Titanate Slurry for Multilayer Ceramic Capacitor Manufacturing
The green sheet casting must be of uniform thickness and free of oversized particles, voids and gel-like deformable contaminants. Large particle contaminants can occur due to certain variable aspects of the production process for making barium titanate from barium carbonate and titanium dioxide, as well as from agglomeration of the BT slurry itself.
The presence of large particles or agglomerates can affect the relative shape of the layers, leading to a non-uniform electric field and the occurrence of electrostriction. This can lead to unacceptable audible vibration from an MLCC used in AC service, a condition that can ultimately cause device failure.
BaTiO3 (BT) is the typical ceramic material used for dielectric layers. BT powder is mixed with binders, solvents and some additives. Typical solvents are toluene, MEK, ethanol, acetone, IPA, xylene, etc. The components of the ceramic slip will vary depending on the recipe being used. The BT slurry is dispensed as a film onto a PET support. Pall Corporation has successfully implemented proprietary filtration technologies for both classification and gel retention of ceramic slip forming the green sheet.
Filtration Products for Ceramic Slip (BT Slurry)Pall's Profile® Star filters and Poly-Fine® XLD filters, unique hybrids of pleated and depth filter construction, have become increasingly important for thin layer and high viscosity applications, where the high differential pressures cannot be addressed by traditional depth filters.
For submicron filtration of the most advanced, thinnest layer green sheet being developed, Pall Corporation’s Ultipor® GF-HV glass microfiber filter is available in removal ratings as fine as 0.1 micron.