Effects of a combined supercritical extraction/thermal cycle on binder removal cycle time, yield, residual carbon, and defect formation in multilayer ceramic capacitors

In the fabrication of multi-layer ceramic capacitors (MLCs), organic blends of binder and plasticizer are often utilized to aid in the forming and handling of ceramic green bodies. However, these organic constituents must be removed before the green body may be sintered into a dense component. Typically the binder is thermally decomposed in air, but as the size and binder loading of the MLC increases, the time required for binder removal may last up to several days in order to avoid introducing defects into the green body. Furthermore, thermal decomposition may leave a carbon residue within the dielectric which can modify the electrical properties and sintering behavior of the MLC. In this work, a combined cycle consisting of a supercritical extraction cycle (SCE) followed by a thermal cycle (TC), was used to remove binder from green multilayer ceramic capacitors. The dielectric was barium titanate and the binder consisted of poly(vinyl butyral) plasticized with phthalates. Supercritical extraction of approximately