Electrical Properties, Strength, and Structure of VK94-1 Ceramics Produced Using Spray Drying of Highly Concentrated Suspension

We have studied the electrical properties, strength, and structure of a ceramic material having the same composition as the commercially available VK94-1 ceramic. Ceramic samples have been prepared using a novel technological approach involving spray drying of a highly concentrated aqueous suspension of a mineral powder mixture with the VK94-1 composition, compaction of the resultant granulate by a combination of uniaxial semidry pressing and cold isostatic pressing, and subsequent sintering of the green compacts in air. The improved performance parameters of the materials studied are due to the good rheological properties of the granulate, which ensure an increased density of the green compacts and sintered material with a microcrystalline structure. The following properties of the material, superior to those of the commercially available VK94-1 ceramic, have been achieved: relative density, 98.7%; bending strength, 380–420 MPa, grain size in the structure of the sintered material, 1–5 μm; dielectric permittivity, 9.7; dielectric loss tangent, 3.4 × 10–4; and volume resistivity, 5.3 × 1014 Ω cm. The ceramic produced in this study can be recommended as a material for special-purpose dielectric parts.