Low temperature co-fired ceramics (LTCC) for the insulation coating of high temperature electrical conductors

A low temperature co-fired ceramic (LTCC) with a general formation HZnO-10MoO3 was developed for dielectric and high temperature insulation applications. Powders of the LTCC material were synthesized via a solid state route; ceramic suspensions for dip coating were prepared by mixing 5 to 20vol% of the LTCC powders, polyvinyl butyral (PVB) based binder, solvents and other organic additives. Processing parameters for dip coating included the ceramic content of starting suspension, withdrawal rate and firing temperature. These were optimized through trial experiments on Ni discs prior to coating of wire specimens. After process optimization, the dip-coated, co-fired wire exhibited an insulation thickness of 40.3 µm and a sufficiently high breakdown voltage of 798 V, demonstrating its potential for high temperature machine winding applications.