Patent ID: 6723673
Filing Date: 2004-04-20
Classification: B32B,C04B,H01G

Abstract:
A dielectric ceramic start powder comprising:a. at least ninety weight percent essentially pure barium titanate powder having an average particle size of from 0.2 to 1.2 microns; b. from 0.2 to 2.5 weight percent of a flux selected from the group consisting of barium lithium borosilicate flux, zinc lithium borosilicate flux, and mixtures thereof; c. from 0.05 to 0.3 weight percent of MnCO3; d. a grain growth inhibitor selected from the group consisting of niobium compounds Nb2O5, BaNb2O6, CaNb2O6, MgNb2O6, LiNbO3, and mixtures thereof such that a weight percent of Nb2O5 ranges from 0.4 wt % to 1.50 wt %, and tantalum compounds, and mixtures thereof, such that a weight percent of Ta2O5 ranges from 0.66 wt % to 2.50 wt %, and a mixture of molar equivalents of the niobium and tantalum compounds; and, e. from 0.4 to 1.4 weight percent of an additive selected from the group consisting of a rare earth oxide, yttrium oxide, a combination of rare earth oxides, and a combination of yttrium oxide and rare earth oxides, such that ions of the rare earth oxide, ions of the yttrium oxide, ions of the combination of rare earth oxides, and ions of the combination of rare earth oxides and yttrium oxide have an average ionic radius of about 0.97 angstroms.