By partially substituting Sr for Pb in ceramic lead titanate zirconate compositions near the morpho‐tropic boundary, dielectric constants greater than 1300 can be obtained along with planar couplings of about 0.50. Calcium also raises the dielectric constant, but the planar coupling level is considerably lower than that obtained with Sr. Other effects noted with Sr are a lowering of the Curie temperature, a shift in the morphotropic boundary toward the rhombohedral side, and a decrease in the distortion from cubic symmetry. In addition, Sr was found to be effective as a fluxing agen