Studied ceramics have been sintered from mixtures of powders including a tetragonal tungsten bronze (TTB) phase K0.2Sr0.4NbO3 (KSN), two perovskite phases, Pb(Mg1/3Nb2/3)O3 (PMN) and Pb(Fe½Nb½)O3 (PFN), and a lithium salt in a small amount. We studied the whole relaxor/TTB composition diagram. We had shown in previous studies that these ceramics could exhibit either type I or type II dielectric behaviors, depending on both the composition and the sintering schedule. We present here our last results in the perovskite side of the diagram with regard to a fine analysis of such ceramics sintered at 1240°C in an oxygen flow. In particular, results obtained with X-ray Photoemission Spectroscopy (XPS), Scanning Electron Microscopy (SEM) associated with EDS analysis and X-ray diffraction have been correlated with 1 kHz dielectric measurements from-50°C to 150°C and ferroelectric characterizations.