The polycrystalline ceramic samples of general formula Pb1−XCaXTiO3 with X = 0.00, 0.1, 0.2 and 0.3 have been synthesized by standard high temperature solid state reaction method using high purity
oxide and carbonates. The formation of the single phase compounds have been checked by X-ray diffraction technique. The Modulated
Differential Scanning Calorimetry has been used to investigate the effect of substitution on the phase transition temperature
and the corresponding change on the enthalpy and other thermal parameters of the substituted compound/solid solutions. It
was observed that the phase transition temperature (Tc) decreases linearly with the increase of substitution concentration. The linear decrease in Tc with increase of substitution concentration may be useful for the eventual functionality of the materials for different ferroelectric
devices. The results are discussed in detail.