# Electrophysical Properties of PZT-Type Ceramics Obtained by Two Sintering Methods
## 1 Introduction
Traditional sintering methods for PZT-type ceramics include pressureless sintering and hot sintering [24; 25]. Each of these methods has its distinctive advantages and disadvantages. Along with technological progress, new methods of sintering PZT-type ceramics were introduced, such as microwave sintering [26; 27], laser sintering [28; 29], isostatic sintering, hot pressing [30], and plasma spark sintering [31; 32]. These advanced techniques allow for better control of the sintering process and also provide the ability to produce PZT-type ceramics with high microstructure uniformity and higher density. The selection of the appropriate method of sintering PZT ceramics and the optimization of sintering parameters are crucial to obtaining the desired quality and properties of the ceramic material [33; 34; 35; 36; 37; 38; 39; 40]. In the technological process, depending on the application, PZT-type materials are obtained, e.g., in the bulk form (as ceramic material), thin or thick layers, gradient materials, and recently even use some 3D printing technologies such as selective laser sintering (SLS), binder jetting (BJT), stereo-lithography (SLA), and material extrusion (MEX) [41]. The main objective of this study was to investigate the effect of pressureless sintering (PS) and hot sintering (HP) on the basic properties of PZT-type ceramics. The PZT-type material with the general formula Pb(Zr\({}_{0.49}\)Ti\({}_{0.51}\))\({}_{0.94}\)Mn\({}_{0.021}\)Sb\({}_{0.016}\)Gd\({}_{0.012}\)W\({}_{0.012}\)O\({}_{3}\) (labeled as S) was selected for the tests. The basic composition of PZT (from the morphotropic region) was doped with Mn\({}^{4+}\), Sb\({}^{3+}\), Gd\({}^{3+}\), and W\({}^{6+}\). Scientific research conducted in the studies [42; 43; 44; 45; 46; 47; 48; 49] showed that the admixtures, as mentioned above, improve the microstructure (by increasing grain homogeneity) and affect the basic ferroelectric properties, e.g., increasing the permittivity value or reducing the dielectric loss factor. In the PZT materials, the ferroelectric hard admixture (trivalent ions, e.g., antimony Sb\({}^{3+}\), gadolinium Gd\({}^{3+}\)) causes an increase in coercive field \(E_{\mathrm{c}}\), mechanical quality factor \(Q_{\mathrm{m}}\), and a decrease in the permittivity \(\varepsilon\), dielectric loss, electromechanical coupling factor \(k_{\mathrm{p}}\), and electrical resistivity. The soft admixtures (hexavalent ion, e.g., tungsten W\({}^{6+}\)) increase permittivity \(\varepsilon\), electromechanical coupling factor \(k_{\mathrm{p}}\), elastic susceptibility \(S_{\mathrm{\sharp}}\), electrical resistivity, and reduce coercive field \(E_{\mathrm{c}}\) and mechanical quality factor \(Q_{\mathrm{m}}\). At the same time, the manganese Mn\({}^{4+}\) admixture is aimed at increasing the uniformity of grains in the sample microstructure [50]. The exploration of the influence of two sintering methods on the final parameters of the obtained PZT-type ceramics was carried out in this study. Several tests and analyses were conducted, including X-ray examinations, analysis of the surface morphology of ceramic samples using a scanning electron microscope (SEM) and energy dispersion spectroscopy (EDS), studies of ferroelectric and dielectric properties, and DC electrical conductivity.