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In this paper, the development of a relaxor ferroelectric ceramics preparation techniques, both traditional oxide mixing (CMO Act), the secondary synthesis method (CPM Act) and wet chemical method (CPM method) characteristics of semi-chemical method (SCH law ); SCM prepared a group of the perovskite structure of PMN the PNN group, PFW group and PMW-PNN-PT-based ceramics; systematically studied the preparation process, excessive reactant components, the perovskite phase stabilizer of PbTiO 3 (PT) and the modifier MnO 2 ceramic phase structure, microstructure and dielectric properties; optimization of the process of SCM prepared. SCM method and CMO law, CPM process difference, and SCM prepared PMN-PT and PFW powder, solid-state reaction mechanism. Study representative of sintering aids on the sintering temperature of PMN-PT ceramics, phase composition, microstructure and dielectric properties were studied. SCM method and a core - shell structure combining PMW-PNN-PT ceramic having a chemical composition and structure unevenness \formation mechanism and improve the the dielectric temperature stability of the mechanism of the preparation process to meet the the X7R characteristics of ceramic. PMN-PT system to study the precursor of the reactants, such as Pb (AC) 2 , Mg (NO 3 ) 2 , Ti (OC 4 H 9 ) 4 instead of PbO, MgO, TiO 2 on the pre-burning powder calcium perovskite phase formation. The results showed that: a soluble magnesium acetate or magnesium nitrate solution instead of MgO, at the molecular level to improve the dispersibility of MgO, and formed at a low temperature decomposition the new eco MgO having a high reactivity, can promote pyrochlore opposing perovskite The mineralogical transformation activation TiO 2 component synergies Tetrabutoxide obtained similar results with the chemical method. The SCM Preparation of PMN-PT powder burn process is 800 ℃ ~ 850 ℃, 2h ~ 4h, the sintering process at 950 ℃ to 1200 ℃, for 1h ~~ h. PNN-PT system, the use of the the SCM law in not to add stabilizer PT and an excess of NiO can be obtained pure perovskite structure ceramics; powder of the system burn-in process for the 850 ° C for 2h ~~ h sintering process 1100 ℃ ~ 1200 ℃, 1h ~ 2h. Manganese-doped, the dielectric constant of the PNN-PT ceramic samples, although slightly reduced, but the dielectric loss of the ceramic samples is significantly reduced, a more appropriate amount of manganese-doped 0.5 (mol)%. PFW-PT system, powder burn process is 800 ℃ to 850 ℃, for 1h ~~ h sintering process to 870 ° C, for 2h ~~ h; Add the excess PbO excess Fe 2 O < sub> 3 perovskite phase content can improve PFW calcined powders and ceramics as well as the dielectric constant of the ceramic, but adding excess Fe 2 O 3 significantly increased dielectric loss. Manganese-doped favor stable PFW perovskite phase, and with the increase of the amount of manganese-doped ceramic dielectric constant first increases and then decreases dielectric loss sharp decline significantly improved resistivity and dielectric properties significantly improved, more appropriate doped manganese in an amount of 1.0 (mol)%; adding PT able to improve the stability of the PFW, with the increment of the PT content, the grain size is slightly increased, and the density is also increased, the Curie temperature of the ceramic gradually l The high diffuse phase transition gradually decreased, the dielectric constant increases gradually. SCM method CPM law process, process, calcining and sintering temperature is low, the reaction time is short; ceramic dense dielectric performance was significantly improved than CMO law and CPM method, and even in the presence of no PT, obtained pure PMN-based perovskite structure, PNN group, PFW group ceramics. Reaction mechanism for PMN-PT ceramics, the SCM method generate instability, the missing bits B pyrochlore phase Pb 3 Nb 2 O 8 , the intermediates can easily be transformed into perovskite phase; CMO generate stable pyrochlore phase Pb 3 Nb 4 O 1 4 directly with the \0. Formed by the reaction pyrochlore phase PbFeWO. . ; While puncturing is at the higher temperature, Pbbo4 continue Pbo reaction generated PBW. 0. Then Pbb. 0. Can reactivity difference and the poor dispersibility of the Fe. 0. Formed by the reaction PbFeFO. . ; Finally transformed into the perovskite structure PFW. SCM method, the reaction mechanism of the PFW state N dry T difference is that the former is formed in the intermediate phase is PbFeWO. . , In the middle of the latter phase ratio. Nb. 0. . Than, Pbo-Bi public, Ph (Cd ;/ the zw ;/. Sichuan., Ph (Cll ;/ W;;) 0., And found as PW-PT ceramic sintering aids, Pbo as sintering aids, is a liquid-phase sintering mechanism, in the late sintering, Pbo will remain in the grain surface, the dielectric properties deteriorate due to dilution of the ferroelectric phase. ratio and Bi. 0 as a composite sintering aid, compared to separate significantly improve the dielectric properties of the bands sintering aids; Ph (Cd ;/; w ;/) 03 and stare (Cll ;/, W ;/.) 0 are the perovskite structure, the former can significantly reduce PWi -PT ceramic dielectric loss, which can significantly increase the density of the ceramic samples. Cdo as sintering aids, can enter the A bit of the complex perovskite structure and replace lead, thus forming a lattice defects and promote sintering adds 2 .0 (mol)% ratio of 3.0 (mol)% of the bands (CD1 ZW;.) 0. Ph (CLL;; ZW;; Nakagawa, PbO-Bi Sin mixed sintering aid agent ( a molar ratio of 1:1:1) have reached the ideal sintering aids, the sintering temperature can be lowered to 900oC, and dielectric performance, the sample permittivity IS000 and 22000, respectively, is not less than the dielectric loss were not than 0.05 and 0.15 in the PW-PNN-PT system, when the sintering temperature is higher than 1000oC perovskite phase begin to decompose, so that the ceramic to become the \improve the temperature stability of the dielectric. preparation dielectric ceramics with high temperature stability suitable sintering temperature of 1100 ~ 1150oC; to add excess tons conducive to stable perovskite phase and improve the ceramic dielectric constant: Excess and wo. obvious The decrease in the perovskite phase content of the ceramic, the dielectric constant decreases, but favorable to the stability improvement of the ceramic \the formation mechanism of the \the result that the buffer layer W reduced enrichment of Nb, Ti, and Ph; shell
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