Effect of excess PbO on the structure and piezoelectric properties of Bi-modified PbTiO3 ceramics

Effect of Alkali Elements Content on the Structure and Electrical Properties of (K0.48Na0.48Li0.04)(Nb0.90Ta0.04Sb0.06)O3 Lead‐Free Piezoelectric Ceramics

“…Although it has been known that, because of the high volatility, the alkaline elements may evaporate during the long high‐temperature sintering process, there is little work studying the effects of the resulting compositional fluctuations on the properties of the KNN and KNN‐based ceramics, 6 or reporting the use of excess alkaline elements for compensating the loss. For lead‐based materials (especially, PZT), it has been shown that the nonstoichiometric composition resulting from the PbO volatilization has adverse effects on the ferroelectric and piezoelectric properties of the ceramics 7–11 . A certain amount of Pb or PbO in excess to the basic composition is usually added, especially in preparing sol–gel‐derived ceramic films, for compensation and hence for improving the properties 7–11 .…”

The Effect of Excess PbO on Crystal Structure, Microstructure and Dielectric Properties of (Pb0.50Sr0.50)TiO3Ceramics

“…The opposing trend is observed in the values of the dielectric loss (tan δ), which are listed in Table1. It is well known that, increased density and decreased porosity are the dominant factors controlling the dielectric constant [14,21]. So, the dielectric constant decreased in the sample excess PbO > 1 wt.% with increasing porosity and decreasing density.…”

“…The increases and decreases in the densities of the PST ceramics are due to the decrease and increase in porosity. The rearrangement of the particles begins most probably at the melting temperature of PbO (890 • C) and takes place rapidly [14]. This process becomes more intense if a sufficient liquid phase is present to allow an easy rearrangement of the grains.…”

“…The addition of excess PbO is one of the techniques developed to counteract this problem. For example, the optimum density of PLZST [12], PBT [14], PBZ [15], PZT [16] ceramics can be improved by the addition of excess PbO. From a survey of the literature, the effect of excess PbO on PST ceramics prepared via the solid-state reaction method had not been observed yet.…”

Effect of lead content on the structure and piezoelectric properties of hard type lead titanate–zirconate ceramics

“…The usual practice is to protect the samples during sintering either by covering them with a blanket of a similar presintered powder able to create a rich PbO atmosphere during sintering 7 or by tightly sealing the crucibles in which the samples are sintered. Another way is to add small amounts of PbO in excess to the basic composition [8][9][10][11][12] or to use sintering aids to lower, to some extent, the sintering temperature. [13][14][15][16][17][18][19][20][21][22] Unfortunately, though helpful, neither way can provide a satisfactory solution to the problem but from the practical point of view the best approach still remains the control of stoichiometry by adding a certain amount of PbO before or after calcining, as a means to find experimentally the optimum processing conditions for a given material.…”