The Study of Reaction Sequences for Formation of Solid Solution of Ceramic Material: Pb_1-2XSm_xNd_x[(Zr_0,55Ti_0,45)_1-0.02,0.01(Y_2/3,Mo_1/3),0.01 (Y_2/3,Ni_1/3)]O₃ and the Study of These Structures

Oum Keltoum Kribaa, Ahmed Boutarfaia

University of Biskra, Biskra, Algeria.
University of Ouargla, Ouargla, Algeria.

DOI: 10.4236/jmmce.2013.15034                

Abstract

This work is aimed to synthesize new type ceramic materials: Pb_1-2XSm_xNd_x[(Zr_0,55Ti_0,45)_1-0.02,0.01(Y_2/3,Mo_1/3),0.01 (Y_2/3,Ni_1/3)]O₃ of structure perovskite in the presence of the doping agents: NiO, Sm₂O₃, Y₂O₃, Nd₂O₃ and MoO₃ near the morphotropic phase boundary. These ceramics worked out by solid way, we present the preparation and the different stages of the formation reaction of the solid solution. Then we will detail the different techniques of analysis applied to this compound; we begin by the X-ray diffraction in the following by analysis spectroscopic (FTIR), analysis by scanning electron microscopy (SEM) and finally analysis by spectrometric energy dispersive (EDS). These studies help us to accumulate as much information on these materials.

Keywords

Ceramic; Microstructure; X-Ray Diffraction; Infrared Spectroscopy (FTIR)

1. Introduction

The crystallization of bulk ceramics called “bulk” type PZT is governed by sequences of reactions from three oxides PbO, ZrO₂ and TiO₂ [1,2]. These reactions are now well known. However, several studies have been made and several conclusions were drawn about the reaction sequences of formation of the solid solution PZT. There are many ways of developing piezoelectric materials that can be classified into both physically and chemically. The method of preparation is the most famous ceramic method; this method of synthesis involves reacting at high temperature (around 800˚C) a mixture of oxides. The simple ceramic method has some drawbacks: first the reaction at high temperature may cause volatilization of PbO which makes the non-stoichiometric PZT, the second disadvantage is the slow reaction, the increase in temperature accelerates the reaction because the diffusion through the solid is faster than ordinary temperature, it is important that the starting materials are well crushed to reduce the grain size they are very well blended for maximum contact area and reduce the distance of diffusion of the reagents [3].

This part of work describes the manufacturing process of new type materials:

Pb_1-2XSm_xNd_x[(Zr_0,55Ti_0,45)_1-0.02,0.01(Y_2/3,Mo_1/3),0.01 (Y_2/3,Ni_1/3)]O₃ and their reaction mechanism, all preparations were made at temperatures not exceeding 800˚C, it gives then the results of the study radio crystallographic. In this work, the main purpose is to study the reaction sequences of formation of solid solution of PZT perovskite structure in the presence of doping NiO, Sm₂O₃, Y₂O₃, MoO₃ and Nd₂O₃. We present the preparation and the different stages of the formation reaction of the solid solution. Then we will detail the different techniques of analysis applied to this compound, we begin first by X-ray diffraction, in the following by analysis spectroscopic (FTIR), analysis by scanning electron microscopy (SEM) and finally analysis by spectrometric energy dispersive (EDS). These studies help us to accumulate as much information on these materials.

Previous Work

Several studies were conducted by different researchers [4] in order to show the reactions that occur during formation of ceramics. In general the results reported in different studies show that lead titanate PbTiO₃ is the first reaction product to be formed [4-6]. However, when using a submicron ZrO₂ powder prepared chemically, the formation of PbZrO₃ is earlier than that of PT. This PZ, the intermediate product, was not observed in most other work, with the exception of Ohno et al. [6], which reveal its formation and reaction with PT to form the PZT solid solution and also Yamaguchi et al. [6] who reported the possible formation of PZ but only under certain conditions.

The reaction sequence according to some researchers: Mori et al. [7] proposed two reaction steps:

PbO + ZrO₂ + TiO₂ → (PbTiO₃ + ZrO₂)ss

(PbTiO₃ + ZrO₂ )ss → Pb (Zr_1-x, Ti_x)O₃

Speri [8] proposed a three step process:

PbO + TiO₂ → PbTiO₃

PbTiO₃ + PbO + ZrO₂ → (PbO)ss

(PbO)ss + PbTiO₃ + ZrO₂ → Pb (Zr_1-x, Ti_x)O₃

(PbO)ss is a solid solution of tetragonal ZrO₂ containing PbO and PbTiO₃.

Hankey and Biggers [9] presented a reaction sequence consistent with Speri, but at different temperatures for each reaction step. Kingon, Terblanche and Clark [8] proposed a process of homogenization; they confirmed the formation of PbO ss in special experimental conditions, the final step in a reaction intermediate of PZT rich in PbTiO₃ PZT with rich PbZrO₃.

Matsio and Sasaki [1] were proposed:

PbO + TiO₂ → PbTiO₃

PbTiO₃ + PbO + ZrO₂ → PbTiO₃ + (PZ_xT_1-x)

PbTiO₃ + (PZ_xT_1-x) → PZT Biggers and Venkataramani [10] reported the reaction sequence for two sources of ZrO₂ synthesized and commercial a different reaction sequence occurred which depends on the ZrO₂ used. ZrO₂ synthesized gives the formation of an intermediate phase PbZrO₃ and training of PZT at 500˚C. ZrO₂ the introductory commercial formation of a phase webmail PbTiO₃ and the formation of PZT to 800˚C. Chandratreya [11] has reported on the reaction mechanisms of the formation of PZT solid solution. He found that the PbTiO₃ forms between 450˚C and 600˚C and the PZT is formed above 700˚C against any PbZrO₃ formation was detected.

2. Experimental Procedure

The synthesis of a new ceramic material (Table 1):

Pb_1-2XSm_xNd_x[(Zr_0,55Ti_0,45)_1-0.02,0.01(Y_2/3,Mo_1/3), 0.01(Y_2/3,Ni_1/3)]O₃.

From a mixture of oxide is mainly in a few steps: The amount of starting materials required for the synthesis is calculated and then weighed and mixed with acetone for 6 h for homogenization. In later dried at 100˚C in an oven for 12 h. The powder of the initial mixture is manually ground with a glass mortar for 4 h, and then the powder is compacted in the form of pellets 2 g mass. The pellets obtained are brought to the calcinations at temperatures of about 600˚C, 700˚C, 750˚C and 800˚C in a programmable oven and under an ambient atmosphere with a heating rate of 2˚C/min to a temperature maintained constant for two hours. Cooling the resulting materials is slow. No weight change was observed.

3. Results and Discussion

3.1. Analysis by “X-Ray Diffraction”

The various diagrams of X-ray diffraction were obtained using a Bruker-AXS D8 diffractometer installed at the Laboratory of what RX (University of Biskra. ALGERIA) equipped with a copper anticathode. In order to have a monochromatic radiation, the device is equipped with a monochromator which selects the wavelength corresponding to the Kα radiation of copper: 1.5405 A. To perform the measurements, the voltage applied by the generator is 40 kV and the current is 40 mA. The diffractograms are recorded at room temperature, and 2 theta between 10˚ and 90˚.

The diffraction pattern of the powder mixed oxides uncalcined (room temperature). This chart shows the characteristic lines of basic oxides PbO, ZrO₂ and TiO₂ without secondary phases that indicate the absence of any reaction between these oxides during milling. The doping oxides are in very small quantities in the initial mixture; no characteristic peak appears on this diagram.

Figures 1-4 show the X-ray diffraction pattern of the

Table 1. Composition of: B1-B2-B3-B4-B5.

Figure 1. X-ray diffraction diagram of the mixture calcined at 600˚C.

Figure 2. X-ray diffraction diagram of the mixture calcined at 700˚C.

Figure 3. X-ray diffraction diagram of the mixture calcined at 750˚C.

Powder mixed oxides calcined at 600˚C, 700˚C, 750˚C and 800˚C respectively.

Figure 5 shows the X-ray diffraction pattern of the sample B₂ sintered at 1100˚C, 1150˚C and 1180˚C.

Conflicts of Interest

The authors declare no conflicts of interest.

References

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