Journal of Zhengzhou University (Engineering Edition) Studies on Properties of MgO, Y2O3, MnO2 Doped PZT Ultrasonic Piezoelectric Ceramics He Xiaoyong, Lu Hongxia, Zhang Rui, Xu Hongliang, Li Yuanzhang (College of Materials Engineering, Zhengzhou University, Zhengzhou 450002, Henan, China), measured the samples of different components Density, volume shrinkage, microhardness, and insulation resistance before polarization of some samples gave the sample a maximum density of 6.8346 g/cm3 and a maximum volume shrinkage of more than 40%. The results showed that the preburn temperature was 820±20°. C is more suitable, and the addition of Mg) can improve the sintering performance of the sample.
1 Introduction to the test Brief introduction: He Xiaoyong (19 - Southern Province Xu Ml people Zheng cM graduate student. Allrightsreserved. Ultrasound is frequency greater than 20000Hz vibration, it has the same refraction, reflection phenomenon, can form standing wave, in addition to the mechanical, Secondary effects such as cavitation, thermal and chemical, etc. Since the 1950s, ultrasonic technology has been widely used in fields such as power ultrasound, non-destructive testing, underwater detection and medical care, especially in the past ten years, especially in acoustic motors and sonochemistry. Harmonic suspension and other aspects show a broad application prospects.
Piezoelectric ceramics is an important ultrasonic generating material. For a film with a thickness of 〖 that is coated with electrodes on both sides, it is polarized along the thickness direction. When the applied frequency coincides with the natural frequency of the piezoelectric film, the piezoelectric film resonates. Ultrasound, frequency is. In many fields of application, the application of power type piezoelectric ceramics has become increasingly widespread, such as piezoelectric actuators, piezoelectric vibration feeders, various types of piezoelectric transformers, high-power ultrasonic welding technologies, and ultrasonic CVD processes that have rapidly emerged in recent years. Ultrasonic IC welding technology in integrated circuit production and high-power (tens of kilowatts) ultrasonic cleaning projects that are compatible with nuclear power plants. All of these applications are based on high-power, high-performance piezoceramics and require piezo-electric sheets to have: 1 high electromechanical coupling coefficient and large quality factor M) = (also/) 2; 2 lower Electrical loss and mechanical loss; 3 higher sensitivity; 4 can withstand high power and excellent performance stability. Therefore, in order to meet the practical application of the material's piezoelectric performance requirements, additives such as MgOY2O3 and Mn2 are usually added to the basic formula. They improve the quality factor of the material and improve the piezoelectric, dielectric and time stability of the material. Has a significant role. In this experiment, appropriate trace additives were added to the PZT secondary twin phase Pb0.95Sr0.05 (Z.0.535Ti0.465)3, and the physical and electrical properties of the sample were measured to obtain excellent samples.
1 Experimental work 1.1 Materials and Formulations The 3 groups of formulations, namely the basic production process of piezoelectric ceramics samples, are a kind of pre-firing, forming, and sintering. The raw materials are weighed by the optical balance according to the chemical weight percentage, accurate to the fourth place after the decimal point; the ball mill uses a planetary ball mill, the rotation speed is 400~600r/h, the milling time is 4h, the material: ball: water is 1:2:2.5 After drying, it is pre-fired and kept at each temperature for 680C and 820C for 0.5h to synthesize PbTi3 and main crystal phase Pb(0.535.4S)3. It will help to sinter into porcelain, eliminate water and carbon dioxide in raw materials, and reduce firing. Shrinkage, conducive to control the external dimensions; further ball milling after granulation, the binder is 5% PVA, sieved to get about 50rtn pellets, and then press molding on the press, the pressure is 30~50MPa, holding time 60s; firing temperature is 1200 1240°C, 1280°C and 1320 holding time is 1h, and finally a sample having a diameter of about Y7mm is obtained.
2 Experimental Results and Analysis Discussion 2.1. Discussion of Bulk Density The ratio of constant weight to volume measured after drying at ±5°C reflects the compactness of the sample and the level of mechanical strength. Table 1 shows the samples before and after sintering. density.
Table 1 Sample Density After Sintering Sample Number Temperature Plant C Description: Samples 1-4 are Sample 1 samples, Samples 5-8 are Formula 2 samples, and Samples 9-12 are Formula 3 samples.
From Table 1, it can be seen that the density of the sample of Formula 1 is larger than that of Formulation 2 and Formula 3, but the decreasing tendency is also faster. This is due to the addition of MgO, which acts as a solvent for the equivalent substitution, improves the sintering conditions, increases the density and compactness, but the firing range narrows; and Y2O3 and Mn2 are added as unequal substitutions. A large amount of lead vacancies, ie, Y23->2Ypb+30+Pb, resulted in a decrease in the density. The samples of the three formulations sintered at 1240C had the highest density, indicating that the optimum firing temperature was near this.
2.2 Discussion of Shrinkage Ratio A series of physical and chemical changes occur in the ceramic sample during sintering. Pb34 decomposes to form PbO and 2. With the increase of temperature, PbO and Ti2 and Zi2 generate PbTi3 and a small amount of PbZi3, respectively. The following reactions take place: : (a large number) to carry out the material migration, from the place where the saturated vapor pressure is high to the place where the saturated vapor pressure is small, and finally grow into a complete crystal grain, the size is about 2. 5m. Acoustic Yu Ruifang. Sensor Theory 丨 M. Beijing: Aviation Industry Press, He Lianxing, Li Chengen. Research on Modification of High Power PZT Material . Gong Liu Kang. Principles of Ceramic Technology 丨 M. Guangzhou: South China University of Technology is printed on Yongjia. University Chemistry Handbook 丨 M. Jinan: Shandong University Press, Liu Meidong, Xu Yuchun. Piezoelectric Ferroelectric Materials and Devices丨 M. Wuhan: Huazhong University of Science and Technology Press, 1990.
