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1、Zhu Xiaoxing,Piezoelectric Transformers,Contents,BackgroundPrinciple of Piezoelectric TransformersExamples and analysisConclusion,Piezoelectric Transformers,Piezoelectricity: A brief of history,Piezoelectricity derives from the Greek word “piezein” = to press.,1880,1939,1917,First human contact: “St
2、one Age”: use of flint”, a variety of quartz, to produce fire by creating a mechanical impact or friction. Before the invention of matches this material continued being used as a lighter knocking it against iron.,Pierre and Jacques Curie discovered the direct (1880) and the inverse effects (1881) in
3、 quartz crystals.,during WW I, Paul Langevin developed a quartz-based transducer to generate and detect acoustic waves in water. SONAR and ULTRASONICS,The US Armed Services made the decision to make large scale use of “crystal control” in military communication systems. During the WW II the US alone
4、 used about 50million quartz crystal elements.,Piezoelectric Transformers,Piezoelectricity: A brief history,1946,1965,1985,Piezoelectric effect is found in Barium Titanate.,Japanese commercial enterprises began to reap the benefits of steady application and materials development work.,The commercial
5、 success of the Japanese efforts has attracted the world-wide interest for this technology and spurred a new effort to develop successful piezoceramic products.,Ceramics,Piezoelectric Transformers,Piezoelectric Transformers,Advantages of piezoelectric transformers,High conversion efficiencySimple st
6、ructureHigh step-up ratio Stable and long service life Compact Size and Light weight,Piezoelectric Transformers,Drive part,Power part,Vin,Vout,P,T,P,Piezoelectric Transformers,Piezoelectric Transformers,Properties of Piezoelectric Material,D.C= dielectric constantKp = electromechanical coupling fact
7、orQm= mechanical quality factorTc= curie temperature,Piezoelectric Transformers,Properties of Piezoelectric Material,PNW-PMN-PZT,Pb(Ni1/2W1/2)O3 Pb(Mn1/3Nb2/3)O3 Pb(ZrxTiy)O3,Pb1-aSra(Ni1/2W1/2)0.02(Mn1/3Nb2/3)b(ZrxTiy)1-0.02-bO3,Piezoelectric Transformers,Preparation,+0.5wt%PbO+0.3wt%Fe2O3+0.25wt%C
8、eO2,Pb1-aSra(Ni1/2W1/2)0.02(Mn1/3Nb2/3)b(ZrxTiy)1-0.02-bO3,Raw materials,Acetone-milled,Calcination,CIP,Sinter,products,Piezoelectric Transformers,Piezoelectric Transformers,Piezoelectric Transformers,Piezoelectric Transformers,Piezoelectric Transformers,TCFr,One of the important parameter that piez
9、oelectric transformer are required is good stability of piezoelectric properties.,temperature coefficient of resonant frequency of nearly zero is preferable.,Piezoelectric Transformers,Piezoelectric Transformers,Piezoelectric Transformers,Piezoelectric Transformers,Properties of Piezoelectric Materi
10、al,PNW-PMS-PZT,Pb(Ni1/2W1/2)O3 Pb(Mn1/3Sb2/3)O3 Pb(Zr1/2Ti1/2)O3,Pb0.95Sr0.05(Mn1/3Sb2/3)x(Ni1/2W1/2)y (Zr1/2Ti1/2)zO3,Piezoelectric Transformers,Piezoelectric Transformers,Piezoelectric Transformers,Incorporation of Mn2+ into B-site of perovskite structured morphotropic phase boundary (MPB) composi
11、tion stabilizes rhombohedral phase against tetragonal one.,Piezoelectric Transformers,SEM photographs of the fractured surface of the sintered specimens with 6 mol% PMS as the different the content of PNW: (a) 1 mol% PNW, (b) 2 mol% PNW, (c) 3 mol% PNW, (d) 4 mol% PNW.,Piezoelectric Transformers,Wit
12、h the content of PMS increased, r decreased and tan increased gradually, because more oxygen vacancies would be generated to balance the charge.,Piezoelectric Transformers,When the content of PNW was 3 mol%, r and tan decreased gradually with the content of PNW increased.,Piezoelectric Transformers,
13、With the content of PMS increased, Kp decreased and Qm increased.,Piezoelectric Transformers,When the content of PNW was 3 mol%, kp decreased with the amount of PNW increased. When content of PNW was 3 mol%,Kp increased.,Piezoelectric Transformers,Conclusion,How to get a high performance materials?,Composition,Analysis and compare,High performance materials,Thank you,
