Dielectric materials are important electrical materials that enable charge storage and control. Functional dielectric materials refer to the dielectric materials that can interact or mutual convert the energy of light, electricity, heat, force, magnetism. High dielectric constant materials are widely used in power equipment and electronic devices in the fields of power engineering, aerospace, and new energy because of their good energy storage characteristics and dielectric properties. With the development of power equipment and electronic devices the miniaturization and portable development are rapidly developing, and urgent requirements are imposed on the development of capacitors with large capacity and high energy storage density. This paper proposes a method to improve the dielectric constant and temperature stability of barium titanate-based ceramics by combining tricritical effects and relaxation Properties. The highlight is based on the barium titanate-based ceramic system (Ba1-xCax)(Ti1-ySny)O3, changing the doping ratio of calcium and tin, constructing a three-dimensional map of dielectric constant, and determining the tricritical points of the (Ba1-xCax)(Ti1-ySny)O3 system that are Ba(Ti0.89Sn0.11)O3、(Ba0.95Ca0.05)(Ti0.89Sn0.11)O3 、(Ba0.9Ca0.1)(Ti0.89Sn0.11)O3、(Ba0.84Ca0.16)(Ti0.89Sn0.12)O3、(Ba0.78Ca0.22)(Ti0.88Sn0.12)O3 and (Ba0.75Ca0.25)(Ti0.88Sn0.12)O3. The Tf of all the components of ceramic (Ba1-xCax)(Ti1-ySny)O3value was programmed by Matlab. In this paper, a three-dimensional phase diagram of ceramic (Ba1-xCax)(Ti1-ySny)O3 is constructed, and the projection of the three-dimensional phase diagram in the xy plane is used to clearly find the position of the tricritical points and the relaxation surface. A synergistic improvement in the dielectric constant and temperature stability of the barium titanate ceramics is achieved, and a new dielectric material with optimized performance is obtained. In this paper, the functional properties of high dielectric ceramic (Ba1-xCax)(Ti1-ySny)O3 were measured, including ferroelectric properties, energy storage properties, stain, electrocaloric properties and piezoelectric properties. It is found that the piezoelectric coefficient of (Ba0.9Ca0.1)(Ti0.89Sn0.11)O3 is 117 pC/N at 30°C; the strain decreases rapidly with the increase of temperature, and increases rapidly with the increase of electric field strength. As the doping of calcium the strain decreases, the temperature stability does not change much. At 30°C, the electric strain of (Ba0.78Ca0.22)(Ti0.88Sn0.12)O3 is 7.6%; the average storage density of (Ba0.78Ca0.22)(Ti0.88Sn0.12)O3 is 120.4 mJ/ cm3, and the coefficient of variation is only 2.2%, much lower than other ceramic samples, which means that the temperature stability of (Ba0.78Ca0.22)(Ti0.88Sn0.12)O3 is also very good; at electric field strength of 80kV/cm and 25°C, the maximum ΔT value of ceramic Ba(Ti0.89Sn0.11)O3 is 0.75°C.
I materiali dielettrici sono materiali elettrici importanti che consentono la conservazione e il controllo della carica.I materiali dielettrici funzionali si riferiscono ai materiali dielettrici che possono interagire o convertire reciprocamente l'energia di luce, elettricità, calore, forza, magnetismo.Alti materiali costanti dielettrici sono ampiamente utilizzati nelle apparecchiature di potenza E dispositivi elettronici nei settori dell'ingegneria energetica, aerospaziale e della nuova energia a causa delle loro buone caratteristiche di conservazione dell'energia e delle proprietà dielettriche.Con lo sviluppo di apparecchiature elettriche e dispositivi elettronici la miniaturizzazione e lo sviluppo portatile si stanno rapidamente sviluppando e sono imposti requisiti urgenti Lo sviluppo di condensatori con grande capacità e densità di stoccaggio ad alta energia. Questo lavoro propone un metodo per migliorare la costante dielettrica e la stabilità della temperatura delle ceramiche a base di titanato di bario combinando effetti tricrici e proprietà di rilassamento. Il clou è basato sul sistema ceramico a base di titanato di bario (Ba1-xCax)(Ti1-ySny)O3, Modifica del rapporto drogante di calcio e stagno, costruzione di una mappa tridimensionale della costante dielettrica e determinazione dei punti tricromici del sistema Ba(Ti0.89Sn0.11)O3、(Ba0.95Ca0.05)(Ti0.89Sn0.11)O3 、(Ba0.9Ca0.1)(Ti0.89Sn0.11)O3、(Ba0.84Ca0.16)(Ti0.89Sn0.12)O3、(Ba0.78Ca0.22)(Ti0.88Sn0.12)O3 e (Ba0.75Ca0.25)(Ti0.88Sn0.12)O3. Il Tf di tutti i componenti di ceramica (Ba1-xCax)(Ti1-ySny)O3 value è stato programmato da Matlab.In questo documento, viene costruito un diagramma di fase tridimensionale di ceramica (Ba1-xCax)(Ti1-ySny)O3, E la proiezione del diagramma di fase tridimensionale nel piano xy viene utilizzata per individuare chiaramente la posizione dei punti tricritici e la superficie di rilassamento.Un miglioramento sinergico della costante dielettrica e della stabilità della temperatura delle ceramiche di titanato di bario viene raggiunto, e Si ottiene un nuovo materiale dielettrico con prestazioni ottimizzate. In questo documento sono state misurate le proprietà funzionali della ceramica dielettrica alta (Ba1-xCax)(Ti1-ySny)O3, tra cui proprietà ferroelettriche, proprietà di conservazione dell'energia, colorazione, proprietà elettrocaloriche e proprietà piezoelettriche. Si trova che il coefficiente piezoelettrico di (Ba0.9Ca0.1)(Ti0.89Sn0.11)O3 è 117 pC/N a 30°C; I ceppi rapidamente con l'aumento della temperatura e aumentano rapidamente con l'aumento dell'intensità del campo elettrico.Come il drogaggio del calcio diminuisce la tensione, la stabilità della temperatura non cambia molto. A 30°C, la tensione elettrica di (Ba0.78Ca0.22)(Ti0.88Sn0.12)O3 è 7.6%, la densità media di stoccaggio di (Ba0.78Ca0.22)(Ti0.88Sn0.12)O3 è 120.4 mJ/cm3 e il coefficiente di variazione è solo del 2.2%, molto più basso di altri campioni di ceramica, il che significa che anche la stabilità della temperatura di (Ba0.78Ca0.22)(Ti0.88Sn0.12)O3 è molto buona; Alla potenza del campo elettrico di 80 kV/cm e 25°C, il valore massimo ΔT della ceramica Ba (Ti0.89Sn0.11) O3 è 0.75°C.
Dielectric property and temperature stability of high dielectric ceramics based on tricritical effect and relaxation properties
HE, YUTING
2018/2019
Abstract
Dielectric materials are important electrical materials that enable charge storage and control. Functional dielectric materials refer to the dielectric materials that can interact or mutual convert the energy of light, electricity, heat, force, magnetism. High dielectric constant materials are widely used in power equipment and electronic devices in the fields of power engineering, aerospace, and new energy because of their good energy storage characteristics and dielectric properties. With the development of power equipment and electronic devices the miniaturization and portable development are rapidly developing, and urgent requirements are imposed on the development of capacitors with large capacity and high energy storage density. This paper proposes a method to improve the dielectric constant and temperature stability of barium titanate-based ceramics by combining tricritical effects and relaxation Properties. The highlight is based on the barium titanate-based ceramic system (Ba1-xCax)(Ti1-ySny)O3, changing the doping ratio of calcium and tin, constructing a three-dimensional map of dielectric constant, and determining the tricritical points of the (Ba1-xCax)(Ti1-ySny)O3 system that are Ba(Ti0.89Sn0.11)O3、(Ba0.95Ca0.05)(Ti0.89Sn0.11)O3 、(Ba0.9Ca0.1)(Ti0.89Sn0.11)O3、(Ba0.84Ca0.16)(Ti0.89Sn0.12)O3、(Ba0.78Ca0.22)(Ti0.88Sn0.12)O3 and (Ba0.75Ca0.25)(Ti0.88Sn0.12)O3. The Tf of all the components of ceramic (Ba1-xCax)(Ti1-ySny)O3value was programmed by Matlab. In this paper, a three-dimensional phase diagram of ceramic (Ba1-xCax)(Ti1-ySny)O3 is constructed, and the projection of the three-dimensional phase diagram in the xy plane is used to clearly find the position of the tricritical points and the relaxation surface. A synergistic improvement in the dielectric constant and temperature stability of the barium titanate ceramics is achieved, and a new dielectric material with optimized performance is obtained. In this paper, the functional properties of high dielectric ceramic (Ba1-xCax)(Ti1-ySny)O3 were measured, including ferroelectric properties, energy storage properties, stain, electrocaloric properties and piezoelectric properties. It is found that the piezoelectric coefficient of (Ba0.9Ca0.1)(Ti0.89Sn0.11)O3 is 117 pC/N at 30°C; the strain decreases rapidly with the increase of temperature, and increases rapidly with the increase of electric field strength. As the doping of calcium the strain decreases, the temperature stability does not change much. At 30°C, the electric strain of (Ba0.78Ca0.22)(Ti0.88Sn0.12)O3 is 7.6%; the average storage density of (Ba0.78Ca0.22)(Ti0.88Sn0.12)O3 is 120.4 mJ/ cm3, and the coefficient of variation is only 2.2%, much lower than other ceramic samples, which means that the temperature stability of (Ba0.78Ca0.22)(Ti0.88Sn0.12)O3 is also very good; at electric field strength of 80kV/cm and 25°C, the maximum ΔT value of ceramic Ba(Ti0.89Sn0.11)O3 is 0.75°C.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/148972