Dissertation > Excellent graduate degree dissertation topics show

Study on the Lead-free Low Loss Y5P-152 High Voltage Ceramics

Author: ChenYaDong
Tutor: RanJunGuo;ZuoChunHua
School: Sichuan University
Course: Materials Engineering
Keywords: low dielectric loss lead-free ceramics SrTiO3 doping modification technics dielectric properties
CLC: TQ174.75
Type: Master's thesis
Year: 2006
Downloads: 32
Quote: 0
Read: Download Dissertation


Environmental issues are critical for everybody around the world. Usingenvironment-friendly material is of fundamental significance for environmentprotection. Low dielectric loss lead-free ceramics get increasingly more atten-tion due to their environment-friendly properties.By strictly controlling every step in the preparation process and applyin-g analytical techniques such as SEM, the effect of Sr-Bi-Ti ceramics prepar-ation on dielectric properties was studied. Combining different stir grind ti-me and rotational speed, sintering temperature and soaking time, the bestset of parameters was determined. It was found that too long stir grind tim-e or too high rotational speed can not decrease the size of ceramic particlesbut bring more impurities into the ceramic and then worsen its dielectricproperties. On the other hand, too short stir grind time or too low rotationa-1 speed may result in oversized particles. Both sintering temperature and so-aking time have a mutually restricting and supplementary relationship. Highsintering temperture should be combined with a short soaking time whilelow sintering temperature should be combined with a long soaking time. Th-e optimized sintering temperature is between 1190℃~1220℃and the opti-mized soaking time is 2 hours.Futhermore, this thesis studied how the amount of Bi2O3·TiO2 affected the dielectric properties and proposed a mechanism behind this effect. Itwas found that Bi2O3·TiO2 can dramatically increase the dielectric constantof ceramics if it is lower than 10mol%. Higher amount of Bi2O3·TiO2 candecrease the dielectric constant and increase the dielectric loss. Also, by lo-wering the Sr/Ti ratio Bi2O3·TiO2 incorporation can decrease the sintering te-mperature. Doping modification research indicate that mixing small amountof MgTiO3 can make the ceramics structure more tightly, reduce defect, incr-ease the dielectric constant and decrease the variation of dielectric constantagainst temperature. Mixing Dy2O3 and MnO2 can decrease the size of cer-amic particles. Dy2O3 can increase dielectric constant if it’s between 0.6wt%~0.8wt%. MnO2 can reduce the dielectric loss and increase break downvoltage of capacitor materials if its concentration is about 0.3 wt%. Combin-ed doping of Nb2O5, SiO2 between 0.1wt%~0.2wt% can prevent the sizeof ceramic crystals to be too large while lower the variation of dielectricconstant against temperature.Based on a series of experiment on different recipe and preparation tec-hnology, we finally get the ceramics with a dielectic constantεr≥1450,dielectric loss tgδ≤0.15%, break down voltage Eb≥10KV/mm[DC], Eb≥4KV/mm [AC] are prepared, and the temperature dependence of dielectric co-nstant can well satisfy the Y5P specification, [(C-30℃-C25℃</sub>/C25℃, (C85℃-C25℃/C25℃]≤±10%. This result is on the advanced level domestically andwill set up a good starting point for the independent development of a newgeneration of lead-free low loss high voltage ceramic capacitors.

Related Dissertations

  1. Modification of Thermosetting Resins by High Performance Liquid Crystalline Epoxy Resin,TQ323.5
  2. Microwave Dielectric Resonator Ceramics of High-Q Value for the 3G Mobile Communication Base Stations,TQ174.756
  3. PVDF -based nano- particle composite dielectric properties outfield Regulation,O482.4
  4. Study on Processing and Properties of High Power and Receiving-projecting Dual-purpose Piezoelectric Ceramic,TM282
  5. RF magnetron sputtering HfO_2 the electrical properties of thin films and the temperature of the weak ferromagnetism,O484.1
  6. Interface layer on the CMN / CT laminated film structure and dielectric properties,O484.1
  7. Spark Plasma Sintering of BaTiO3 Based Composite Ceramics,TQ174.756
  8. The transparent transistors SrTiO_3 transparent film Preparation and Properties of,O484.1
  9. Study of the MLCC new dielectric material in the high - temperature -stable,TQ174.754
  10. Mechanism and Preparation of Cordierite Powder Synthesized by Microemulsion-Sol Gel Technique,TB383.3
  11. Blade fuse base material preparation and co-fired with fuse unit study,TM563
  12. NBT-KBT-100x Preparation and characterization of piezoelectric thin,TM22
  13. Field induced nano hybrid polyimide dielectric properties and microstructure of,TB383.1
  14. PP / MMT nanocomposites crystal morphology and dielectric properties of,TB383.1
  15. Preparation and temperature stability of the KNLNT -based lead-free piezoelectric ceramics,TM282
  16. Research on Moisture Diffusion and Impregnation Characteristics of Vegetable Oil-paper Insulation,TM855
  17. Carbon fiber / fluorinated polymer composites research,TB332
  18. Preparation and Property Improvement for CaCu3Ti4O12 Giant Dielectric Constant Thin Film,O484.1
  19. A Study on Doping Modification of Ultra-fine (Ba,Sr)TiO3 Series Capacitor Ceramics,TM28
  20. Study of Medium Temperature Sintering of X8R BaTiO3-based Ceramics,TQ174.1
  21. Nano-Al/BaTiO3/Epoxy Three-Phase Composites as Embedded Dielectrics,TB333

CLC: > Industrial Technology > Chemical Industry > Silicate > Ceramic Industry > Ceramics > Industrial ceramic
© 2012 www.DissertationTopic.Net  Mobile