Preparation and Dielectric Property of Al2O3 Surface Coating Modified BaTiO3/Polyimide Composite Film

2014 ◽  
Vol 908 ◽  
pp. 63-66
Author(s):  
Ya Jun Wang ◽  
Xiao Juan Wu ◽  
Chang Gen Feng

Polyimide (PI) was chosen as the matrix of the composite, barium titanate/polyimide (BT/PI) nanocomposite films were prepared by in situ polymerization. In order to improve the dispersion and the physical-chemical properties of BT surface, barium titanate was modified by Al2O3coating and modified BT/PI nanocomposite films were prepared. The prepared modified BT was characterized by X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM), and the dielectric properties of the composites were characterized in detail. It was shown that surface modification with Al2O3is the chemical process and there were new substances forming. When BT was modified by 10 wt% Al2O3, the dielectric constant of the composite film was 18.96 (103Hz), the loss tangent 0.005, breakdown strength 70 MV·m-1, energy storage density 0.41 J·cm-3. The dielectric constant of BT modified by Al2O3is decreased while the dielectric strength of the modified BT/PI composite film is increased.

2013 ◽  
Vol 815 ◽  
pp. 93-98 ◽  
Author(s):  
Ya Jun Wang ◽  
Xiao Juan Wu

Polyimide (PI) was chosen as the matrix of the composites, barium titanate/polyimide (BT/PI) nanocomposite films were prepared with in-situ polymerization. The morphology of the samples was obtained by SEM. The factors affecting the dielectric properties are discussed. When the mass fraction of BT is 70%, the dielectric constant will be 19.32, and loss 0.00254 (at 103 Hz). The optimal solvent content and ultrasonic time were 9.2 ml and 30 min respectively. TG analysis shows that the film is stable below 500°C. The AC breakdown strength were 42 MV·m-1 and 64 MV·m-1 for 70% BT/PI and 60% BT/PI respectively, and corresponding energy storage density were 0.17 J·cm-3 and 0.30 J·cm-3 respectively.


Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 322 ◽  
Author(s):  
Minghua Chen ◽  
Wenqi Zhou ◽  
Jiawei Zhang ◽  
Qingguo Chen

Polymeric materials have many applications in multiple industries. In this paper, silicon nitride nanoparticles (Si3N4) were incorporated into a polyimide (PI) matrix to obtain composite films via the in situ polymerization method. The Si3N4 nanoparticles were consistently scattered in the composites, and the thickness of PI/Si3N4 films was around 50 µm. The effects of nanoparticle content on the dielectric constant, loss tangent and breakdown strength were simultaneously studied. A 3 wt.% doped PI/Si3N4 film revealled excellent dielectric properties, a dielectric constant (ε) of 3.62, a dielectric loss tangent (tanδ) of 0.038, and a breakdown strength of 237.42 MV/m. The addition of Si3N4 formed an interface layer inside PI, resulting in a large amount of space charge polarization in the electric field. The space charge of materials from the microscopic point of view was analyzed. The results show that there are trapenergy levels in the composites, which can be used as a composite carrier center and transport channel, effectively improving the performance of a small amount of nanoparticles film.


2021 ◽  
pp. 095400832199352
Author(s):  
Wei Deng ◽  
Guanguan Ren ◽  
Wenqi Wang ◽  
Weiwei Cui ◽  
Wenjun Luo

Polymer composites with high dielectric constant and thermal stability have shown great potential applications in the fields relating to the energy storage. Herein, core-shell structured polyimide@BaTiO3 (PI@BT) nanoparticles were fabricated via in-situ polymerization of poly(amic acid) (PAA) and the following thermal imidization, then utilized as fillers to prepare PI composites. Increased dielectric constant with suppressed dielectric loss, and enhanced energy density as well as heat resistance were simultaneously realized due to the presence of PI shell between BT nanoparticles and PI matrix. The dielectric constant of PI@BT/PI composites with 55 wt% fillers increased to 15.0 at 100 Hz, while the dielectric loss kept at low value of 0.0034, companied by a high energy density of 1.32 J·cm−3, which was 2.09 times higher than the pristine PI. Moreover, the temperature at 10 wt% weight loss reached 619°C, demonstrating the excellent thermostability of PI@BT/PI composites. In addition, PI@BT/PI composites exhibited improved breakdown strength and toughness as compared with the BT/PI composites due to the well dispersion of PI@BT nanofillers and the improved interfacial interactions between nanofillers and polymer matrix. These results provide useful information for the structural design of high-temperature dielectric materials.


2012 ◽  
Vol 2012 (1) ◽  
pp. 000609-000616
Author(s):  
Beihai Ma ◽  
Manoj Narayanan ◽  
Shanshan Liu ◽  
Sheng Tong ◽  
U. (Balu) Balachandran

Ceramic film capacitors with high dielectric constant and high breakdown strength are promising for use in advanced power electronics, which would offer higher performance, improved reliability, and enhanced volumetric and gravimetric efficiencies. We have grown lead lanthanum zirconate titanate (PLZT) on nickel foils and platinized silicon (PtSi) substrates by chemical solution deposition. A buffer layer of LaNiO3 (LNO) was deposited on the nickel foils prior to the deposition of PLZT. We measured the following electrical properties for PLZT films grown on LNO buffered Ni and PtSi substrates, respectively: remanent polarization, ≈25.4 μC/cm2 and ≈10.1 μC/cm2; coercive electric field, ≈23.8 kV/cm and ≈27.9 kV/cm; dielectric constant at room temperature, ≈1300 and ≈1350; and dielectric loss at room temperature, ≈0.06 and ≈0.05. Weibull analysis determined the mean breakdown strength to be 2.6 MV/cm and 1.5 MV/cm for PLZT films grown on LNO buffered Ni and PtSi substrates, respectively. Residual stress analysis by x-ray diffraction revealed compressive stress of ≈-520 MPa in the ≈2-μm-thick PLZT grown on LNO buffered Ni foil, but a tensile stress of ≈210 MPa in the ≈2-μm-thick PLZT grown on PtSi substrates.


2017 ◽  
Vol 07 (01) ◽  
pp. 1750007 ◽  
Author(s):  
Gang Liu ◽  
Wentao Jiang ◽  
Jingyong Jiao ◽  
Li Liu ◽  
Ziyang Wang ◽  
...  

Ba[Formula: see text]Sr[Formula: see text]TiO3 ceramics with or without ZnO have been prepared by traditional solid state reaction method. The XRD analysis showed that the doped Zn[Formula: see text] ions diffused into the BST crystal lattice, resulting in the variation of dielectric properties. Especially the dielectric constant at Curie point decreased with doping ZnO content when it is lower than 0.5[Formula: see text]mol%. Due to the promotion of sintering, doping ZnO can enhance the density of ceramics but increase grain size. However, ZnO is a kind of semiconductor and can lead to the decrease in electrical breakdown strength value.


2014 ◽  
Vol 556-562 ◽  
pp. 371-374
Author(s):  
Kai Yan ◽  
Xiao Xu Liu

Polyamides (PI)-matrix composite films with inorganic nanoTiO2 have been fabricated by employing in situ polymerization. Before addition, TiO2 particles were firstly modified with coupling agents (KH550). The electric breakdown strength and micromorphology of hybrid films were characterized and investigated. Results indicated that nanoTiO2 particles were homogeneously dispersed in the PI matrix for the addition of coupling agents and the electric breakdown strength of PI/TiO2 composite films with KH550 were better than unmodified PI composite film. The breakdown field strength and tensile modulus of PI composite film with the inorganic content of 5 wt% were 200.1 (KV/mm). So the using coupling agent can effectively improve the compatibility and the homogenous dispersion of nanoTiO2 particles in PI matrix. Meanwhile, the procedure described here offers an effective and simple method to produce PI/TiO2 with excellent electrical needed for future application in electrical engineering field.


2016 ◽  
Vol 09 (01) ◽  
pp. 1650006 ◽  
Author(s):  
Junli Wang ◽  
Shengli Qi ◽  
Yiyi Sun ◽  
Guofeng Tian ◽  
Dezhen Wu

A three-phase composite film was produced by inserting multi-walled carbon nanotubes (MWCNTs) and BaTiO3 nanoparticles into polyimide (PI). The combination of in-situ polymerization and water-based preparation involved in the experiment ensured fillers’ homogeneous dispersion in the matrix, which led to flexible shape of the composite films. The dielectric properties of composite films as a function of the frequency and the volume fraction of MWCNTs were studied. Such composite film displayed a high dielectric constant (314.07), low dielectric loss and excellent flexibility at 100[Formula: see text]Hz in the neighborhood of percolation threshold (9.02 vol%) owing to the special microcapacitor structure. The experimental results were highly consistent with the power law of percolation theory.


1996 ◽  
Vol 446 ◽  
Author(s):  
Bang Hung Tsao ◽  
Sandra Fries Carr ◽  
Joseph A. Weimer

AbstractBaTiO3 films prepared by RF sputtering was studied for capacitor applications. Some films produced have a capacitance storage of 0.85 μF/cm2, a high resistivity of 1014 ω‐cm, and a low dissipation factor of 0.005. The dielectric constant of these BaTi03 films were approximately 10 to 30, which is superior to that of the typical polymer film capacitor and had little dependence on frequency. However the breakdown strength of BaTi03 was approximately 5MV/meter. The theoretical breakdown strength of BaTi03 is reported to be as high as 200MV/m. The processing parameters of BaTi03 films must be optimized to obtain the potential benefit of the BaTi03.


2018 ◽  
Vol 921 ◽  
pp. 91-98
Author(s):  
Ming Yu Zhang ◽  
Li Zhu Liu ◽  
K.S. Hui

Polyimide films with Al2O3composite layers were prepared by KOH solution surface hydrolysis, ion exchange and heat treatment. Scanning electron microscope (SEM), atomic force microscopy (AFM), X-ray diffractometry (XRD), thermo gravimetric analyzer (TGA), breakdown voltage tester, high frequency pulse voltage machine were performed to characterize the micromorphology, thermal stability, mechanical properties, electric breakdown strength, and corona resistance time of composite films. Results indicated that the thermal properties of the composite film are better than the original film. The corona resistance time of the composite film was longer than that of the pristine film. The composite film had the longest corona resistance time and reached 101.2min while the KOH treatment time was 90min.


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