scholarly journals DC Dielectric Breakdown Behavior of Thermally Sprayed Ceramic Coatings

2017 ◽  
Author(s):  
Minna Niittymäki ◽  
Tomi Suhonen ◽  
Jarkko Metsäjoki ◽  
Kari Lahti
Keyword(s):  
Electric Field ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Strong Dependence ◽  
Degradation Process ◽  
Ceramic Coatings ◽  
Alumina Coating ◽  
Dc Resistivity ◽  
Ramp Rate ◽  
Thermally Sprayed

<p>Previous studies of dielectric properties of thermally sprayed insulating ceramic coatings are focused on linearly ramped dielectric breakdown strength as well as<br />DC resistivity, relative permittivity and dielectric loss characterizations. However, reports of the effects of ramp rate or of any kind of long term stressing on the breakdown strength cannot be found in literature. The aim of this paper was to study the DC breakdown behavior of one type of HVOF sprayed alumina coating under different stresses. It can be concluded that the ramp rate of DC breakdown measurement has no remarkably influence on the breakdown strength. The breakdown behavior was also studied using step-by-step tests with two constant step voltages and step durations. The DC resistivity of the alumina coating showed strong dependence on the applied electric field. The resistivity behaved ohmicly below the field strength of ~0.5 V/μm and above ~8…12 V/μm, however, the resistivity decreased approximately three decades in the nonohmic region (0.5 V/μm --&gt;). At electric field strengths above ~25 V/μm, the degradation started in the material leading to breakdown. However, when the step duration was longer (60 min), the degradation process started already slightly below the applied field of 25 V/μm.</p>

scholarly journals Effects of Ambient Conditions on the Dielectric Properties of Thermally Sprayed Ceramic Coating

2018 ◽  
Author(s):  
M Niittymäki ◽  
B. Rotthier ◽  
K. Lahti ◽  
T. Suhonen ◽  
J Metsäjoki
Keyword(s):  
Dielectric Properties ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Thermal Spraying ◽  
Ceramic Coatings ◽  
Alumina Coating ◽  
Ambient Conditions ◽  
Coating Materials ◽  
Sprayed Coating ◽  
Thermally Sprayed

<p>Thermal spraying techniques are used to manufacture insulating coatings especially for demanding applications like fuel cells where normal insulating materials cannot be used. In electrical insulation applications, the mostly used coating materials are aluminum oxide (Al2O3), magnesium oxide (MgO) and magnesium aluminate (MgAl2O4). Dielectric properties of thermally sprayed ceramic coatings are strongly affected by ambient conditions, and in addition to this they are not well documented in the literature. In this paper the effects of environmental conditions on certain dielectric properties of a thermally sprayed coating are studied. DC resistivity as well as permittivity and losses at different frequencies at relative humidities of 20 % and 45 % at temperature of 20 °C, 40 °C and 60 °C will be reported in the paper for Al2O3 samples sprayed using HVOF (High Velocity Oxygen Fuel) technique. DC dielectric breakdown strength is also studied for the HVOF alumina coating at temperature of 20 °C and relative humidity of 20 %. Effects of ambient conditions and coating material composition are also analyzed.</p>

scholarly journals Size and temperature effects on dielectric breakdown of ferroelectric films

2020 ◽  
Author(s):  
Sheng Tong
Keyword(s):  
Energy Density ◽  
Electric Field ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Operating Temperature ◽  
Electric Energy ◽  
Ferroelectric Films ◽  
Lead Lanthanum Zirconate Titanate ◽  
Dimensional Parameters ◽  
Electric Energy Density

Abstract The paper introduces a model of dielectric breakdown strength. The model integrated thermal breakdown and defect models, representing the relationship between the electric field of ferroelectric films and dimensional parameters and operating temperature. This model is verified with experimental results of the lead lanthanum zirconate titanate (PLZT) films of various film thickness (d = 0.8 – 3 mm), electrode area (A = 0.0020 – 25 mm2) tested under a range of operating temperature (T = 300 – 400 K) with satisfying fitting results. Also learned is a relationship that the recoverable electric energy density is directly proportional to the square of breakdown electric field. This relationship is found viable in predicting the electric energy density in terms of variables of d, A, and T for the PLZT films.

scholarly journals Size and Temperature Effects on Dielectric Breakdown of PLZT Film Capacitors

2020 ◽  
Author(s):  
Sheng Tong
Keyword(s):  
Energy Density ◽  
Electric Field ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Electric Energy ◽  
Thickness Effect ◽  
Thermal Breakdown ◽  
Lead Lanthanum Zirconate Titanate ◽  
Dimensional Parameters ◽  
Electric Energy Density

Abstract The paper introduces a model of dielectric breakdown strength. The model integrated thermal breakdown and defect models, the relationship between the electric field of ferroelectric films and dimensional parameters and operating temperature (T). The thickness effect is thermal breakdown in origin, whereas the area effect is statistical in nature. This model is verified with experimental results of the lead lanthanum zirconate titanate (PLZT) films of various d (0.8 – 3 m), A (0.0020 – 25 mm2) tested under a range of T (300 – 400 K) with satisfying fitting results. Also learned is a relationship that the recoverable electric energy density is directly proportional to the square of breakdown electric field. This relationship is found viable in predicting the electric energy density in terms of variables of d, A, and T for the PLZT films.

scholarly journals Size and temperature effects on dielectric breakdown of ferroelectric films

2021 ◽  
Vol 10 (1) ◽  
pp. 181-186
Author(s):  
Sheng Tong
Keyword(s):  
Energy Density ◽  
Electric Field ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Operating Temperature ◽  
Electric Energy ◽  
Ferroelectric Films ◽  
Lead Lanthanum Zirconate Titanate ◽  
Dimensional Parameters ◽  
Electric Energy Density

AbstractThe paper introduces a model of dielectric breakdown strength. The model integrated thermal breakdown and defect models, representing the relationship between the electric field of ferroelectric films and dimensional parameters and operating temperature. This model is verified with experimental results of the lead lanthanum zirconate titanate (PLZT) films of various film thickness (d = 0.8–3 μm), electrode area (A = 0.0020–25 mm2) tested under a range of operating temperature (T = 300–400 K) with satisfying fitting results. Also learned is a relationship that the recoverable electric energy density is directly proportional to the square of breakdown electric field. This relationship is found viable in predicting the electric energy density in terms of variables of d, A, and T for the PLZT films.

scholarly journals Size and temperature effects on dielectric breakdown of ferroelectric film capacitors

2020 ◽  
Author(s):  
Sheng Tong
Keyword(s):  
Energy Density ◽  
Electric Field ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Operating Temperature ◽  
Electric Energy ◽  
Lead Lanthanum Zirconate Titanate ◽  
Dimensional Parameters ◽  
The Relationship ◽  
Electric Energy Density

Abstract The paper introduces a model of dielectric breakdown strength. The model integrated thermal breakdown and defect models, representing the relationship between the electric field of ferroelectric films and dimensional parameters and operating temperature. This model is verified with experimental results of the lead lanthanum zirconate titanate (PLZT) films of various film thickness ( d = 0.8 – 3 m m), electrode area ( A = 0.0020 – 25 mm 2 ) tested under a range of operating temperature ( T = 300 – 400 K) with satisfying fitting results. Also learned is a relationship that the recoverable electric energy density is directly proportional to the square of breakdown electric field. This relationship is found viable in predicting the electric energy density in terms of variables of d , A , and T for the PLZT films.

scholarly journals Dielectric Breakdown Strength and Energy Storage Density of CCTO-ZBS Electroceramic

2020 ◽  
Vol 596 ◽  
pp. 012006
Author(s):  
Muhammad Qusyairie Saari ◽  
Julie Juliewatty Mohamed ◽  
Muhammad Azwadi Sulaiman ◽  
Mohd Fariz Abd Rahman ◽  
Zainal Arifin Ahmad ◽  
...  
Keyword(s):  
Energy Storage ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Energy Storage Density ◽  
Dielectric Breakdown Strength ◽  
Storage Density

scholarly journals Preparation and Degradation Characteristics of MAO/APS Composite Bio-Coating in Simulated Body Fluid

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 667
Author(s):  
Zexin Wang ◽  
Fei Ye ◽  
Liangyu Chen ◽  
Weigang Lv ◽  
Zhengyi Zhang ◽  
...  
Keyword(s):  
Simulated Body Fluid ◽  
Composite Coating ◽  
Body Fluid ◽  
Composite Coatings ◽  
Degradation Process ◽  
Ceramic Coatings ◽  
Immersion Test ◽  
Substrate Material ◽  
Atmospheric Plasma

In this work, ZK60 magnesium alloy was employed as a substrate material to produce ceramic coatings, containing Ca and P, by micro-arc oxidation (MAO). Atmospheric plasma spraying (APS) was used to prepare the hydroxyapatite layer (HA) on the MAO coating to obtain a composite coating for better biological activity. The coatings were examined by various means including an X-ray diffractometer, a scanning electron microscope and an energy spectrometer. Meanwhile, an electrochemical examination, immersion test and tensile test were used to evaluate the in vitro performance of the composite coatings. The results showed that the composite coating has a better corrosion resistance. In addition, this work proposed a degradation model of the composite coating in the simulated body fluid immersion test. This model explains the degradation process of the MAO/APS coating in SBF.

scholarly journals Construction of a Three-Dimensional BaTiO3 Network for Enhanced Permittivity and Energy Storage of PVDF Composites

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3585
Author(s):  
Xueqing Bi ◽  
Lujia Yang ◽  
Zhen Wang ◽  
Yanhu Zhan ◽  
Shuangshuang Wang ◽  
...  
Keyword(s):  
Energy Storage ◽  
Polyvinylidene Fluoride ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Sol Gel ◽  
Three Dimensional ◽  
Low Dielectric ◽  
Energy Storage Properties ◽  
Discharge Energy Density ◽  
Pure Pvdf

Three-dimensional BaTiO3 (3D BT)/polyvinylidene fluoride (PVDF) composite dielectrics were fabricated by inversely introducing PVDF solution into a continuous 3D BT network, which was simply constructed via the sol-gel method using a cleanroom wiper as a template. The effect of the 3D BT microstructure and content on the dielectric and energy storage properties of the composites were explored. The results showed that 3D BT with a well-connected continuous network and moderate grain sizes could be easily obtained by calcining a barium source containing a wiper template at 1100 °C for 3 h. The as-fabricated 3D BT/PVDF composites with 21.1 wt% content of 3D BT (3DBT–2) exhibited the best comprehensive dielectric and energy storage performances. An enhanced dielectric constant of 25.3 at 100 Hz, which was 2.8 times higher than that of pure PVDF and 1.4 times superior to the conventional nano–BT/PVDF 25 wt% system, was achieved in addition with a low dielectric loss of 0.057 and a moderate dielectric breakdown strength of 73.8 kV·mm−1. In addition, the composite of 3DBT–2 exhibited the highest discharge energy density of 1.6 × 10−3 J·cm−3 under 3 kV·mm−1, which was nearly 4.5 times higher than that of neat PVDF.

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