scholarly journals Temperature Dependence of Mechanical, Electrical Properties and Crystal Structure of Polyethylene Blends for Cable Insulation

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1922 ◽  
Author(s):  
Lunzhi Li ◽  
Lisheng Zhong ◽  
Kai Zhang ◽  
Jinghui Gao ◽  
Man Xu
Keyword(s):  
High Temperature ◽  
Electrical Properties ◽  
Temperature Dependence ◽  
Elevated Temperatures ◽  
Breakdown Strength ◽  
Temperature Stability ◽  
Xrd Analysis ◽  
Insulation Material ◽  
Cable Insulation ◽  
Polyethylene Blends

There is a long-standing puzzle concerning whether polyethylene blends are a suitable substitution for cable-insulation-used crosslinking polyethylene (XLPE) especially at elevated temperatures. In this paper, we investigate temperature dependence of mechanical, electrical properties of blends with 70 wt % linear low density polyethylene (LLDPE) and 30 wt % high density polyethylene (HDPE) (abbreviated as 70 L-30 H). Our results show that the dielectric loss of 70 L-30 H is about an order of magnitude lower than XLPE, and the AC breakdown strength is 22% higher than XLPE at 90 °C. Moreover, the dynamic mechanical thermal analysis (DMA) measurement and hot set tests suggest that the blends shows optimal mechanical properties especially at high temperature with considerable temperature stability. Further scanning electron microscope (SEM) observation and X-ray diffraction (XRD) analysis uncover the reason for the excellent high temperature performance and temperature stability, which can be ascribed to the uniform fine-spherulite structure in 70 L-30 H blends with high crystallinity sustaining at high temperature. Therefore, our findings may enable the potential application of the blends as cable insulation material with higher thermal-endurance ability.

Temperature Dependence and High-Temperature Stability of the Annealed Ni/Au Ohmic Contact to p-Type GaN in Air

2015 ◽  
Vol 45 (4) ◽  
pp. 2087-2091 ◽  
Author(s):  
Shirong Zhao ◽  
Heather McFavilen ◽  
Shuo Wang ◽  
Fernando A. Ponce ◽  
Chantal Arena ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Dependence ◽  
Ohmic Contact ◽  
Temperature Stability ◽  
High Temperature Stability ◽  
P Type

High-Temperature Dielectric Materials for Electrical Energy Storage

2018 ◽  
Vol 48 (1) ◽  
pp. 219-243 ◽  
Author(s):  
Qi Li ◽  
Fang-Zhou Yao ◽  
Yang Liu ◽  
Guangzu Zhang ◽  
Hong Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Energy Storage ◽  
Power Systems ◽  
Oil And Gas ◽  
Elevated Temperatures ◽  
Temperature Stability ◽  
Electrical Energy ◽  
Dielectric Materials ◽  
Future Research ◽  
Capacitive Energy Storage

The demand for high-temperature dielectric materials arises from numerous emerging applications such as electric vehicles, wind generators, solar converters, aerospace power conditioning, and downhole oil and gas explorations, in which the power systems and electronic devices have to operate at elevated temperatures. This article presents an overview of recent progress in the field of nanostructured dielectric materials targeted for high-temperature capacitive energy storage applications. Polymers, polymer nanocomposites, and bulk ceramics and thin films are the focus of the materials reviewed. Both commercial products and the latest research results are covered. While general design considerations are briefly discussed, emphasis is placed on material specifications oriented toward the intended high-temperature applications, such as dielectric properties, temperature stability, energy density, and charge-discharge efficiency. The advantages and shortcomings of the existing dielectric materials are identified. Challenges along with future research opportunities are highlighted at the end of this review.

High Temperature Performance of Coiled Glass Capacitors

2012 ◽  
Vol 2012 (HITEC) ◽  
pp. 000192-000198 ◽  
Author(s):  
Eugene Furman ◽  
Amanda Baker ◽  
Steve Perini ◽  
Mohan Monoharan ◽  
Douglas Kushner ◽  
...  
Keyword(s):  
High Temperature ◽  
Dielectric Breakdown ◽  
Breakdown Strength ◽  
Temperature Stability ◽  
Sodium Content ◽  
Flat Panel Display ◽  
High Temperature Stability ◽  
Thin Glass ◽  
High Dielectric ◽  
Power Capability

Alkali-free flat panel display glass is produced in large quantity and has excellent electrical insulating properties at high temperature. Aluminum borosilicate glass with alkaline-earth modifier has low sodium content and low dielectric loss (tan δ <0.1 at 250°C), high dielectric breakdown strength (109 V/m) and excellent high temperature stability. In addition, roll-to-roll processing of thin glass sheet has been demonstrated and glass capacitors that are configured in a coil. Excellent high power capability of these glasses was confirmed by analytical, finite element, and finite difference modeling. The modeling work indicates that a combination of hybrid electrode design and effective heat loss at the interface can further extend power capability of glass capacitors. Alkali-free glass is an ideal candidate material for high temperature capacitors.

Stability of Nanometer-Thick Layers in Hard Coatings

MRS Bulletin ◽  
2003 ◽  
Vol 28 (3) ◽  
pp. 169-172 ◽  
Author(s):  
Scott A. Barnett ◽  
Anita Madan ◽  
Ilwon Kim ◽  
Keith Martin
Keyword(s):  
High Temperature ◽  
Elevated Temperatures ◽  
Temperature Stability ◽  
Hexagonal Wurtzite Structure ◽  
Thin Layers ◽  
Hard Coatings ◽  
High Temperature Stability ◽  
The Stability ◽  
Hardness Values ◽  
Thick Layers

AbstractThis article reviews two topics related to the stability of hard coatings composed of nanometer-thick layers: epitaxial stabilization and high-temperature stability. Early work on nanolayered hard coatings demonstrated large hardness increases as compared with monolithic coatings, but it was subsequently found that the layers interdiffused at elevated temperatures. More recently, it has been shown that nanolayers exhibit good stability at elevated temperatures if the layer materials are thermodynamically stable with respect to each other and are able to form low-energy coherent interfaces. This article discusses metal/nitride, nitride/nitride, and nitride/boride nanolayers that exhibit good high-temperature stability and hardness values that are maintained (or even increase) after high-temperature annealing. Epitaxial stabilization of nonequilibrium structuresin thin layers is a well-known phenomenon that has been applied to hard nitride materials. In particular, AlN, which crystallizes in the hexagonal wurtzite structure in bulk form, was stabilized in the rock-salt cubic structure in nitride/nitride nanolayers (e.g., AlN/TiN). These results and the current understanding of epitaxial stabilization in hard nanolayers are discussed.

High Temperature Oxidation and Corrosion of Silicon-Based Non-Oxide Ceramics

1999 ◽  
Vol 122 (1) ◽  
pp. 13-18 ◽  
Author(s):  
H. Klemm ◽  
M. Herrmann ◽  
C. Schubert
Keyword(s):  
High Temperature ◽  
Elevated Temperatures ◽  
Microstructural Analysis ◽  
Temperature Stability ◽  
Ambient Air ◽  
High Temperature Stability ◽  
Temperature Oxidation ◽  
Sic Ceramics ◽  
Silicon Based

The present study is focussed on the oxidation behavior of nonoxide silicon-based ceramics. Various Si3N4 and SiC ceramics were examined after long term oxidation tests (up to 5000 h) at 1500°C in ambient air. The damage mechanisms were discussed on the basis of a comprehensive chemical and microstructural analysis of the materials after the oxidation tests. The diffusion of oxygen into the material and its further reaction in the bulk of the material were found to be the most critical factors during long term oxidation treatment at elevated temperatures. However, the resulting damage in the microstructure of the materials can be significantly reduced by purposeful microstructural engineering. Using Si3N4/SiC and Si3N4/MoSi2 composite materials provides the possibility to improve the high temperature stability. [S0742-4795(00)00301-X]

REFRACTALOY 70

Alloy Digest ◽  
1961 ◽  
Vol 10 (8) ◽  
Keyword(s):  
High Temperature ◽  
Elevated Temperatures ◽  
Temperature Stability ◽  
Heat Treating ◽  
High Temperature Stability ◽  
Nickel Chromium ◽  
Temperature Performance ◽  
Westinghouse Electric Corporation ◽  
Oxidation Resistant ◽  
Westinghouse Electric

Abstract REFRACTALOY 70 is a super heat and oxidation resistant alloy containing high percentages of nickel, chromium, cobalt and molybdenum. It has an exceedingly low creep rate at elevated temperatures and shows marked high temperature stability. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: Co-2. Producer or source: Westinghouse Electric Corporation. Originally published July 1953, revised August 1961.

SMITHS Ti-6Al-2Sn-4Zr-2Mo-Si

Alloy Digest ◽  
2021 ◽  
Vol 70 (12) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Titanium Alloy ◽  
High Temperature ◽  
Creep Resistance ◽  
Elevated Temperatures ◽  
Temperature Stability ◽  
High Strength ◽  
Heat Treating ◽  
High Temperature Stability ◽  
Alpha Titanium

Abstract Smiths Ti-6Al-2Sn-4Zr-2Mo-Si is a near-alpha titanium alloy that was developed for use at elevated temperatures. It exhibits high strength and toughness, excellent creep resistance, and high temperature stability at temperatures up 550 °C (1020 °F). This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting, heat treating, and joining. Filing Code: Ti-185. Producer or source: Smiths Metal Centres Limited.

The Staebler-Wronski Effect and the Thermal Equilibration of Defect and Carrier Concentrations

1994 ◽  
Vol 336 ◽  
Author(s):  
R.M.A. Dawson ◽  
C.M. Fortmann ◽  
Y.M. Li ◽  
C.R. Wronski
Keyword(s):  
High Temperature ◽  
Fermi Level ◽  
Temperature Dependence ◽  
Amorphous Silicon ◽  
Elevated Temperatures ◽  
Free Carrier ◽  
Annealed State ◽  
Thermal Equilibration ◽  
Staebler Wronski Effect ◽  
Substrate Temperatures

ABSTRACTLight induced degradation of intrinsic Amorphous silicon (a-Si:H) is investigated as a function of temperature. Previous work described an equilibrium framework for the high temperature behavior of dangling bonds defects (DB) 11]; and the temperature dependence of the annealed state photo, σPH, and dark, σD, conductivities of a series of intrinsic a-Si:H Materials deposited over a range of substrate temperatures, 200°C < Ts < 380°C [2]. These results are extended to the light degraded state where elevated temperatures provide for equilibration of the free carrier and DB concentrations. For the equilibrium, light degraded state, both σD and σPH, decrease compared to the annealed state while the ratio, σD/σPH remains unchanged. Relationships between the ratio [DB+]/[DB] and the Fermi level are derived from the equilibrium framework.

scholarly journals Enhanced High-Temperature DC Dielectric Performance of Crosslinked Polyethylene with a Polystyrene Pinning Structure

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1234 ◽  
Author(s):  
Liang Cao ◽  
Lisheng Zhong ◽  
Yinge Li ◽  
Kai Zhang ◽  
Jinghui Gao ◽  
...  
Keyword(s):  
High Temperature ◽  
Direct Current ◽  
Elevated Temperatures ◽  
Breakdown Strength ◽  
Crosslinking Agent ◽  
Special Design ◽  
Insulation Materials ◽  
High Voltage Direct Current ◽  
Dielectric Performance ◽  
Test Temperature Range

In this paper, we propose a method on improving direct current (DC) dielectric performance by designing a polystyrene (PS) pinning crosslinked polyethylene (XLPE) for the application of insulation materials on high voltage direct current (HVDC) extruded cable. Electrical experimental results show that the addition of PS (1–5 phr, parts per hundreds of resin) can significantly reduce DC conductivity and increase DC breakdown strength of XLPE in the test temperature range of 30–90 °C. Microstructure investigation shows PS distributed as particles could participate in the formation of a crosslinking network with the help of a crosslinking agent, thus forming a polymer pinning structure at the interface between XLPE and PS. It is believed that such a special design strengthens the structure of XLPE, which leads to the improved DC dielectric performance at elevated temperatures. Our findings may contribute a new solution for developing HVDC cable insulation materials.

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