scholarly journals Current Status of Research on the Modification of Thermal Properties of Epoxy Resin-Based Syntactic Foam Insulation Materials

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3185
Author(s):  
Zhongyuan Zhang ◽  
Xiaohan Dai ◽  
Le Li ◽  
Songsong Zhou ◽  
Wei Xue ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Epoxy Resin ◽  
Coefficient Of Thermal Expansion ◽  
Negative Thermal Expansion ◽  
Syntactic Foam ◽  
Research Field ◽  
Current Status ◽  
Insulation Materials

As a lightweight and highly insulating composite material, epoxy resin syntactic foam is increasingly widely used for insulation filling in electrical equipment. To avoid core burning and cracking, which are prone to occur during the casting process, the epoxy resin-based syntactic foam insulation materials with high thermal conductivity and low coefficient of thermal expansion are required for composite insulation equipment. The review is divided into three sections concentrating on the two main aspects of modifying the thermal properties of syntactic foam. The mechanism and models, from the aspects of thermal conductivity and coefficient of thermal expansion, are presented in the first part. The second part aims to better understand the methods for modifying the thermal properties of syntactic foam by adding functional fillers, including the addition of thermally conductive particles, hollow glass microspheres, negative thermal expansion filler and fibers, etc. The third part concludes by describing the existing challenges in this research field and expanding the applicable areas of epoxy resin-based syntactic foam insulation materials, especially cross-arm composite insulation.

Primary pyroelectric transition temperatures of binary nitrides (AlN, GaN and InN)

2019 ◽  
Vol 33 (05) ◽  
pp. 1950049
Author(s):  
Muralidhar Swain ◽  
Sushant K. Sahoo ◽  
Bijay K. Sahoo
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Negative Thermal Expansion ◽  
Polarization Field ◽  
Piezoelectric Polarization ◽  
Polarization Mechanism ◽  
Prior Literature

The primary pyroelectric transition temperature of wurtzite nitrides (AlN, GaN and InN) has been explored theoretically from their thermal properties. The spontaneous and piezoelectric polarization modifies the thermal conductivity of nitrides. The thermal conductivity [Formula: see text] as a function of temperature including and excluding the polarization mechanism predicts a transition temperature [Formula: see text] between primary and secondary pyroelectric effects. Below [Formula: see text], thermal conductivity including polarization field [Formula: see text] is lesser than thermal conductivity excluding polarization field [Formula: see text]. This is due to negative thermal expansion in binary nitrides below [Formula: see text]; however, above [Formula: see text], [Formula: see text]. [Formula: see text] is significantly contributed by piezoelectric polarization above [Formula: see text] due to thermal expansion which is the reason for the secondary pyroelectric effect. The transition temperature [Formula: see text] for AlN, GaN and InN has been predicted as 100 K, 70 K and 60 K, respectively, which fit well with the prior literature studies. This report proposes that thermal properties’ study can reveal the role of acoustic phonons in pyroelectricity.

scholarly journals Comparison of experimental and modelling results of thermal properties in Cu-AlN composite materials

2013 ◽  
Vol 61 (2) ◽  
pp. 507-514 ◽  
Author(s):  
M. Chmielewski ◽  
W. Weglewski
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Metal Matrix ◽  
Coefficient Of Thermal Expansion ◽  
Analytical Models ◽  
Matrix Composites ◽  
Pressing Method ◽  
3D Space ◽  
Automotive Electronic

Abstract Copper-based composites could be widely used in automotive, electronic or electrical industry due to their very promising thermal properties. In the present paper, Cu-AlN metal matrix composites with ceramic volume fractions between 0.1 and 0.4 were fabricated by hot pressing method in vacuum. Dependence of the coefficient of thermal expansion (CTE) and the thermal conductivity (TC) on the chemical composition of composites has been investigated. The measured values of the thermal expansion coefficient have been compared with the analytical models’ predictions. A numerical model based on FEAP 7.5 in 3D space has been used to evaluate the influence of the porosity on the thermal properties (thermal conductivity) of the composite. A fairly good correlation between the FEM results and the experimental measurements has been obtained.

scholarly journals Improvement in Mechanical and Thermal Properties of Graphite Flake/Cu Composites by Introducing TiC Coating on Graphite Flake Surface

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 519 ◽  
Author(s):  
Ren Zhang ◽  
Xinbo He ◽  
Qian Liu ◽  
Xuanhui Qu
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Hot Pressing ◽  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
Packaging Material ◽  
Graphite Flake ◽  
Mechanical And Thermal Properties ◽  
Electronic Packaging Material

In this work, TiC coating was successfully deposited on a graphite flake surface via molten salt technique, for the purpose of promoting the interfacial connection between Cu and graphite flake. Vacuum hot pressing was then employed to prepare TiC-coated graphite flake/Cu composite. The results indicate that introducing TiC coating on graphite flake surface can evidently reduce the pores and gaps at the interface, resulting in a significant improvement on the bending strength. When the TiC-coated graphite flake content is 60 vol%, the bending strength is increased by 58% compared with the uncoated one. The coefficient of thermal expansion dropped from 6.0 ppm·K−1 to 4.4 ppm·K−1, with the corresponding thermal conductivity as high as 571 W·m−1·K−1. The outstanding thermal conductivity, apposite coefficient of thermal expansion, as well as superior processability, make TiC-coated graphite flake/Cu composite a satisfactory electronic packaging material with vast prospect utilized in microelectronic industry.

Thermal Properties of Carbon/Epoxy Resin Composites Based on the Template of Artificial Sponge

2012 ◽  
Vol 560-561 ◽  
pp. 129-133
Author(s):  
Tian Chi Wang ◽  
Li Jing Chang ◽  
Ching Ping Wong
Keyword(s):  
Thermal Expansion ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Epoxy Resin ◽  
Network Structure ◽  
Coefficient Of Thermal Expansion ◽  
Resin Composites ◽  
Interpenetrating Network ◽  
High Thermal Diffusivity ◽  
Epoxy Resin Composites

Artificial sponge was used as the template to produce carbon/epoxy resin composites with interpenetrating network structure. Carbon with a network structure was first obtained by the pyrolysis of sponge. The composites were then obtained by injecting epoxy resin into the carbon. Their microstructures, thermal diffusivity, and thermal expansions were analyzed. The results show that the structure of sponge controlled the interpenetrating network structures of the carbon/epoxy resin composites. The composites exhibit a lower coefficient of thermal expansion and a high thermal diffusivity than the epoxy resin.

Study on Electrical and Thermal Properties of Epoxy Resin/Inorganic Filler Composites for the Fully Enclosed Casting Bus Bar and its Calculation of the Temperature Field

2014 ◽  
Vol 804 ◽  
pp. 191-194 ◽  
Author(s):  
Nai Kui Gao ◽  
Yi Li Wang ◽  
Wen Xi Zhang ◽  
Zhao Liu ◽  
Chi Chen ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Temperature Field ◽  
Thermal Properties ◽  
Epoxy Resin ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Room Temperature ◽  
Inorganic Filler ◽  
Study Results

This paper focused on the epoxy resin/inorganic filler composites. The electrical and thermal properties of the composites were tested and analyzed at room temperature. The influence of temperature on the thermal conductivity and thermal expansion coefficient was studied. Based on the electrical and thermal properties of the composites, the simulation model of the fully enclosed epoxy resin casting bus bar (FEERCB) was built, and the temperature field distribution of the FEERCB was calculated. T The study results showed that the volume resistivity, dielectric constant, dielectric loss factor and breakdown strength of the epoxy resin/inorganic filler composites were 1.74×1014Ω·cm, 3.44, 3.75 and 22.31 kV/mm respectively at room temperature. The thermal conductivity and thermal expansion coefficient of the composites were 2.55 W/m·K and 21.73×10-6 /°C, achieved the insulation requirements for FEERCB. In the temperature range of the test, with increasing temperature, the thermal conductivity reduced gradually, while the thermal expansion coefficient increased gradually. The simulation results showed that the FEERCB has remarkable performance on the heat dissipation and current carrying capability.

Effect of Particle Morphology on Thermal Properties of TiB2 Particle Dispersed Pure Aluminum Composites

2021 ◽  
Vol 1016 ◽  
pp. 213-217
Author(s):  
Gen Sasaki
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
Pure Aluminum ◽  
Particle Volume Fraction ◽  
Particle Dispersion ◽  
Aluminum Composites ◽  
Tib2 Particles

Particle size and distribution affect the thermal properties such as thermal conductivity, thermal expansion, and mechanical properties. In this study, TiB2 particles were used for the dispersant of pure aluminum composites because of high thermal conductivity and low thermal expansion of TiB2. Composites with different dispersibility and volume fraction of particles were prepared by spark plasma sintering. The effect of particle dispersibility in composites on thermal conductivity was estimated quantitatively by the simulation and experiments. As increasing dispersibility, the thermal conductivity was decreased and Vickers's hardness increased, but alternation for thermal conductivity was very small. With increasing volume fraction of particles, the effect of the particle dispersion on the change of the thermal conductivity increased. In addition, the empirical equation of the thermal conductivity considering dispersibility was estimated. The coefficient of thermal expansion decreased with increasing the particle volume fraction, and the experimental value quite accorded with a result provided by the rule of mixture.

Design, Preparation and Thermal Properties of (La0.4Sm0.5Yb0.1)2Zr2O7 Ceramic for Thermal Barrier Coatings

2012 ◽  
Vol 512-515 ◽  
pp. 469-473 ◽  
Author(s):  
L. Liu ◽  
Z. Ma ◽  
F.C. Wang ◽  
Q. Xu
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Rare Earth ◽  
Thermal Expansion Coefficient ◽  
Thermal Barrier Coatings ◽  
Expansion Coefficient ◽  
Phonon Transport ◽  
Thermal Barrier ◽  
Barrier Coatings

According to the theory of phonon transport and thermal expansion, a new complex rare-earth zirconate ceramic (La0.4Sm0.5Yb0.1)2Zr2O7, with low thermal conductivity and high thermal expansion coefficient, has been designed by doping proper ions at A sites. The complex rare-earth zirconate (La0.4Sm0.5Yb0.1)2Zr2O7 powder for thermal barrier coatings (TBCs) was synthesized by coprecipitation-calcination method. The phase, microstructure and thermal properties of the new material were investigated. The results revealed that single phase (La0.4Sm0.5Yb0.1)2Zr2O7 with pyrochlore structure was synthesized. The thermal conductivity and the thermal expansion coefficient of the designed complex rare-earth zirconate ceramic is about 1.3W/m•K and 10.5×10-6/K, respectively. These results imply that (La0.4Sm0.5Yb0.1)2Zr2O7 can be explored as the candidate material for the ceramic layer in TBCs system.

Evaluation of CeSZ Thermal Barrier Coatings for Diesels

2000 ◽  
Author(s):  
P.J. Huang ◽  
J.J. Swab ◽  
P.J. Patel ◽  
W.S. Chu
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Barrier Coatings ◽  
Coefficient Of Thermal Expansion ◽  
Fuel Efficiency ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Mechanical And Thermal Properties ◽  
Barrier Coatings ◽  
Spray Process

Abstract The development of thermal barrier coatings (TBCs) for diesel engines has been driven by the potential improvements in engine power and fuel efficiency that TBCs represent. TBCs have been employed for many years to reduce corrosion of valves and pistons because of their high temperature durability and thermal insulative properties. There are research programs to improve TBCs wear resistance to allow for its use in tribologically intensive areas of the engine. This paper will present results from tribological tests of ceria stabilized zirconia (CeSZ). The CeSZ was applied by atmospheric plasma spray process. Various mechanical and thermal properties were measured including wear, coefficient of thermal expansion, thermal conductivity, and microhardness. The results show the potential use of CeSZ in wear sensitive applications in diesel applications. Keywords: Thermal Barrier Coating, Diesel Engine, Wear, Thermal Conductivity, and Thermal Expansion

Effect of Interconnectivity of Nickel on Electrical and Thermal Properties of Alumina-Ni Interpenetrating Phase Composite

2011 ◽  
Vol 239-242 ◽  
pp. 2679-2682 ◽  
Author(s):  
Rub Nawaz Shahid ◽  
Bin Awais Hasan ◽  
Fahad Ali ◽  
Naeem Ul Haq Tariq
Keyword(s):  
Electrical Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Impedance Spectroscopy ◽  
Electron Spectroscopy ◽  
Coefficient Of Thermal Expansion ◽  
Optimal Combination ◽  
Percolation Limit ◽  
Scanning Electron

In this work percolation range for Al2O3-Ni interpenetrating phase composite (IPC) was studied to find the optimal combination of electrical conductivity and coefficient of thermal expansion (CTE). The impedance spectroscopy and scanning electron spectroscopy were used to study the percolation limit.

Sign in / Sign up

Export Citation Format

Share Document