Processing and Thermal Properties of Cu-AlN Composites

2010 ◽  
Vol 65 ◽  
pp. 100-105 ◽  
Author(s):  
Marcin Chmielewski ◽  
Katarzyna Pietrzak ◽  
Dariusz Kaliński ◽  
Agata Strojny
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Composite Materials ◽  
Coefficient Of Thermal Expansion ◽  
Processing Parameters ◽  
Process Conditions ◽  
Pressing Method ◽  
Materials Used ◽  
Effective Transfer

Heat transfer by conduction is involved in the use of heat sinks dissipitating heat from electronic devices. Effective transfer of heat requires using materials of high thermal conductivity. In addition, it requires appropriate values of thermal expansion, matched to the semiconductor materials, high purity of materials used and good contact between bonded elements across which heat transfer occurs. The conventional materials are not able to fulfil still raising and complex requirements. The solutions of this problem could be using the composites materials, where the combinations of different properties is possible to use. This study presents the technological tests and the analysis of correlation between processing parameters and the properties of copperaluminium nitride composites. Composite materials were obtained by mixing in planetary ball mill and then densified using the sintering under pressure or hot pressing method. The microstructure of obtained composite materials using optical microscopy and scanning electron microscopy were analyzed. Coefficient of thermal expansion (CTE) and thermal conductivity (TC) were investigated depending on the process conditions.

scholarly journals A Comprehensive Review on Theoretical Aspects of Nanofluids: Exact Solutions and Analysis

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 725 ◽  
Author(s):  
Nadeem Ahmad Sheikh ◽  
Dennis Ling Chuan Ching ◽  
Ilyas Khan
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Exact Solutions ◽  
Transfer Rate ◽  
Coefficient Of Thermal Expansion ◽  
Literature Survey ◽  
Heat Transfer Characteristics ◽  
Hybrid Nanofluids ◽  
Mass Expansion

In the present era, nanofluids are one of the most important and hot issue for scientists, physicists, and mathematicians. Nanofluids have many important and updated characteristics compared to conventional fluids. The thermal conductivity, thermal expansion, and the heat transfer rate of conventional fluids are not up to the mark for industrial and experimental uses. To overcome these deficiencies, nanoparticles have been dispersed into base fluids to make them more efficient. The heat transfer characteristics through symmetry trapezoidal-corrugated channels can be enhanced using nanofluids. In the present article, a literature survey has been presented for different models of nanofluids and their solutions—particularly, exact solutions. The models for hybrid nanofluids were also mentioned in the present study. Furthermore, some important and most used models for the viscosity, density, coefficient of thermal expansion, coefficient of mass expansion, heat capacitance, electrical conductivity, and thermal conductivity are also presented in tabular form. Moreover, some future suggestions are also provided in this article.

Friction and Wearing Behaviour of Sintered Composites Made from Copper Mixed with Carbon Fibers

2015 ◽  
Vol 660 ◽  
pp. 81-85 ◽  
Author(s):  
Radu Caliman
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Composite Materials ◽  
Friction Coefficient ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Coefficient Of Thermal Expansion ◽  
Density Ratio ◽  
Point Of View ◽  
Short Carbon

This paper presents a study regarding friction and wear comportment of sintered composite materials obtained by mixture of copper with short carbon fibers. Sintered composites are gaining importance because the reinforcement serves to reduce the coefficient of thermal expansion and increase the strength and modulus. In case of composites form by carbon fiber and copper, the thermal conductivity can also be enhanced. The combination of low thermal expansion and high thermal conductivity makes them very attractive for electronic packaging. Besides good thermal properties, their low density makes them particularly desirable for aerospace electronics and orbiting space structures. Compared to the metal itself, a carbon fiber-copper composite is characterized by a higher strength-to-density ratio, a higher modulus-to-density ratio, better fatigue resistance, better high-temperature mechanical properties and better wear resistance. Varying the percentage of short carbon fibers from 7,8% to 2,4%, and the percentage of copper from 92,2% to 97,6%, five dissimilar composite materials have been made and tested from the wear point of view. Friction tests are carried out, at room temperature, in dry conditions, on a pin-on-disc machine. The friction coefficient was measured using abrasive discs made from steel 4340 having the average hardness of 40 HRC, and sliding velocity of 0,6 m/sec. The primary goal of this study work it was to distinguish a mixture of materials with enhanced friction and wearing behaviour. The load applied on the specimen during the tests, is playing a very important role regarding friction coefficient and also the wearing speed.

Thermophysical Properties of Molybdenum Copper Multilayer Composites for Thermal Management Applications

2015 ◽  
Vol 825-826 ◽  
pp. 297-304 ◽  
Author(s):  
Martin Seiss ◽  
Tobias Mrotzek ◽  
Norbert Dreer ◽  
Wolfram Knabl
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Management ◽  
Thermophysical Properties ◽  
Copper Content ◽  
Coefficient Of Thermal Expansion ◽  
Strong Anisotropy ◽  
Multilayer Composites ◽  
Properties Of Materials ◽  
Materials Used

The key properties of materials used for thermal management in electronics are thermal conductivity and the coefficient of thermal expansion. These properties can be tailored by stacking molybdenum and copper layers. Here, molybdenum copper multilayer composites with varying copper content, from 63 to 88 wt%, have been investigated. It is demonstrated, that thermal conductivity and coefficient of thermal expansion, can be adjusted by the copper content. Two flash methods for measuring the thermal conductivity are compared and the validity of the results is discussed since measurements on thin materials with strong anisotropy require a certain setup of the measurement device. For the studied compositions the thermal conductivity was determined to be between 220 to 270 W/m/K and the coefficient of thermal expansion between 6.1 to 11.5 ppm/K.

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.

Thermal Conductivity of the Diamond-Cu Composites with Chromium Addition

2011 ◽  
Vol 311-313 ◽  
pp. 287-292 ◽  
Author(s):  
Qiang Zuo ◽  
Wei Wang ◽  
Meng Sen Gu ◽  
Hai Jiang Fang ◽  
Li Ma ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Heat Conduction ◽  
Hot Pressing ◽  
Coefficient Of Thermal Expansion ◽  
High Thermal Conductivity ◽  
Electronic Components ◽  
Pressing Method ◽  
Diamond Particles ◽  
Continuous Progress

The continuous progress of the electronic industries put forward a new requirement to the electronic components that must have an excellent heat conduction performance. Thus diamond-Cu composite is developed as a high thermal conductivity and low coefficient of thermal expansion material. A vacuum hot pressing method is chosen to prepare diamond-Cu composites and the thermal conductivity of the diamond-Cu composite is researched. The effects of different contents of chromium, the size of diamond particles and the content of diamond particles on the thermal conductivity of the diamond-Cu composite are discussed. The results demonstrate that the chromium element can improve the thermal conductivity of the composites and the thermal conductivity is largest when the content of chromium is 3 percent.

Thermal Property Evaluation of Chilled Aluminum-Alumina MMC

2015 ◽  
Vol 1101 ◽  
pp. 79-82
Author(s):  
B.C. Suresh ◽  
S.B. Arun
Keyword(s):  
Thermal Expansion ◽  
Composite Materials ◽  
Thermal Property ◽  
Coefficient Of Thermal Expansion ◽  
Matrix Material ◽  
High Strength ◽  
Stir Casting ◽  
Al Alloy ◽  
Industrial Growth ◽  
Property Evaluation

Now a day’s composite materials are taking very important role in industrial growth. Composite materials are widely used in Automobiles, aerospace, submarine and also in other major fields, due to their special characteristics like light weight, high strength, stiffness, corrosion resistance. The determination of Coefficient of Thermal Expansion (CTE) of MMCs is important to aid its usage in high temperature environment as in the case of automobile combustion chamber. In these applications the stability of the composites over a long period of operation is a critical design considerationPresent work deals with the thermal property evaluation of the Al alloy / alumina metal matrix composite developed using the Stir Casting with chilling route technique. LM 26 Al alloy is being selected as the matrix material as it is a potential alloy for automotive piston applications. Al alloy / alumina MMCs was cast under end chilling technique by dispersing the reinforcement from 6 to 12 wt% the steps of 3% to study the variation in its thermal properties. At the same time chill material is also changed (Copper and MS) for different composition of MMCs cast to study the thermal behavior variations. After casting the required MMC, test specimens were prepared as per the standards to conduct thermal conductivity (K) tests and coefficient of thermal expansion (CTE) tests. Above tests were repeated for different composites containing different weight % of dispersed cast using different chills.

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

scholarly journals The Effects of Physical Properties of Fibers in Nettle Fiber/Polyester Composites on the Thermal Conductivity Coefficient

2018 ◽  
Vol 1 (1) ◽  
pp. 834-842
Author(s):  
Murat Koru ◽  
Kenan Büyükkaya
Keyword(s):  
Thermal Conductivity ◽  
Composite Materials ◽  
Physical Properties ◽  
Thermal Conductivity Coefficient ◽  
The Black Sea ◽  
Stinging Nettle ◽  
Fiber Concentration ◽  
Black Sea Region ◽  
Polyester Composites ◽  
Materials Used

The physical properties of the materials used are also important in the thermal conduction, besides many other factors. In this study, nettle fiber/polyester composites were formed using stinging nettle grown in the Black Sea region. The stinging nettle fibers used in the formation of these composites were divided into three parts as bottom, middle, and top. The physical properties (diameter, density, crystallinity) of the fibers obtained from different parts of the plant and how the increased fiber concentration affected the thermal conductivity coefficients of the composite materials formed were studied. As a result, it was observed that the thermal conductivity coefficients of the composites increased with the increase of the crystallinity ratio of the fiber. Moreover, the increased fiber concentration significantly increased the thermal conductivity coefficient of the composite materials produced.

Research on Rust Bilge Cracking of Reinforced Concrete Pier in Marine Environment

2011 ◽  
Vol 368-373 ◽  
pp. 1073-1077
Author(s):  
Xiao Feng Luo ◽  
Guo Hui Xing
Keyword(s):  
Heat Transfer ◽  
Thermal Expansion ◽  
Reinforced Concrete ◽  
Marine Environment ◽  
Coefficient Of Thermal Expansion ◽  
Expansion Method ◽  
Ion Concentration ◽  
Transient Heat Transfer ◽  
Chloride Diffusion ◽  
Time Step

Based on coupled thermal-mechanical method, rust bilge cracking of reinforced concrete pier in marine environment has been studied in this paper. Because of the similarity of differential equations of chloride diffusion and transient heat transfer, chloride diffusion is completed by using the transient heat transfer method. The chloride ion concentration at the reinforcement surface is obtained and is taken as temperature load at each time step. After introducing the equivalent time-varying coefficient of thermal expansion, the corrosion-induced reinforcement expansion and concrete cracking are simulated by the thermal expansion method. Numerical results show that the method is reasonable and feasible.

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