Showing papers on "Ceramic matrix composite published in 2011"

Advanced Materials for Thermal Management of Electronic Packaging

Abstract: CH. 1. Thermal managing fundamentals and design guide in electronic packaging.- 1.1 Introduction.- 1.2 Thermal management challenges and common.- concerns.- 1.3 Fundamentals of heat transfer.- 1.4 Thermal management solutions.- 1.5 Design for advanced thermal management of electronic packaging.- 1.6 Materials selection for advanced thermal management.- 1.7 Environmental compliance of thermal managing materials.- CH. 2. Characterization methodology of thermal managing materials.- 2.1 Thermal properties and measurement techniques.- 2.2 Electrical properties and measurement techniques.- 2.3 Thermomechanical characterization.- 2.4 Analytical techniques for materials characterization.- 2.5 Surface finish and contact interface compatibility.- 2.6 Reliability analysis and environmental performance evaluation.- CH. 3. Electronic packaging materials and their thermal managements.- 3.1 Materials selection for electronic packaging.- 3.2 Ceramics and semiconductors.- 3.3 Electronic glasses.- 3.4 Polymers.- 3.5 Monolithic metals.- 3.6 Metallic composites.- 3.7 Multimaterial laminates.- 3.8 Printed Circuit Board (PCB) Materials.- 3.9 Thermal interface materials.- 3.10 Advanced thermally conductive materials.- CH. 4. THERMALLY conductive carbonaceous materials and carbon matrix composites.- 4.1 Introduction.- 4.2 Natural and industrial graphite.- 4.3 Pyrolytic graphite.- 4.4 Graphite/Carbon Foams.- 4.5 Thermally conductive carbon fibers.- 4.6 Diamond.- 4.7 Carbon Nanotubes.- 4.8 Carbon/carbon composites.- CH. 5. Thermally conductive polymer matrix composites.- 5.1 Introduction.- 5.2 Polymer matrix types.- 5.3 Reinforcements selection and its effect on thermal conductivity.- 5.4 General fabrication and manufacturing processes.- 5.5 Types and applications for thermal management.- CH. 6. High thermal conductivity metal matrix composites.- 6.1 Introduction.- 6.2 Processing of metal matrix composites.- 6.3 Aluminum matrix composites.- 6.4 Copper matrix composites.- 6.5 Other metal matrix composites.- CH. 7. Thermally conductive ceramic matrix composites.- 7.1 Introduction.- 7.2 Diamond-SiC composites.- 7.3 Carbon-SiC Composites.- 7.4 Reaction-Bonded SiC.- 7.5 Aluminum-toughened SiC.- 7.6 CNT/Ceramic- carbon nanotube composites.- CH. 8. Thermal interface materials in electronic packaging.- 8.1 Thermal contact conductance and requirement for thermal interface materials.- 8.2 Metallic thermal interface materials.- 8.3 Thermal grease.- 8.4 Thermally conductive elastomer materials.- 8.5 Phase change materials.- 8.6 Polymer solder hybrid materials.- 8.7 Fiber-reinforced thermal interface materials.- 8.8 Graphite based thermal interface material.- 8.9 Nanotechnology based thermal interface materials.- 8.10 Thermal interface materials selection.- CH. 9. Materials and design of advanced heat spreader and air cooling heat sink.- 9.1 Introduction.- 9.2 Spreading and constriction resistance.- 9.3 Type of heat spreaders and their materials selection.- 9.4 Air cooling heat sink.- 9.4.1 Heat sink design constraints and design parameters.- 9.5 Nanostructure heat sink and complex spreader sink.- CH. 10. Liquid cooling devices and materials selection.- 10.1 Introduction.- 10.2 Indirect single-phase liquid cooling.- 10.3 Direct immersion cooling.- 10.4 Spray cooling and jet impingement.- 10.5 Heat pipe cooling.- 10.6 Refrigeration cooling.- 10.7 High-flux cooling with phase-change heat transfer.- CH. 11. Thermoelectric cooling through thermoelectric materials.- 11.1 Introduction.- 11.2 Thermoelectric effects.- 11.3 Design and architecture of thermoelectric cooling devices.- 11.4 Thermoelectric materials and future development trends.- CH. 12. Development and applications of advanced thermal managing materials.- 12.1 Materials development routine and methodology.- 12.2 Smart composites and multifunctional materials for thermal management.- 12.3 Thermal managing materials with enhanced EMI shielding and absorbing performance.- 12.4 Applications.- 12.5 Future trends.-

A Tough Silicon Nitride Ceramic with High Thermal Conductivity

Abstract: IO N The world is shifting energy sources from fossil fuel to electric power in order to cope with the energy and environmental problems. Driven by the demand for effi cient control and conversion of electric power, power electronic device technology is advancing toward higher voltage, larger current, greater power density, and smaller size, and this trend is poised to be accelerated with the replacement of Si by the wide-bandgap semiconductors (SiC and GaN) in the near future. [ 1 , 2 ] However, the high power will induce large thermal stresses in the devices, which pose great challenges for the assembly of the devices and the packaging materials, in particular the brittle ceramic substrates that provide functions of electrical insulation and heat dissipation. In many occasions, even the two high-grade ceramic substrate materials, AlN and Si 3 N 4 , become cracked due to low mechanical strength and fracture toughness (for AlN) or insuffi cient thermal conductivity (for Si 3 N 4 ). [ 3 , 4 ] The reliability problem caused by the ceramic substrates has become a bottleneck hindering the advancement of power device technology. Search for new ceramic materials with better thermomechanical properties is an urgent issue. Here, we show a new Si 3 N 4 ceramic that possesses a very high thermal conductivity (177 W m − 1 K − 1 ) along with a high fracture toughness (11.2 MPa m 1/2 ) and a high fracture strength (460 MPa). We expect this Si 3 N 4 will be used as the next-generation insulating substrate material for high-power electronic devices. Silicon nitride mainly exists in two hexagonal polymorphs, namely α and β -Si 3 N 4 , which are generally regarded as lowand high-temperature crystal forms, respectively. [ 5 , 6 ] As a highly covalent compound, Si 3 N 4 transports heat primarily by phonons at room temperature and below. In 1995, Haggerty and Lightfoot predicted that the intrinsic thermal conductivity of Si 3 N 4 might be 200 to 320 W m − 1 K − 1 at room temperature. [ 7 ] Later, Hirosaki et al. estimated that the intrinsic thermal conductivities of a β -Si 3 N 4 crystal were 170 and 450 W m − 1 K − 1 along the a -axis and c -axis, respectively. [ 8 ] However, the thermal conductivity of Si 3 N 4 ceramics is much lower than the intrinsic values. Si 3 N 4 ceramics are polycrystalline materials consolidated by liquid-phase sintering. During sintering, Si 3 N 4 raw powder, which is usually α phase, converts to the more stable β phase. In the microstructure of Si 3 N 4 ceramics,

Materials for High Temperature Engineering Applications

Abstract: 1 Introduction.- 1.1 Need for High Temperature Materials.- 1.2 High Temperature Materials.- 1.3 Historical Development of High Temperature Materials ....- 2 Design and Manufacture.- 2.1 Plant Design and Material Selection.- 2.2 Component Manufacture.- 2.3 Process Models.- 2.4 Component Life Extension.- 3 Requirements of High Temperature Materials.- 3.1 Environmental Resistance.- 3.1.1 Oxidation.- 3.1.2 Sulphidation.- 3.1.3 Salt- and Ash-Deposit Corrosion.- 3.1.4 Carburisation.- 3.2 Erosion.- 3.3 Wear.- 3.4 Mechanical Behaviour.- 3.4.1 Zero Time Deformation.- 3.4.2 Creep.- 3.4.3 Mechanical Fatigue.- 3.4.4 Thermo-Mechanical Fatigue.- 3.4.5 Corrosion-Fatigue.- 3.5 Physical Properties.- 4 Increasing Temperature Capability.- 4.1 Metallic Materials.- 4.1.1 Solid Solution Strengthening.- 4.1.2 Precipitation Strengthening.- 4.1.3 Dispersion Strengthening.- 4.1.4 Grain Size and Grain Boundary Effects.- 4.1.5 Environmental Resistance.- 4.2 Ceramic Materials.- 4.2.1 Phase Control.- 4.2.2 Defect Tolerance.- 4.2.3 Thermal Shock Resistance.- 4.3 Composite Materials.- 5 Steels.- 5.1 Ferritic Heat Resistant Materials.- 5.2 Creep Resisting Martensitic Steels.- 5.3 Austenitic Steels.- 5.3.1 Corrosion Resistant Austenitic Steels.- 5.3.2 High Strength Austenitic Steels.- 5.4 Controlled Transformation Stainless Steels.- 6 Cast Iron.- 6.1 Grey Cast Irons.- 6.2 Spheroidal Graphite Irons.- 6.3 Austenitic Irons.- 7 Nickel Alloys.- 7.1 Oxidation and Corrosion Resistant Nickel Alloys.- 7.2 Nickel Superalloys.- 7.2.1 Alloy Composition-Dominated Developments.- 7.2.2 Developments Dependent on Process and Alloy Composition.- 7.2.3 Process Dominated Developments.- 8 Cobalt Alloys.- 9 Refractory Metals.- 10 Titanium.- 10.1 Production.- 10.2 Alloys.- 10.3 Component Manufacture.- 11 Intermetallic Materials.- 11.1 Titanium Aluminides.- 11.2 Nickel Aluminides.- 11.3 Iron Aluminides.- 11.4 Speculative Intermetallics.- 12 Cermets.- 12.1 Cemented Carbide Cutting Tools.- 12.2 Wear Resistant Coatings.- 13 Refractories and Insulating Materials.- 14 Engineering Ceramics.- 14.1 Manufacture.- 14.2 Properties.- 14.3 Alumina.- 14.4 Zirconia.- 14.5 Silicon Carbide.- 14.6 Silicon Nitride.- 14.7 Glass Ceramics.- 15 High Temperature Composite Materials.- 15.1 Metal Matrix Composites.- 15.2 Titanium Matrix Composites.- 15.3 Carbon and Carbon-Carbon Composites.- 15.4 Ceramic Matrix Composites.- 15.5 Intermetallic Matrix Composites.- 16 Coatings for High Temperature Materials.- 16.1 Corrosion/Oxidation Resistant Coatings.- 16.2 Thermal Barrier coats.- References.

Development of a Macroscopic Damage Model for Woven Ceramic Matrix Composites

Abstract: The aim of this article is to propose a macroscopic damage model, which describes the nonlinear behavior observed on woven composites with ceramic matrix. The model is built within a thermodynamic ...

Chemically bonded phosphate ceramics composites reinforced with graphite nanoplatelets

Abstract: Chemically bonded phosphate ceramic (CBPCs) composites with 1.0 wt.% graphite nanoplatelets (GNPs) reinforcement have been manufactured. The GNPs were functionalized by different procedures, a nitric acid oxidation and a dried oxidation in open air. Two different mixing techniques were used, Thinky and Resonant Acoustic Mixing (RAM). Results showed both techniques are effective to remove most of the air bubbles and a homogeneous distribution of phases was observed with different microscopy techniques. The microstructure was identified by using optical and scanning electron microscopes, X-ray microtomography, and X-ray diffraction (XRD). The bending strength was increased from less than 10 MPa (literature) to more than 23 MPa. The thermo gravimetric analysis (TGA) technique was used to analyze the thermal stability at high temperature. The main goal in this paper is to enhance the bending strength of the CBPCs reinforced with GNPs, as a substitute composite material for ceramics and cements in structural applications.

Electrical Resistance as a Nondestructive Evaluation Technique for SiC/SiC Ceramic Matrix Composites Under Creep‐Rupture Loading

Abstract: SiC/SiC ceramic matrix composites under creep-rupture loading accumulate damage by means of local matrix cracks that typically form near a stress concentration, such as a 90° fiber tow or a large matrix pore, and grow over time. Such damage is difficult to detect through conventional techniques. This study demonstrates that electrical resistance is a viable method of monitoring and inspecting damage in SiC/SiC composites at high temperature. Both interrupted and uninterrupted creep-rupture experiments were performed at 1315°C and 110 MPa with in situ resistance measurements. A linear relationship was found between resistance and cumulative crack depth.

Ceramic matrix composites in the alumina/5–30vol.% YAG system

Abstract: The preparation technique of the particulate composite materials in the alumina/YAG system was elaborated. Within alumina particles suspension yttria precursor was precipitated with ammonium carbonate. Drying and calcination at 600 °C resulted in the mixture of alumina and yttria particles, the latter being much finer than alumina particles. This mixture was additionally homogenized by short attrition milling in an aqueous suspension. Sintering of such powders results in the materials composed of YAG inclusions of sizes smaller than shown by alumina grains and evenly distributed within the matrix. YAG particles result from the reaction of Y 2 O 3 with Al 2 O 3 during heat treatment. YAG inclusions limit effectively grain growth of the alumina matrix. Hardness, fracture toughness, strength, Young modulus and wear susceptibility of composites and pure alumina were measured. Composites show higher hardness and in some cases higher fracture toughness and wear resistance than pure alumina polycrystals.

Hybrid rotor disk assembly with ceramic matrix composites platform for a gas turbine engine

Abstract: A Ceramic Matrix Composite (CMC) platform for an airfoil of a gas turbine engine includes a CMC platform segment which at least partially defines an airfoil profile.

Rare‐Earth Disilicates As Oxidation‐Resistant Fiber Coatings for Silicon Carbide Ceramic–Matrix Composites

Abstract: Current SiC-based ceramic–matrix composites (SiC–SiC CMCs) rely on carbon or boron nitride fiber–matrix interphases for toughness and flaw tolerance. However, oxidation of these interphases can be performance limiting in many CMC applications. The γ-polymorph of the rare-earth disilicates (RE2Si2O7) is a potential oxidation-resistant alternative to carbon or BN. The formation of γ-Y2Si2O7 and γ-Ho2Si2O7 at different temperatures and processing environments was investigated. Silica–yttrium hydroxide and silica–holmium hydroxide dispersions were made and heat treated at 1200°–1400°C for 8 h in air and argon. LiNO3 was added to the dispersions to enhance the formation of γ-Y2Si2O7 and γ-Ho2Si2O7. The effects of excess silica and LiNO3 dopant on the formation of γ-Y2Si2O7 were investigated. Coatings of Y2Si2O7 and Ho2Si2O7 were made on α-SiC plate and SCS–0 SiC fiber using these dispersions. These were heat treated in argon and argon—500 ppm oxygen mixtures at 1400°C/8 h. For coatings heat treated in argon—500 ppm oxygen mixtures, X-ray diffraction showed the formation of single phase γ-Ho2Si2O7 and a mixture of γ and β-Y2Si2O7 at 1400°C. Scanning electron microscopic image analysis gave an estimate of 18 vol% of excess silica for γ-Y2Si2O7 formed with high Si:Y ratio and ∼5 vol% excess silica for material formed with lower Si:Y ratio. Transmission electron microscopy of samples directly beneath indentations showed both extensive dislocation slip and fracture.

An integrated assembly method of sandwich structured ceramic matrix composites

Abstract: Sandwich structured composites have been widely studied and applied at ambient temperature in aeronautical, automobile and naval applications. For high temperature applications, an integrated ceramic sandwich structure could take advantage of multiple functions such as skin stiffness and core insulation. For thermo-structural applications, skins must be made of ceramic matrix composites (CMC) because of their strength, their resistance to high temperatures (beyond 1000 °C), and their low densities. Concerning foam cores, some carbides (e.g. SiC) are, for their outstanding thermo-mechanical properties, the most appropriate. These foams can withstand long oxidative exposing conditions with low material degradation. This paper presents an assembly method of SiC based sandwich structured CMC. It is performed during sandwich manufacturing in an integrated fashion and allows the production of complex shapes at low costs. Produced flat sandwich panels, characterized by three point bending tests, showed a marked toughening behaviour.

Types of Composites

Abstract: Publisher Summary Composites are materials made up of two or more materials that are combined in a way that allows the materials to stay distinct and identifiable. The purpose of composites is to allow the new materials to have strengths from both materials, often times covering the original materials weaknesses. Composites are usually classified by the type of reinforcements they use. These reinforcements are embedded into a matrix that holds it together. The reinforcements are used to strengthen the composites. This chapter discusses four types of composites—namely, polymer matrix composites, carbon matrix composites, metal matrix composites, and ceramic matrix composites. Polymer matrix composites are plastics (resins) within which there are embedded fibers. The plastic is known as the matrix, and the fibers orientated within it are known as the reinforcement. The reinforcement tends to be stiffer and stronger than the matrix providing stiffness and strength. The primary reason why polymer matrix composites are chosen for the manufacture of components is because of the weight saving relative to their stiffness and strength.

Mechanical properties and oxidation resistance of α-alumina/multi-walled carbon nanotube composite ceramics

Abstract: In this study, α-alumina/multi-walled carbon nanotube (α-Al2O3/MWCNT) composite ceramics with 5 wt.% CNTs additions were synthesized using ball-milled and hydrothermal crystallization methods, respectively, followed by hot-pressing. The mechanical properties and oxidation resistance of the two types of composite ceramics were measured using micromechanical testing system, thermogravimetry, and differential scanning calorimetry. Compared with monolithic Al2O3 ceramic, the fracture toughness and flexural strength of the composite ceramics synthesized using ball-milled method were improved by 61.1% and 17.2%, respectively due to the distinct “pinning” effect of MWCNTs, and the other type of composite ceramics’ were improved by 80.3% and 24.6% due to the obvious pull-out effect of the ceramic-coated MWCNTs and the smaller grain size. At the same time, the weight losses of the ceramic samples exposed to air at 1000 °C for 1 h were inconspicuous. It indicates the composite ceramics have excellent oxidation resistance.

Influence of fiber failure on fatigue hysteresis loops of ceramic matrix composites

Abstract: An analytical methodology has been developed to investigate the influence of fiber failure on fatigue hysteresis loops of ceramic matrix composites in this article. During fatigue loading, matrix c...