Effects Of Sintering Additive Microstructure And Proton Irradiation On Thermal Conductivity Of Spark Plasma Sintered Sic Ceramics
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Effects Of Sintering Additive Microstructure And Proton Irradiation On Thermal Conductivity Of Spark Plasma Sintered Sic Ceramics
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Author : Zhenfei Chai
language : en
Publisher:
Release Date : 2021
Effects Of Sintering Additive Microstructure And Proton Irradiation On Thermal Conductivity Of Spark Plasma Sintered Sic Ceramics written by Zhenfei Chai and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.
Sintering Techniques Of Materials
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Author : Arunachalam Lakshmanan
language : en
Publisher: BoD – Books on Demand
Release Date : 2015-04-01
Sintering Techniques Of Materials written by Arunachalam Lakshmanan and has been published by BoD – Books on Demand this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015-04-01 with Technology & Engineering categories.
The book covers new sintering techniques on ceramic materials, metals and composites as well as reprocessed PTFE. The book covers theoretical as well as experimental aspects on Spark Plasma Sintered (SPS) Porous copper, development of cutting blades with high hardness and resistance to cracking and wear, increased microhardness of austenitic steel ? TiB2 composites obtained with high pressure - high temperature sintering, Al2O3 porous body with cotton as the template and excellent thermal insulation with direct application for refractories as well as Metal matrix composites added nanostructured tantalum carbide and an overview of different sintering techniques used in powder metallurgy. Finally recycling of PTFE scrap materials using ram extrusion and compression molding is described.
Effect Of Sintering Time And Composition Of Sintering Aids On The Core Rim Microstructure And Material Properties Of Spark Plasma Sintered Silicon Carbide
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Author : Steven E. Bagienski
language : en
Publisher:
Release Date : 2013
Effect Of Sintering Time And Composition Of Sintering Aids On The Core Rim Microstructure And Material Properties Of Spark Plasma Sintered Silicon Carbide written by Steven E. Bagienski and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Ceramic materials categories.
Silicon carbide is an industrial ceramic used for many applications. Due to its complicated crystal structure, many different types exist and can be made to have a "core-rim" microstructure in individual grains. In this work, SiC samples were processed via a co-precipitation and spark plasma sintered to examine the core-rim microstructure by altering the sintering time when spark plasma sintered, the additive amounts, and the polytype composition. Samples were characterized via density, hardness, FESEM, XRD, and Raman analysis depending on the type of samples. The density and hardness of samples showed that the samples for the dwell time studied were densified but the ones of varying polytype were not. The hardness generally increased with longer sintering dwell times, whereas the density measurements were too similar to discern any appreciable difference between samples. The extent of the core-rim structure as seen from FESEM images had a large variability, but preliminary results hint at less core-rim features with longer dwell times. The XRD results were typical of the materials present in the sample and showed a SiO2 phase.
Effect Of Sintering Temperature On The Microstructure Of Liquid Phase Sintered Sic Ceramics
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Author : Maxwell R. DeGregory
language : en
Publisher:
Release Date : 2022
Effect Of Sintering Temperature On The Microstructure Of Liquid Phase Sintered Sic Ceramics written by Maxwell R. DeGregory and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022 with Ceramic engineering categories.
This thesis investigated the change in microstructure of liquid phase sintered (LPS) silicon carbide. The four samples were each comprised of 98 wt% cubic SiC, 1 wt% alumina (A12O3), and 1 wt% yttria (Y2O3). They were sintered using spark plasma sintering at temperatures of 1350, 1450, 1500, 1550 °C for 30 minutes. SEM images and x-ray characterization were performed to observe grain growth and phase transformations of the material.
Evaluating The Effect Of Powder Oxygen Content On The Microstructure And Mechanical Properties Of Silicon Carbide Densified By Spark Plasma Sintering
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Author : Vincent Alexander DeLucca
language : en
Publisher:
Release Date : 2017
Evaluating The Effect Of Powder Oxygen Content On The Microstructure And Mechanical Properties Of Silicon Carbide Densified By Spark Plasma Sintering written by Vincent Alexander DeLucca and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with Silicon carbide categories.
Silicon carbide (SiC) is an important material in industry due to its favorable mechanical, thermal, chemical, and electrical properties. While it has been mainly used as an abrasive material in the past, more modern applications like armor and other structural applications, often require densified ceramic bodies. SiC powders can be densified in a number of ways, but one common method is solid-state sintering, either with or without applied pressure. It is well known that in the presence of oxygen, pure SiC will form a passivating oxide layer of silica (SiO2) on its surface. This poses a problem in sintering as SiO2 can inhibit the densification of solid state sintered SiC. This thesis examines the effects of varying oxygen content levels in silicon carbide powders on the microstructure and mechanical properties of the resulting densified bodies after solid state sintering via the spark plasma sintering (SPS) method. Two commercial SiC powders were obtained, characterized, and treated to introduce a range of different oxygen content levels. These powders were then densified via the spark plasma sintering method using boron carbide and carbon additives to produce dense samples. Three series of samples were made using each powder, one varying the amount of carbon added as a particulate, one varying the amount of carbon added as a liquid resin, and one where the oxygen content of the powder was directly manipulated by HF washing, aging, or heat treating. The dense SiC samples were then characterized to determine the effect of the powder's oxygen content on the microstructure and mechanical properties. The samples were examined using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), Knoop microhardness testing, and nondestructive ultrasonic evaluation techniques including acoustic spectroscopy and conventional NDE methods. SEM and EBSD analysis revealed that changes in the powder oxygen content can result in a number of microstructural effects. At intermediate oxygen levels, exaggerated grain growth can occur resulting in large plate-like grains, accompanied by a transformation from the 6H to 4H SiC polytype. At higher oxygen levels, densification may be inhibited and at very high oxygen contents formation of an oxygen rich secondary phase can occur. Varying the oxygen content of the SiC powder also significantly affects the mechanical properties of the dense ceramic. Ultrasonic measurements of the elastic properties showed a clear decrease in the elastic moduli as the oxygen content is increased. Knoop microhardness measurements show similar behavior with a reduction in hardness with increased powder oxygen content.
Non Oxide Ceramic Composites Prepared By Sol Gel And Spark Plasma Sintering Processes
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Author : Manyuan Zhou
language : en
Publisher:
Release Date : 2014
Non Oxide Ceramic Composites Prepared By Sol Gel And Spark Plasma Sintering Processes written by Manyuan Zhou and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
Ultra High Temperature Ceramics (UHTCs) are the most promising candidates for high temperature applications in extreme environments, such as conditions experienced during re-entry of out space flying objects, for their known high melting points, good chemical and thermal stability and high thermal conductivity. To improve the densification and oxidation resistance of UHTCs, a second phase, such as silicon carbide, is usually added to monolithic UHTCs to form ceramic matrix composites. While UHTCs/composites have many unique advantages for high temperature applications, they are very difficult to densify due to their very strong covalent chemical bonds and very high melting point. Conventional methods for processing UHTCs usually use powders as starting materials. A major issue of the conventional methods is the poor mixing/processing of powders with different densities and sizes, especially for nano-sized powders. Thus more research needs to be focused on improving UHTCs' densification, microstructure and properties.This thesis studies the development of novel sol-gel techniques for preparation of starting materials and spark plasma sintering (SPS) for densification of UHTCs and composites. The thesis is organized into eight chapters. The First Chapter is an introduction to the thesis structure organization. The Second Chapter is the background of the research and literature review. Chapter Three is a description of the experimental procedures and characterization techniques. In the first result chapter, Chapter Four, silicon nitride ceramic and silicon nitride/titanium nitride composite were fabricated by hot pressing and spark plasma sintering (SPS) respectively to study the effect of the SPS DC current on the densification, microstructure and properties of conductive and non-conductive materials. A sol-gel based approach was investigated to improve the UHTC ceramics/composites with fine microstructures in Chapter Five. Although sol-gel techniques may not be suitable for making large bulk materials, they have unique advantages on modifying or improving the microstructures, properties and surfaces of materials through the solution chemistry approach. The sol-gel processing technique was used to synthesize TiC/SiC nanocomposites and followed by SPS sintering. Dense TiC/SiC composites were fabricated successfully to form a microstructure consisted of nano TiC and SiC grains. Work in Chapter Six used a sol-gel infiltration technique to fabricate dense TiC/SiC nanocomposites from porous TiC scaffolds. In Chapter Seven, zirconium diboride/silicon carbide composites of fine microstructures were successfully fabricated by sol-gel coating of ZrB2 powders and SPS sintering. Compared to conventional ceramic processing methods, the sol-gel based wet chemistry process has many unique advantages such as homogeneous mixing of starting materials, infiltration of porous green bodies with complex shapes, avoiding the formation of intermediate transit phase/liquid phase in sintering, restricting grain growth and assisting densification by reaction. Chapter Eight presents the conclusions of the thesis and provides some directions for future work.
Sintering Technology
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Author : Malin Liu
language : en
Publisher: BoD – Books on Demand
Release Date : 2018-10-31
Sintering Technology written by Malin Liu and has been published by BoD – Books on Demand this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-10-31 with Technology & Engineering categories.
Sintering technology is an old and extensive technology in many areas, and it has been used especially in ceramic fabrication. This book covers many fields, for example, the development of different sintering technologies in recent years, such as spark plasma sintering, flash sintering, microwave sintering, reaction and laser sintering, and so on, and also some special ceramic material fabrication methods and applications, such as carbon nanotubes mixed with alumina and zirconia ceramics, pure and doped zirconia, ZnO ceramic varistors, and so on.
Spark Plasma Sintering Of Materials
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Author : Pasquale Cavaliere
language : en
Publisher: Springer
Release Date : 2019-02-18
Spark Plasma Sintering Of Materials written by Pasquale Cavaliere and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-02-18 with Technology & Engineering categories.
This book describes spark plasma sintering (SPS) in depth. It addresses fundamentals and material-specific considerations, techniques, and applications across a broad spectrum of materials. The book highlights methods used to consolidate metallic or ceramic particles in very short times. It highlights the production of complex alloys and metal matrix composites with enhanced mechanical and wear properties. Emphasis is placed on the speed of the sintering processes, uniformity in product microstructure and properties, reduced grain growth, the compaction and sintering of materials in one processing step, various materials processing, and high energy efficiency. Current and potential applications in space science and aeronautics, automation, mechanical engineering, and biomedicine are addressed throughout the book.
Silicon Carbide Ceramics
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Author : S. Somiya
language : en
Publisher: Springer Science & Business Media
Release Date : 1991-08-31
Silicon Carbide Ceramics written by S. Somiya and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 1991-08-31 with Technology & Engineering categories.
Silicon carbides have major industrial uses as high temperature structural ceramic materials. These two volumes are translated from the Japanese and provide a comprehensive account of the seminal work going on in Japan.
Field Assisted Sintering Of Refractory Carbide Ceramics And Fiber Reinforced Ceramic Matrix Composites
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Author : Sean Gephart
language : en
Publisher:
Release Date : 2014
Field Assisted Sintering Of Refractory Carbide Ceramics And Fiber Reinforced Ceramic Matrix Composites written by Sean Gephart and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
The sintering behaviors of silicon carbide (SiC) and boron carbide (B4C) based materials were investigated using an emerging sintering technology known as field assisted sintering technology (FAST), also known as spark plasma sintering (SPS) and pulse electric current sintering (PECS). Sintering by FAST utilizes high density electric current, uniaxial pressure, and relatively high heating rate compared to conventional sintering techniques.This effort investigated issues of scaling from laboratory FAST system (25 ton capacity) to industrial FAST system (250 ton capacity), as well as exploring the difference in sintering behavior of single phase B4C and SiC using FAST and conventional sintering techniques including hot-pressing (HP) and pressure-less sintering (PL). Materials were analyzed for mechanical and bulk properties, including characterization of density, hardness, fracture toughness, fracture (bend) strength, elastic modulus and microstructure. A parallel investigation was conducted in the development of ceramic matrix composites (CMC) using SiC powder impregnation of fiber compacts followed by FAST sintering.The FAST technique was used to sinter several B4C and SiC materials to near theoretical density. Preliminary efforts established optimized sintering temperatures using the smaller 25 ton laboratory unit, targeting a sample size of 40 mm diameter and 8 mm thickness. Then the same B4C and SiC materials were sintered by the larger 250 ton industrial FAST system, a HP system, and PL sintering system with a targeted dense material geometry of 4x4x0.315 inches3 (101.6x101.6x8 mm3). The resulting samples were studied to determine if the sintering dynamics and/or the resulting material properties were influenced by the sintering technique employed. This study determined that FAST sintered ceramic materials resulted in consistently higher averaged values for mechanical properties as well as smaller grain size when compared to conventionally sintered materials. While FAST sintered materials showed higher average values, in general they also showed consistently larger variation in the scattered data and consequently larger standard deviation for the resulting material properties. In addition, dynamic impact testing (V50 test) was conducted on the resulting materials and it was determined that there was no discernable correlation between observed mechanical properties of the ceramic materials and the resulting dynamic testing.Another study was conducted on the sintering of SiC and carbon fiber reinforced SiC ceramic matrix composites (CMC) using FAST. There has been much interest recently in fabricating high strength, low porosity SiC CMC's for high temperature structural applications, but the current methods of production, namely chemical vapor infiltration (CVI), melt infiltration (MI), and polymer infiltration and pyrolysis (PIP), are considered time consuming and involve material related shortcomings associated with their respective methodologies. In this study, SiC CMC's were produced using the 25 ton laboratory unit with a target sample size of 40 mm diameter and 3 mm thickness, as well as on the larger 250 ton industrial FAST system targeting a sample size of 101.6x101.6x3 mm3 to investigate issues associated with scaling. Several sintering conditions were explored including: pressure of 35-65 MPa, temperature of 1700-1900°C, and heating rates between 50-400°C/min. The SiC fibers used in this study were coated using chemical vapor deposition (CVD) with boron nitride (BN) and pyrolytic carbon to act as a barrier layer and preserve the integrity of the fibers during sintering. Then the barrier coating was coated by an outer layer of SiC to enhance the bonding between the fibers and the SiC matrix. Microstructures of the sintered samples were examined by FE-SEM. Mechanical properties including flexural strength-deflection and stress-strain were characterized using 4-point bend testing. Tensile testing was performed on the larger 101.6x101.6x3 mm samples. The microstructures of samples sintered using the 25 ton laboratory FAST system showed a reduction in porosity and good adhesion between the fiber-fiber and fiber-matrix interface. The microstructures of samples sintered on the 250 ton industrial FAST system showed a reduction in porosity, but there was visible reaction of the fiber and fiber coatings with the surrounding matrix. Additionally, there was significant radial cracking of the fibers visible in the microstructures.There is gap in the understanding of sintering behavior between laboratory and industrial scale FAST systems. The vast majority of publications on FAST sintering have been primarily focused on small sample geometries (20 mm diameter, less than 3 mm thick). A study was coordinated to investigate the thermal properties during heating and cooling using a 250 ton industrial FAST system at 900°C using B4C and SiC materials inside the graphite die assembly. The thermal properties were then compared to the resulting material properties of the identically sintered B4C and SiC to approximately 94% relative density, at a temperature of 1950°C, pressure of 45 MPa, 10 minute hold, and heated at a rate of 100°C/min. The study determined that at 900°C there were significant thermal gradients within the system for the examined materials, and that these gradients correlated well with the material property difference of the samples sintered at higher temperatures where the gradients are presumably larger due to an increase in radiative heat loss. The observed temperatures throughout the graphite were significantly different between B4C and SiC. These temperatures also correlated well with the material properties of the sintered products which showed more substantial variation for B4C when compared to SiC which was overall less affected by thermal gradients. This was attributed to the intrinsic thermal conductivity difference between the two subject materials which was manifested as thermal gradients throughout the material and graphite die assembly. Additionally, both the observed temperature gradients throughout the graphite die assembly and the difference in temperature reading between the optical pyrometer and thermocouples were significantly larger for the 250 ton FAST system than previous publications have demonstrated experimentally or via modeling of smaller laboratory scale systems. The findings from this work showed that relative to conventional sintering methods, the FAST process demonstrated comparable or improved material and mechanical properties with a significantly shorter processing cycle. However, the results demonstrated on the 25 ton laboratory scale unit were significantly different compared to results for the same materials sintered using the 250 ton industrial scale unit. The temperature gradients observed on the 250 ton FAST unit were significantly larger than previous reports on smaller FAST units. This result showed future efforts to scale up the FAST sintering process while maintaining similar results will require careful attention to minimizing temperature gradients. This could potentially be achieved by reducing radiative heat loss during processing and/or optimizing the graphite die design and implementing heat spreaders in specific locations dependent on the host material's thermal and electrical properties as well as the sample geometry.