Download or read book Thermal Processing and the Evolution of Composition Structure and Properties for Sol gel Derived PZT Thin Layers written by Charles David Edward Lakeman and published by . This book was released on 1994 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thermal Processing and the Evolution of Composition Structure and Properties for Sol gel Derived Lead Zirconate Titanate Thin Layers written by Charles David Edward Lakeman and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Research is reported for the relationships that exist between processing, composition and structure development, and properties, for sol-gel derived $rm Pb(Zrsb{0.53}Tisb{0.47})Osb3$ (PZT) thin layers. Emphasis was placed on the effect of thermal processing conditions on the gel-to-ceramic conversion. In addition, the effects of interfacial reactions, and residual stresses on the measured properties were also considered. The purpose of the work was to contribute to the fundamental understanding of processes which occur during the high temperature treatment of sol-gel derived thin layers. The gel-to-ceramic conversion was monitored by transmission electron microscopy, diffuse reflectance infrared spectroscopy, and X-ray diffraction. As-deposited coatings were found to be amorphous with compositional heterogeneity at the nanoscale. This is the first report which identifies the nature of the compositional heterogeneity. Structural rearrangement occurred during thermal processing and, for slow heating (50$spcirc$C/min), the coatings approached compositional uniformity on crystallization into the perovskite phase. However, for faster heating rates, the degree of structural rearrangement was limited, thereby decreasing the shrinkage normal to the coating, and crystallization was shifted to a higher temperature. Also, for very rapid thermal processing (5000$spcirc$C/min), compositional heterogeneity was retained in the coatings after crystallization. An apparent dependence on thickness for the properties for ferroelectric PZT thin layers was observed. It was confirmed that a cover coat of a PbO-precursor deposited onto the gel-derived layers prior to firing compensated for the volatilization of PbO which occurred during heating, resulting in coatings which displayed improved properties over those prepared without a cover coat. A simple series capacitor model was investigated to interpret the data. SIMS and TEM analyses indicated that diffusion of some of the species resulted in the formation of a sub-electrode nano-crystalline phase, however, no second phases were observed between the electrode and the coating. Measurements of the residual stress state in PZT coatings deposited onto platinized silicon substrates, and fired at 700$spcirc$C, indicated a tensile stress of approximately +200MPa in the plans of the coating. Thermal expansion mismatch stresses were calculated to be of the order of $-$300MPa in compression, indicating that large tensile stresses were generated during constrained shrinkage.

Download or read book Evolution of Local Structure and Stress Development During Thermal Treatment of Sol gel Derived PZT based Thin Layers written by Samit Sushil Sengupta and published by . This book was released on 1996 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Significant progress has been made in recent years on the deposition of ferroelectric thin layers by sol-gel processing. However, to sustain further improvements in the technique necessary for widespread applications, a systematic approach to the study of physical, chemical and structural changes that occur during transformation from the as-deposited state to the desired perovskite phase must be undertaken. In view of the need for a fundamental understanding of structure-processing relationships in these systems, this thesis investigates variations in local structure and network development for sol-gel derived precursors in the lead zirconate titanate (PZT) system as a function of heat treatment conditions. Structural studies were based on extended x-ray absorption fine structure (EXAFS) analysis of gels and thin layers. Consolidation of the thin layer network was monitored by in situ ellipsometry and thermal analysis techniques. The resulting constrained shrinkage for the deposited layers produced large stresses (up to 180 MPa), which were determined by wafer bending measurements. EXAFS measurements for partially heat-treated PZT gels are reported. After gels were dried and pyrolyzed, the amorphous structure was determined from results obtained from the titanium and zirconium K-edges and the lead L$rmsb{III}$-edge. For lead titanate (PT) and PZT53/47 gels, the results indicated the formation of separate TiO$sb6$ and ZrO$sb6$ units linked via corner-sharing oxygen atoms, with Pb in random positions. For lead zirconate (PZ) gels, both Zr-O-Pb and Zr-O-Zr linkages were possible. These findings indicate heterogeneity at the molecular level and nanoscale. Partially heat-treated thin layers of lead titanate deposited on polycrystalline alumina substrates were heat treated under various conditions to examine the evolution of the crystalline phase. Structural ordering was initiated by a progressive enhancement in the Pb-O coordination number and increased occupancy of Pb in the second shell of Ti, with a corresponding breakdown in the Ti-Ti second neighbor ordering. However, crystallization preceded complete development of the short-range order characteristic of the tetragonal perovskite unit. Densification of PZT thin layers spin-coated on silicon was monitored by shrinkage and optical measurements. With increasing Zr content, the net consolidation was greater and occurred over a wider temperature range. These differences were related to differences in the structure of the as-hydrolyzed precursors. Most of the total shrinkage (e.g., 40-45% linear shrinkage) on heating to 500$spcirc$C occurred during drying and pyrolysis, which resulted in large tensile stress ($sim$150MPa). Subsequent stress behavior was primarily governed by the thermal expansion mismatch between the substrate and the coating. Stress development for multideposited PT coatings was determined by the structure of the layer on which the coating was being deposited and heat treated. Progressive crystallization of the layer induced a change in the thermal expansion coefficient, thereby initiating a change in the stress state from tensile to compressive. The observed behavior is discussed in terms of nucleation mechanisms at the multilayer interfaces and within the coating as a whole. This study has demonstrated the importance of identifying structural pathways and developing a basic understanding of the densification behavior in sol-gel derived materials as a function of thermal processing conditions. The findings of this research work should aid in developing suitable experimental procedures for future processing of gel-derived thin layers.

Download or read book Sol Gel Technologies for Glass Producers and Users written by Michel Andre Aegerter and published by Springer Science & Business Media. This book was released on 2013-03-19 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sol-Gel Techniques for Glass Producers and Users provides technological information, descriptions and characterizations of prototypes, or products already on the market, and illustrates advantages and disadvantages of the sol-gel process in comparison to other methods. The first chapter entitled "Wet Chemical Technology" gives a summary of the basic principles of the sol-gel chemistry. The most promising applications are related to coatings. Chapter 2 describes the various "Wet Chemical Coating Technologies" from glass cleaning to many deposition and post-coating treatment techniques. These include patterning of coatings through direct or indirect techniques which have became very important and for which the sol-gel processing is particularly well adapted. Chapter 3 entitled "Bulk Glass Technologies" reports on the preparation of special glasses for different applications. Chapter 4 entitled "Coatings and Materials Properties" describes the properties of the different coatings and the sol-gel materials, fibers and powders. The chapter also includes a section dedicated to the characterization techniques especially applied to sol-gel coatings and products.

Download or read book Chemical Solution Deposition of Functional Oxide Thin Films written by Theodor Schneller and published by Springer Science & Business Media. This book was released on 2014-01-24 with total page 801 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first text to cover all aspects of solution processed functional oxide thin-films. Chemical Solution Deposition (CSD) comprises all solution based thin- film deposition techniques, which involve chemical reactions of precursors during the formation of the oxide films, i. e. sol-gel type routes, metallo-organic decomposition routes, hybrid routes, etc. While the development of sol-gel type processes for optical coatings on glass by silicon dioxide and titanium dioxide dates from the mid-20th century, the first CSD derived electronic oxide thin films, such as lead zirconate titanate, were prepared in the 1980’s. Since then CSD has emerged as a highly flexible and cost-effective technique for the fabrication of a very wide variety of functional oxide thin films. Application areas include, for example, integrated dielectric capacitors, ferroelectric random access memories, pyroelectric infrared detectors, piezoelectric micro-electromechanical systems, antireflective coatings, optical filters, conducting-, transparent conducting-, and superconducting layers, luminescent coatings, gas sensors, thin film solid-oxide fuel cells, and photoelectrocatalytic solar cells. In the appendix detailed “cooking recipes” for selected material systems are offered.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 886 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sol Gel Processing and Applications written by Y.A. Attia and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: During my professional career, I developed a strong interest in sol-gel technology, and worked on both xerogel and aerogel systems. My fascination with aerogels has driven me to explore their commercial potential, which is currently an important component of my company's business plan. Together with my co-workers, I have also worked on the preparation of controlled PZT and silica xerogels as well as thin film coatings of metals by the sol-gel technology, These experiences convinced me of the tremendous potentials of this technology. A conviction that is shared by many scientists, engineers, and business leaders around the globe. Many sol-gel derived products are already articles of commerce. However, to expand the commercial potential of sol-gel technology, two challenges must be met: (1) the quality of sol-gel derived products must continue to meet or exceed the quality of competing products, (2) the production cost of sol-gel products (specially aerogels) must continued to decline. A key to lowering the costs of sol-gel products is finding inexpensive precursors.

Download or read book Sol Gel Processing for Conventional and Alternative Energy written by Mario Aparicio and published by Springer Science & Business Media. This book was released on 2012-02-04 with total page 399 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sol-Gel Processing for Conventional and Alternative Energy is a comprehensive source of information on the use of sol-gel processing in materials in energy systems, conversion, storage, and generation. The volume editors include numerous applications, primarily in nuclear fuel processing, electrolytes for fuel cells, and dye-sensitized solar cells (DSSC). In addition to examining contemporary processing, properties, and industrial applications, "Sol-Gel Processing for Conventional and Alternative Energy" identifies materials challenges presented by conventional and alternative energy generation that require new materials and innovative processing. Each chapter is written by an internationally respected researcher. The book provides a state-of-the-art treatment of different aspects of materials for energy production, with a focus on processing, and covers related topics such as carbon sequestration, clean energy, and biofuels.

Download or read book The Summary of Engineering Research written by University of Illinois (Urbana-Champaign campus). Engineering Experiment Station and published by . This book was released on 1995 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Sol Gel Handbook written by David Levy and published by John Wiley & Sons. This book was released on 2015-08-28 with total page 1616 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive three-volume handbook brings together a review of the current state together with the latest developments in sol-gel technology to put forward new ideas. The first volume, dedicated to synthesis and shaping, gives an in-depth overview of the wet-chemical processes that constitute the core of the sol-gel method and presents the various pathways for the successful synthesis of inorganic and hybrid organic-inorganic materials, bio- and bio-inspired materials, powders, particles and fibers as well as sol-gel derived thin films, coatings and surfaces. The second volume deals with the mechanical, optical, electrical and magnetic properties of sol-gel derived materials and the methods for their characterization such as diffraction methods and nuclear magnetic resonance, infrared and Raman spectroscopies. The third volume concentrates on the various applications in the fields of membrane science, catalysis, energy research, biomaterials science, biomedicine, photonics and electronics.

Download or read book Handbook of sol gel science and technology 1 Sol gel processing written by Sumio Sakka and published by Springer Science & Business Media. This book was released on 2005 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since Dr. Disiich of Germany prepared a glass lens by the sol-gel method around 1970, sol-gel science and technology has continued to develop. Since then this field has seen remarkable technical developments as well as a broadening of the applications of sol-gel science and technology. There is a growing need for a comprehensive reference that treats both the fundamentals and the applications, and this is the aim of "Handbook of Sol-Gel Science and Technology."The primary purpose of sol-gel science and technology is to produce materials, active and non-active including optical, electronic, chemical, sensor, bio- and structural materials. This means that sol-gel science and technology is related to all kinds of manufacturing industries. Thus Volume 1, "Sol-Gel Processing," is devoted to general aspects of processing. Newly developed materials such as organic-inorganic hybrids, photonic crystals, ferroelectric coatings, photocatalysts will be covered. Topics in this volume include: Volume 2, "Characterization of Sol-Gel Materials and Products, "highlights the important fact that useful materials are only produced when characterization is tied to processing. Furthermore, characterization is essential to the understanding of nanostructured materials, and sol-gel technology is a most important technology in this new field. Since nanomaterials display their functional property based on their nano- and micro-structure, "characterization" is very important. Topics found in Volume 2 include: Sol-gel technology is a versatile technology, making it possible to produce a wide variety of materials and to provide existing substances with novel properties. This technology was applied to producingnovel materials, for example organic-inorganic hybrids, which are quite difficult to make by other fabricating techniques, and it was also applied to producing materials based on high temperature superconducting oxides. "Applications of Sol-Gel Technology," (Volume 3), will cover applications such as:

Download or read book Sol gel Processing Microstructural Development and Electrical Properties of Ferroelectric Lead Zirconate titanate Thin Films written by Cheng-Chen Hsueh and published by . This book was released on 1991 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ceramic Abstracts written by and published by . This book was released on 1999 with total page 950 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sol Gel Science written by C. Jeffrey Brinker and published by Academic Press. This book was released on 2013-10-22 with total page 925 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sol-Gel Science: The Physics and Chemistry of Sol-Gel Processing presents the physical and chemical principles of the sol-gel process. The book emphasizes the science behind sol-gel processing with a chapter devoted to applications. The first chapter introduces basic terminology, provides a brief historical sketch, and identifies some excellent texts for background reading. Chapters 2 and 3 discuss the mechanisms of hydrolysis and condensation for nonsilicate and silicate systems. Chapter 4 deals with stabilization and gelation of sols. Chapter 5 reviews theories of gelation and examines the predicted and observed changes in the properties of a sol in the vicinity of the gel point. Chapter 6 describes the changes in structure and properties that occur during aging of a gel in its pore liquor (or some other liquid). The discussion of drying is divided into two parts, with the theory concentrated in Chapter 7 and the phenomenology in Chapter 8. The structure of dried gels is explored in Chapter 9. Chapter 10 shows the possibility of using the gel as a substrate for chemical reactions or of modifying the bulk composition of the resulting ceramic by performing a surface reaction (such as nitridation) on the gel. Chapter 11 reviews the theory and practice of sintering, describing the mechanisms that govern densification of amorphous and crystalline materials, and showing the advantages of avoiding crystallization before sintering is complete. The properties of gel-derived and conventional ceramics are discussed in Chapter 12. The preparation of films is such an important aspect of sol-gel technology that the fundamentals of film formation are treated at length in Chapter 13. Films and other applications are briefly reviewed in Chapter 14. Materials scientists and researchers in the field of sol-gel processing will find the book invaluable.

Download or read book Sol Gel Synthesis and Processing written by Sridhar Komarneni and published by Wiley-American Ceramic Society. This book was released on 1998-02-28 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Proceedings of the International Symposium on Sol-Gel Processing, held at the 100th Annual Meeting of the American Ceramic Society in Cincinnati, Ohio, May 3-6, 1998"--verso of T.p.

Download or read book Effects of Solution Precursor Nature on Sol gel Derived PZT Thin Film Crystallization Behavior and Properties written by and published by . This book was released on 1995 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: In fabricating lead zirconate titanate (PZT) films for nonvolatile memories and decoupling capacitors, various deposition methods have been investigated. Each can produce films with acceptable dielectric and ferroelectric properties, but sol-gel methods offer excellent control of film stoichiometry and coating uniformity. The sol-gel approaches for PZT film fabrication fall into two categories: processes that use 2-methoxyethanol as a solvent, and processes that use chelating agents, such as acetic acid, for reducing the hydrolysis sensitivity of the alkoxide compounds. Due to concerns about the toxicity of 2-methoxyethanol, we have concentrated on the second category. It was found that, in addition to reducing the hydrolysis sensitivity, the chelating agents serves to define the processing behavior of the films: film consolidation after deposition and densification and crystallization during heat treatment. This paper discusses the relations between precursor structure (reactions between chelating agents and the metal alkoxide starting reagents) and film consolidation, densification, and crystallization.