Phosphate Glasses, Correlation between Structure and Chemical Durability PDF Download
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Author: Said AQDIM
Publisher: Scientific Research Publishing, Inc. USA
ISBN: 1649974337
Category : Antiques & Collectibles
Languages : en
Pages : 274
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Book Description
Author: Said AQDIM
Publisher: Scientific Research Publishing, Inc. USA
ISBN: 1649974337
Category : Antiques & Collectibles
Languages : en
Pages : 274
Get Book Here
Book Description
Author: Aqdim Said AQDIM
Publisher:
ISBN: 9781649974327
Category :
Languages : en
Pages : 0
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Book Description
Author: Charmayne Elizabeth Smith
Publisher:
ISBN:
Category : Glass-ceramics
Languages : en
Pages : 180
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Book Description
"This dissertation focuses on the properties and structures of ternary zinc phosphate glasses that have recently been investigated as substrates for femto-second (fs) laser writing. Although these glasses have potential for use as optical substrates, their poor chemical properties limit their applications. In this work, ternary zinc phosphate glasses were studied to find compositions with enhanced chemical durability and the properties and structures of the investigated glasses are reported. Paper 1 and Paper 2 include the first systematic studies of the properties, structures of zinc aluminophosphate (ZAP) glasses and phase relationships in the ZnO-Al2O3-P2O5 system, respectively. Adding alumina to a Zn-metaphosphate glass reduces dissolution rates in water by 4 orders of magnitude and increases the glass transition temperatures. The average Al coordination number can be predicted from a structural model that considers the number of non-bridging oxygens to coordinate metal cations, and this work is the first reported use of this model for a ternary phosphate glass. Paper 3 is the first systematic study of how the properties and structures of zinc magnesium polyphosphate glasses change when MgO replaces ZnO for compositions with fixed O/P ratios. The Mg2 and Zn2+ ions have similar field strengths, but have much different effects on glass properties that are discussed in terms of relative polarizabilities (refractivities) and electron configurations of the Mg2+ and Zn2+ ions. In Paper 4, the creation of electronic defects in zinc phosphate glasses by exposure to ultraviolet and x-ray radiation is described. The nature of the defects formed is dependent on the glass composition and similar defects are created when these glasses are exposed to femto-second laser radiation."--Abstract, page iv.
Author: J. David Musgraves
Publisher: Springer
ISBN: 9783319937267
Category : Technology & Engineering
Languages : en
Pages : 1590
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Book Description
This handbook provides comprehensive treatment of the current state of glass science from the leading experts in the field. Opening with an enlightening contribution on the history of glass, the volume is then divided into eight parts. The first part covers fundamental properties, from the current understanding of the thermodynamics of the amorphous state, kinetics, and linear and nonlinear optical properties through colors, photosensitivity, and chemical durability. The second part provides dedicated chapters on each individual glass type, covering traditional systems like silicates and other oxide systems, as well as novel hybrid amorphous materials and spin glasses. The third part features detailed descriptions of modern characterization techniques for understanding this complex state of matter. The fourth part covers modeling, from first-principles calculations through molecular dynamics simulations, and statistical modeling. The fifth part presents a range of laboratory and industrial glass processing methods. The remaining parts cover a wide and representative range of applications areas from optics and photonics through environment, energy, architecture, and sensing. Written by the leading international experts in the field, the Springer Handbook of Glass represents an invaluable resource for graduate students through academic and industry researchers working in photonics, optoelectronics, materials science, energy, architecture, and more.
Author: Richard C. Ropp
Publisher: Elsevier
ISBN: 1483291391
Category : Technology & Engineering
Languages : en
Pages : 336
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Book Description
The author describes a novel method of preparing hydrolysis-stable non-silicate glasses which is based on experimental work accomplished over the past twenty years. As such, the method is the beginning of a new approach to glass-making by the use of a molecularly-polymerizable precursor. The book elucidates the technical details required to produce such molecularly-polymerized glasses from carefully prepared inorganic molecular monomers. Essentially, only silicate-based glasses have been known to be stable, whereas non-silicate glasses could not be attributed with such properties. Such glasses have, therefore, not found widespread usage in industry. The new phosphate glasses described here exhibit stabilities superior to many of the silicate glasses. For example, the nuclear-waste glass shows no measurable loss at all in boiling water, something entirely foreign to the zinc borosilicate glasses developed for nuclear waste encapsulation in the U.S. by Battelle-Northwest. The exceptional stability of the new glasses is achieved by selecting an inorganic compound capable of being polymerized, and then causing it to polymerize in a proper manner, in the absence of chain-stoppers. To obtain glasses equal or superior in hydrolysis stability to silicate-based systems it is imperative to employ molecular polymerization in situ, starting from carefully prepared precursors of exact stoichiometric proportion. Researchers in glass and glass properties will find this volume extremely useful and those involved in organic polymers will be intrigued by the similarities and disparities of the two systems.
Author: Austin Lim
Publisher:
ISBN:
Category : Glass-ceramics
Languages : en
Pages : 166
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Book Description
"The main objective of this research was to evaluate the properties and structures of glasses from the stannous (SnO) phosphate system for possible use in low temperature optical applications. Glasses in the binary xSnO-(100-x)P2O5 system (50[less than or equal to]x[less than or equal to]70) were prepared and their thermal and optical properties were evaluated. Differences in glass transition temperatures (T[subscript g]) measured here and reported in the literature were explained by differences in the residual water content in the glasses, as determined by infrared spectroscopy. In general, increasing the SnO content of the binary glasses increased the refractive index and the glass transition temperature, and reduced the residual water content, producing glasses that are more chemically stable. Raman spectroscopy showed that the chain-length of the average phosphate anion decreased with increasing SnO content. The addition of B2O3 to a Sn(II)-pyrophosphate base glass (x= 67) improves the aqueous dissolution rate by an order of magnitude. The impact of these compositional changes on the optical and thermal properties depends on how the borate is added. Raman and nuclear magnetic resonance spectroscopies reveal that boron is initially incorporated into the glass network in tetrahedral sites and the pyrophosphate anions are converted to orthophosphate anions. The effects of the addition of Ga2O3 and Sb2O3 on the properties of the tin phosphate glasses were also determined. In general, the addition of these modifying oxides increase the glass transition temperature from around 250°C to 350°C, and the refractive index (nD) was in the range 1.75-1.85, depending on glass composition. The chemical durability of these modified glasses was similar to those modified by B2O3-additions. Raman spectroscopy revealed the formation of isolated orthophosphate anions in the formation of Ga (Sb)-O-P glass networks"--Abstract, leaf iv.
Author: Akiko Obata
Publisher: Royal Society of Chemistry
ISBN: 1839161647
Category : Technology & Engineering
Languages : en
Pages : 297
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Book Description
Inorganic glasses are successfully used in the biomedical field, in particular degradable glasses have found applications in tissue engineering, bone regeneration and tooth remineralisation. Silicate glasses are the most commonly used ones but phosphate and borate glasses are attracting more and more interest owing to their special properties, differing from those of silicate bio-glasses. Phosphate and borate glasses thus open up potential routes for new therapeutic applications. This book focuses on these emerging materials. Bridging the phosphate and borate glasses communities, this book provides a fundamental treatment of atomic structure and physicochemical properties before highlighting their current and potential future applications. Phosphate and borate glasses not only feature a broader range of glass formation than silicate glasses. Their ability to completely dissolve in water with the solubility varying over orders of magnitude with compositional changes, makes them exciting materials for delivering therapeutic agents into the human body. Biomaterials scientists working in glasses, hard tissue engineering and regenerative medicine will find this a must-have book to own, alongside their more traditional silicate glass tomes.
Author: Dahiana Andrea Avila Salazar
Publisher:
ISBN:
Category :
Languages : de
Pages : 0
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Book Description
The doctoral thesis comprises a study of the relationships between structure and dissolution behaviour of phosphate and bioactive glasses by employing analytical techniques such as electron paramagnetic resonance (EPR), liquid NMR, solid-state MAS NMR and paramagnetic NMR spectroscopy, among others. The understanding of the corrosion processes of phosphate glasses is important for their technological applications, e.g. drug delivery, antibacterials and tissue engineering. In the present work, the NMR findings provided insights about the role of cations on the mechanism of hydrolysis of phosphate glasses. The incorporation of cobalt into glasses is a new approach to overcome the vascularization limitation in tissue engineering by stimulating the production of blood vessels. These glasses are also interesting as semiconductors, optical devices and solid-state lasers, among others. This work shows that structural (i.e. thermal) properties of cobalt phosphate glasses with constant basicity are dictated by the coordination number of Co2+ sites. The second part of the study on cobalt phosphate glasses is in publication process under the title: "Co2+ as an internal paramagnetic 31P NMR probe for structural analysis of cobalt-phosphate glasses in the solid-state and leachate solutions". This work presents a new approach to investigate the mechanism of dissolution of phosphate glasses based on the paramagnetic effects. Accordingly, features such as the spin-orbit (SO) coupling, zero-field splitting (ZFS) and symmetry of Co2+ sites are correlated to the paramagnetic shift, paramagnetic relaxation enhancement (PRE) and broadening effects on the spectra. That allows the assessment of the distribution of Co2+ ions in the glass network. Additionally, it enables monitoring structural dynamics of phosphate complexes in solution, including conformational changes, upon ligand binding recognition under different conditions, i.e. buffer aqueous solutions (Tris, EDTA).
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
There is ongoing research into calcium phosphate glasses as possible candidates for use in dental restoration and in the field of bone implants. This is due to the fact that calcium phosphate glasses have many useful properties such as bioactivity, biocompatibility, bioresorbability and non toxicity. However, on the other hand they are also known to fail catastrophically and therefore cannot be used in load bearing applications and are limited as coatings to metallic substrates. Calcium phosphate glasses with different types of oxides such as magnesium, [27-28, 30-34] sodium, [14, 36-40] fluorine [41-42] in the presence of titania have been used in research to investigate whether addition of these oxides can help improve the properties of the glasses. It has been shown that calcium phosphate glasses containing fluorine have shown to produce fluoroapatite which is beneficial as it is known to be one of the ways in order to improve chemical durability of calcium phosphate glass-ceramics. [41-42] In the present study, type A glass and glass-ceramics demonstrated the effect of TiO2 addition with reduction of calcium to phosphorus ratio and type B glass and glass-ceramics demonstrated the effect of TiO2 addition with constant calcium to phosphorus ratio on the structure of fluorine containing calcium phosphate glasses and glass-ceramics. The TiO2 addition in type A took place in 5 %, 15 % and 20 % molar content of TiO2 and in type B, TiO2 was added to glasses in 4.76 %, 11.11 %, 16.66 % and 20 % molar content of TiO2. FTIR, DSC, XRD, ESEM and TGA (performed only on amorphous glasses) were used to characterise the glasses and glass-ceramics produced. DSC and density measurements showed that when 15 mol % TiO2 was added in type A; it caused disruption in the glass network which was confirmed by a reduction in the Tg. When TiO2 was added into the glass in type B, there was a general increase in Tg observed which confirmed that TiO2 might strengthen the glass network. XRD re.
Author: James E Shelby
Publisher: Royal Society of Chemistry
ISBN: 1782625119
Category : Technology & Engineering
Languages : en
Pages : 320
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Book Description
This book provides a concise and inexpensive introduction for an undergraduate course in glass science and technology. The level of the book has deliberately been maintained at the introductory level to avoid confusion of the student by inclusion of more advanced material, and is unique in that its text is limited to the amount suitable for a one term course for students in materials science, ceramics or inorganic chemistry. The contents cover the fundamental topics of importance in glass science and technology, including glass formation, crystallization, phase separation and structure of glasses. Additional chapters discuss the most important properties of glasses, including discussion of physical, optical, electrical, chemical and mechanical properties. A final chapter provides an introduction to a number of methods used to form technical glasses, including glass sheet, bottles, insulation fibre, optical fibres and other common commercial products. In addition, the book contains discussion of the effects of phase separation and crystallization on the properties of glasses, which is neglected in other texts. Although intended primarily as a textbook, Introduction to Glass Science and Technology will also be invaluable to the engineer or scientist who desires more knowledge regarding the formation, properties and production of glass.
