scholarly journals Fundamental Studies on Phosphate Glasses of High Chemical Durability and Their Manufacture (I)

1953 ◽  
Vol 61 (690) ◽  
pp. 621-624 ◽  
Author(s):  
Kentaro TAKAHASHI ◽  
Kenji IIDA ◽  
Yuichi WATANABE ◽  
Maki OGUCHI
Keyword(s):  
Chemical Durability ◽  
Phosphate Glasses ◽  
High Chemical

Preparation of Calcium Phosphate Glasses Containing Nb2O5 and TiO2

2018 ◽  
Vol 782 ◽  
pp. 47-52
Author(s):  
Patrícia Suemi Sato ◽  
Hirotaka Maeda ◽  
Akiko Obata ◽  
Toshihiro Kasuga
Keyword(s):  
Controlled Release ◽  
Calcium Phosphate ◽  
Calcium Titanate ◽  
Chemical Durability ◽  
Phosphate Glasses ◽  
Dissolution Test ◽  
Buffer Solution ◽  
High Chemical ◽  
Positive Effects ◽  
Tris Buffer Solution

60CaO-30P2O5-(10 ̶ x)Nb2O5-xTiO2 (x = 0 ~ 10, mol%) glasses were prepared in order to obtain biomaterials with high chemical durability and therapeutic ions releasability. Dissolution test of these glasses using Tris buffer solution showed the controlled release of niobate ions from Nb2O5-containing glasses and the formation of calcium titanate in some of them. These behavior might induce positive effects for bone regeneration.

Nitrogen/Oxygen Substitution within PO4 Tetrahedra: A Right Answer to the Poor Chemical Durability of Phosphate Glasses

1998 ◽  
Vol 547 ◽  
Author(s):  
A. Le Sauze ◽  
L. Montagne ◽  
G. Palavit ◽  
R. Marchand
Keyword(s):  
Window Glass ◽  
Soda Lime ◽  
Chemical Durability ◽  
Phosphate Glasses ◽  
Processing Temperature ◽  
Melting Temperatures ◽  
Thermal Expansion Coefficients ◽  
Glass Processing ◽  
Alumina Addition ◽  
Oxygen Substitution

AbstractBy using both alumina addition and nitrogen/oxygen substitution within PO4 tetrahedra, it is possible to prepare durable phosphate glasses without affecting their specific properties such as low melting temperatures and high thermal expansion coefficients. In particular, “LiKMgAlPON” nitrogen-rich glass compositions have a chemical durability on the same order as soda lime window glass, associated with a glass processing temperature as low as 800°C.

Design of a Cool Color Glaze for a Solar Reflective Tile

2014 ◽  
Vol 92 ◽  
pp. 159-167
Author(s):  
Chiara Ferrari ◽  
Alberto Muscio ◽  
Cristina Siligardi ◽  
Tiziano Manfredini
Keyword(s):  
Chemical Durability ◽  
Inorganic Pigments ◽  
Heat Island ◽  
High Chemical ◽  
Cool Roof ◽  
Island Effect ◽  
Solar Reflectance ◽  
Thermal Emissivity ◽  
Urban Heat ◽  
Cool Roofs

One of the most common materials-measures to counteract Urban Heat Island Effect can be identified in cool roof: white surface characterized by high solar reflectance and high thermal emissivity. One of the problems for the realization of cool roof is the difficult matching of white color with urban planning needs. In order to better integrate cool roofs into skylines cool colors were developed integrating pigments into cool roof surfaces. Cool roof market is actually dominated by organic based products with optimal solar performances but low durability against ageing. The use of ceramic-based products is crucial in the design of a new durable cool roof thanks to their naturally high thermal emissivity (ε=0.90) and their high chemical durability. The development of a new ceramic-based product made by a traditional porcelain stoneware tile as support, an inorganic engobe was started in the last years. In order to complete the product with a suitable glaze, eight different inorganic pigments were added to three different glazes, each one characterized by different surfaces features. Even if the addition of glazes, and pigments decrease the reflectance values of the solar reflective engobe, some promising results were achieved in this study especially regarding warm colored glazes.

Properties Investigation of Yb3+-Doped Phosphate Glasses for Fiber Laser

2013 ◽  
Vol 573 ◽  
pp. 31-35
Author(s):  
His Wen Yang ◽  
Jin Ming Zhu ◽  
Yu Xiang Tsai ◽  
Chun Hsiung Lin ◽  
Cheng Hsing Hsu ◽  
...  
Keyword(s):  
Refractive Index ◽  
Fluorescence Spectra ◽  
Coefficient Of Thermal Expansion ◽  
Fluorescence Emission ◽  
Softening Temperature ◽  
Chemical Durability ◽  
Phosphate Glasses ◽  
Content Increase ◽  
Glass Softening ◽  
Bridge Oxygen

The physical and optical properties of P2O5-Al2O3-ZnO glasses doped with different concentration of Yb3+ions were investigated. The experimental results indicated that density, chemical durability, glass transition temperature (Tg) and glass softening temperature (Td) of glasses increase with increasing the Yb2O3content of glasses. However, the coefficient of thermal expansion (α) for glasses decrease with increasing the Yb2O3content. From the results of Fourier transform infrared spectroscopy, the numbers of (-P-O-P-) bonds decrease and (-P-O-M+-) bonds increase with increasing the Yb2O3content. Increase of non-bridge oxygen (-P-O-M+-) raise the refractive index of glasses. Moreover, the results of absorption spectra indicate that the absorption peak of glasses are observed at both wavelengths of 916nm and 977nm. As increasing the concentration of Yb2O3, the absorption efficiencies become stronger. In accordance with the results of fluorescence spectra, the fluorescence emission of glasses are detected at wavelengths of 970nm, 995nm, 1020nm and 1048nm, respectively. The intensity of the fluorescence emission peaks significantly decrease at wavelengths of 970nm and 995nm as the concentration of Yb2O3increases. However, the intensity of the fluorescence emission peaks significantly increase at wavelength of 1048nm under the same condition.

scholarly journals Elaboration and characterization of new phosphate glasses based on natural phosphate and red clay: influence of the chemical composition on the chemical durability

2019 ◽  
Vol 9 (3) ◽  
pp. 222-235 ◽  
Author(s):  
Oumaima Jamal Eddine ◽  
Mehdi El Bouchti ◽  
Omar Cherkaoui ◽  
Hassan Hannache ◽  
Said Gmouh
Keyword(s):  
Chemical Composition ◽  
Structural Investigation ◽  
Fluorescence Analysis ◽  
Chemical Durability ◽  
Phosphate Glasses ◽  
Red Clay ◽  
Natural Phosphate ◽  
X Ray ◽  
Quenching Method

New phosphate glass formulations based on Moroccan natural phosphate minerals alone or with Moroccan red clay additive (containing the P2O5-SiO2-CaO-Al2O3-MgO-Fe2O3-K2O-Na2O-TiO2 complex) have been successfully prepared by the quenching method. The chemical composition of each of the elaborated phosphate glasses was determined by X-ray fluorescence analysis (XRF). These investigated phosphate glasses have an excellent homogeneity as was verified by SEM. Their amorphous behavior was confirmed by XRD and DSC. The increase in density and glass transition temperature due to the addition of clay is believed to be related to the crosslinking of the phosphate chains. Structural investigation of these phosphate glasses was carried out using FTIR and Raman spectroscopies. The results obtained show that the composition of these glasses contains a mixture of ultraphosphate and polyphosphate structural units. The concentrations of this mixture depending on the initial composition of the glass components. A correlation between the chemical composition and the chemical durability of the investigated glasses was studied. The results showed that the dissolution rate of the glasses decreases by increasing the clay composition up to a point. This can be explained by assuming the formation of oxygen bridges and strong bonds within the various glasses.

Murataite-based ceramics for actinide waste immobilization

1999 ◽  
Vol 556 ◽  
Author(s):  
S. V. Stefanovsky ◽  
S. V. Yudintse ◽  
B. S. Nikonov ◽  
B. I. Omelianenko ◽  
A. G. Ptashkin
Keyword(s):  
Rare Earth ◽  
Chemical Durability ◽  
Isomorphic Substitution ◽  
Cold Crucible ◽  
Hydrothermal Conditions ◽  
High Chemical ◽  
Ceramic Samples ◽  
Waste Immobilization ◽  
Very High ◽  
Xrd And Tem

AbstractStudying the Synroc, doped with a simulated HLW, we have found, along with conventional Synroc phases (zirconolite, perovskite, hollandite), an extra phase with a stoichiornetry (Ca, Mn, U, TR)4(U, TR, Zr, Ti) 2(AI, Ti)7O22. XRD and TEM study has shown this phase is related to a very rare mineral murataite. In the present work a ceramic based on murataite is studied. The ceramic samples in the system: Ca-Mn-Ti-Zr-U-Ce-AI-Fe-O were produced and examined in details using XRD, SEM/EDS, TEM, and optical microscopy. Total amount of actinide (U) and rare earth (Ce, Gd) elements in the murataite exceeds 20 wt%. Isomorphic substitution schemes in the structures of synthetic and natural murataites are discussed. High isomorphic capacity of the murataite structure towards actinides and REEs, flexibility of its composition, feasibility of synthesis by melting, including a cold crucible melting, and very high chemical durability under hydrothermal conditions make the murataite-based ceramics very promising for actinides and excess weapon Pu fixation.

scholarly journals Nanoporous Glasses for Nuclear Waste Containment

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Thierry Woignier ◽  
Juan Primera ◽  
Jerôme Reynes
Keyword(s):  
Structural Stability ◽  
Nuclear Waste ◽  
Silica Glass ◽  
Glass Structure ◽  
Chemical Species ◽  
Chemical Durability ◽  
High Chemical ◽  
Host Matrix ◽  
Composite Gels ◽  
High Structural Stability

Research is in progress to incorporate nuclear waste in new matrices with high structural stability, resistance to thermal shock, and high chemical durability. Interactions with water are important for materials used as a containment matrix for the radio nuclides. It is indispensable to improve their chemical durability to limit the possible release of radioactive chemical species, if the glass structure is attacked by corrosion. By associating high structural stability and high chemical durability, silica glass optimizes the properties of a suitable host matrix. According to an easy sintering stage, nanoporous glasses such as xerogels, aerogels, and composite gels are alternative ways to synthesize silica glass at relatively low temperatures (≈1,000–1,200°C). Nuclear wastes exist as aqueous salt solutions and we propose using the open pore structure of the nanoporous glass to enable migration of the solution throughout the solid volume. The loaded material is then sintered, thereby trapping the radioactive chemical species. The structure of the sintered materials (glass ceramics) is that of nanocomposites: actinide phases (~100 nm) embedded in a vitreous silica matrix. Our results showed a large improvement in the chemical durability of glass ceramic over conventional nuclear glass.

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