The risk of the increased levels of radioactive radiations determines a special attitude to the atomic energy and radwastes RW and demands the acceptance of cardinal and operative measures on their isolation from people. As regards the glass matrixes, they allow to reduce the volume of the conditioned waste products and to improve sharply physical and chemical properties of the matrix, but at the same time due to an amorphous structure have a number of disadvantages such as: high fragility, presence of numerous structural defects, low homogeneity and density and also rather low radiation resistance. During the last stage the optimal regimes of the extraction of radioactive nuclides by zeolites have been specified on the pilot machine. Thus, in the static and dynamic conditions the significant reduction of LRW volumes up to times with their transformation into a hard phase has been achieved.
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- US20020192422A1 - Glass ceramic composite of mirror blank - Google Patents
- List of manufacturing processes
- US3454386A - Method for making radiation induced crystallized glass - Google Patents
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- Slag-sitall production by a hot-pressing method
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US20020192422A1 - Glass ceramic composite of mirror blank - Google PatentsVIDEO ON THE TOPIC: National Slag Association Iron and Steel Slag Products
July 8, M. Ernsberger, Pittsburgh, Pa. The development of this crystal reduces the average coefiicient of thermal expansion exhibited by the glass-crystal combination in the surface region of the glass.
The lower coefiicient of thermal expansion results in a surface compressive stress, which increases the strength of the glass article. This process is illustrated in US. Patent No. Hood et al. Crystallization not in conjunction with ion exchange techniques has also been suggested.
Belgian Patent No. The method described results in crystalline growth throughout the entire thickness of the glassy matrix, converting the glass article into a complex of crystals and glass wherein the crystals are substantially uniform-1y dispersed in and throughout the entire glassy matrix. The increase in the strength of glass realized by this treatment is not in excess of the strength improvement realized in ordinary tempering operations commonly in commercial use.
This result is not surprising since no surface compression results from uniform crystallization throughout the entire thickness of the article. Another method of strengthening glass articles utilizing crystallization techniques involves the carefully controlled heat treatment over a long period of time of a lithia-alumina-silica glass having approximately the same composition as the B-eucryptite crystal This composition may also contain a certain amount of a nucleating agent, such as TiO The ,B-eucryptite crystal "ice developed exhibits a low coeflicient of thermal expansion, and when present in only the surface portions of a glass article develops a state of high surface compressive stress.
This procedure is illustrated in US. In copending application Ser. Pressau, now abandoned, there is disclosed a method of producing surface crystallization using a thermal gradient technique.
The glass composition disclosed therein when subjected to the thermal gradient heat treatment develops crystals of silica-O in and near the surface zones of the glass article. The silica-O, since they exhibit a lower coefiicient of thermal expansion than the base glass composition, develop a surface compressive zone which increases the strength of the glass article.
The silica-O crystals are nucleated at the surface and at various points within the interior of the glass near the surface. The ciystals developed are randomly oriented and relatively small in size compared to most other crystallization techniques. The crystals produced in this technique are surface nucleated by coating the glass with a titanium nucleating compound.
The surface nucleated crystals grow from the surface into the glass interior to develop the lower coeflicient of thermal expansion surface zone. The characteristic crystalline development is perpendicular to the glass surface and predominantly composed of parallel oriented needle shaped crystals. Ultra-violet radiation has also been used to produce crystallization in certain glass compositions.
These ultraviolet sensitive glasses are heat treated to develop crystalline photographic images in the glass. Such a technique is disclosed in US. The crystals'in this technique are nucleated by photosensitization of goldin the glass. The crystal grown is barium disilicate. Closely related work by Stookey discloses silver and copper photo-sensitive glasses which develop crystals of various lithium compounds.
What has been discovered in the present invention is a method of producing randomly oriented surface and near surface silica-O crystals in glass by subjecting suitable base glass compositions to high energy radiation and subsequent heat treatments.
Broadly, the mechanisms in the present invention begin with a high energy irradiation treatment of a suitable glass to produce photo-electrons 'at metastable levels which are localized due to the high viscosity of the glass. The irradiated glass sample is then heat treated to cause the electrons to migrate to certain metal ions vin the glass to reduce these metal ions to atomic metal. Some of these metal atoms coagulate into aggregates of colloidal size metal particles. A second heat treating operation alters the metal aggregates into crystal nuclei.
The nucleated glass composition is then heat treated in a third operationto promote crystalline growth upon the nuclei so developed in the glass. This invention more particularly relates to crystallizing silica-O in transparent or translucent lithia-soda-alumina-silicate glass compositions.
The crystal, silica-O, developed is the same as that developed in the copending application of Jean Pressau referred to above.
Strength improvement is developed in the present invention by the relatively low coefiicient of thermal expansion exhibited by the silica-O crystal compared to the coefficient of thermal expansion exhibited by the base glass composition. Increased abraded strength of the glass samples is realized in the present invention due to the deep layer of crystallization which can be developed.
Silicia-O is the name given to a type of crystalline structure which is a polymorphic form of SiO A discussion of the nature of the silica-O crystal form can be found in Zeitschrift fur Kristallographie, vol.
III, pp. This form of Si exhibits a structure which is very similar to that of high quartz. The silica-O crystalline structure is metastable at room temperature but occurs commonly at this temperature. The refractive index of silica-O has been determined to be about 1.
This refractive index roughly matches the refractive index of the base glass of the present invention and makes the production of transparent crystallized glass articles possible.
The silica-O crystalline structure can be easily and conclusively identified by its powder diffraction pattern. Silica-O is distinguishable from other polymorphic forms of SiO by the absence of d spacings at about 3. Table I presents powder X- ray data for the members of the silica-O series. In the above table, the hkl integer notation defines a plane in the crystal structure to which the rest of the tabluated data refer.
The d spacing data in angstroms represents the distance between the parallel crystalline planes of the type described by the hkl notation. The crystal plane for which the maximum intensity of reflected radiation occurs is taken arbitrarily to be percent and all other planes have their relative reflected intensity described as a percentage of the most highly reflecting crystalline plane. It denotes the intensity of the reflected radiation of the plane being investigated and I denotes the arbitrary reflectivity standard of percent.
The present method of producing strengthened glass articles begins with fabricating the glass into its final desired configuration by conventional glass forming techniques. Crystal nuclei are then developed in selected portions of the glass article through high energy irradiation and heat treatments.
After the crystal nuclei have been developed, the glass article is further heat treated to promote crystalline growth on the crystal nuclei developed. Some of the earlier crystallization methods related to crystalline growth which predominantly began at the surface of the glass. The number of crystals formed was usually low and generally of a preferential orientation with respect to the plane of the surface. The average crystal size produced was correspondingly relatively large compared to the crystals produced in the present invention.
A comparison of the crystalline structure developed in the present invention and the crystalline structure developed by a typical surface nucleated technique can be seen in the attached photographs FIGURES 1 and 2 in which,. FIGURE 1 is a photograph magnified X of the randomly oriented silica-O crystals developed in and near the surface of a glass article prepared in accordance with the teachings of the present invention and FIGURE 2 is a photograph magnified 80X of the needle-shaped predominantly unidirectional crystals characteristically formed from surface nucleation sites.
The relative location of the surface and interior portions of each glass sample is indicated on each photograph. Random crystalline orientation promotes the development of higher compressive stress than unidirectional crystalline orientation. This result is obtained because in a randomly oriented crystalline layer a higher percentage of the crystals are oriented in a direction such that the C axis is effectively parallel with the surface of the glass.
The C axis of the silica-O crystal exhibits the lowest coetficients of thermal expansion of any of the three crystal axes. Surface nucleated crystals orient themselves such that the C axis of the crystal lowest coefiicient of thermal expansion is perpendicular to the surface of the glass, which is the least desirable orientation to promote surface compressive stress. It is also characteristic of the present invention that the number of individual crystals produced is large and are of a correspondingly smaller average size.
The size of the crystals produced in accordance with the practice of the present invention vary from approximately 0. The smaller crystal size is the direct result of the crystalline growth not being limited to growth only from surface nucleation sites.
The size to which each crystal can grow before contacting another crystal is limited by the number of crystals being formed in that portion of the glass. The earlier the crystals contact each other during their growth, the smaller is the average size of each crystal developed.
The development of a large number of small crystals in the surface of the glass article result in increased strength without substantially decreasing the transparency of the glass article. Moreover, the time required for crystallization is substantially reduced by limiting crystal size growth.
In the present invention control of the radiation and heat treatment operations promote a corresponding control over the percent crystallinity which can be developed in various portions of the glass article. The percent crystallinity developed in and near the surface can be as high as percent or any degree less than that, by varying the total dose of the high energy radiation, and controlling the duration and temperatures of the heat treatments during nucleation and crystalline growth.
The exact mechanisms of the present invention are at the present time not fully understood. Our best, but still incomplete, understanding of the mechanism involved is expressed in the following model. It is known that free electrons have relatively short ranges of penetration in matter even at high energy levels.
Free electrons of an energy of 2 million electron volts have the ability to penetrate only about 2 millimeters into the surface of glass. Bombardment of a material with electrons at an energy level of 2 million electron volts produces heavy ionization in the irradiated material, with especially high and heavy ionization intensity near the end of the penetration range. At these high energy levels, electrons are able to ionize any atoms which may be present in the bombarded material.
In the case of glass, oxide ions bombarded by high ion to form atomic silver or with trivalent cerium ion to form pseudo-cerous ion. If other metals such as gold, copper or platinum are present in the glass they behave similarly to the silver upon being irradiated and heated.
During the first relatively low-temperature heat treatment of the present invention, the distribution of the electrons in the color center trapping sites is disturbed. The color center traps being the least stable are completely emptied of their electrons and decay away. The reduced metal such as atomic silver probably undergoes competing processes of A emptying and B coalescence by diffusion to form stable particles of colloidal silver. The exact role played by cerium in the glass is not clear.
It is theorized secondary electrons, it is believed, are trapped in metastable states to form color centers. Other'secondary electrons combine with metal ions in the glass such as silver of a glass. It is believed that most of these secondary electrons recombine, producing no net effect. Some of the energy electrons probably furnish a great many secondary electrons since they occupy most of the volume that the pseudo-cerous ions contribute to the formation of atomic silver by reducing silver ions during the heat treatment.
There is also the possibility that little or no atomic silver except that formed by the reaction of the pseudocerous ions with the silver ion exists in the glass. This reaction takes place between and C. To develop the proper nucleation sites for the silica-O crystal using the preferred compositions of the present invention requires the presence of titanium dioxide between about 1.
The nucleation also does not occur until a temperature of about C. It is theorized that in nucleation the silver-glass interface promotes the separation of a titania-rich glass phase immediately around the coagulated reduced silver atoms which in turn acts as the nucleus for the silicacrystal.
It is thought that each silver particle becomes embedded in a spherical globule of titania rich glass, perhaps angstroms in diameter during the second heat treatment of the present invention, referred to as the nucleating heat treatment phase of the invention. The silver may, in fact, dissolve in this globule at this time. When the temperature is further raised to approximately C. At this higher temperature the growth of the crystal continues until the heating is discontinued or until the crystals begin to contact each other, whichever occurs first.
Patent registration. Lithium aluminosilicate, e. FIELD: chemistry. Workpieces with an arbitrary shape are moulded and subjected to re-treatment in a slurry with density of 2. Articles are then moulded and heat treated. EFFECT: shorter duration of moulding, low water absorption and high strength of the glass ceramic material of cowlings.
List of manufacturing processes
Jump to navigation. Refractories and Industrial Ceramics v. Experience of operating a periclase-carbon converter lining made from objects produced by RHI by A. Valuev; I. Govgalenko; I. A completed campaign of converter No. Keywords: converter lining; operating parameters; physicochemical properties; converter campaign; slag; wear rate.
US3454386A - Method for making radiation induced crystallized glass - Google Patents
Year of fee payment : 4. Year of fee payment : 8. Year of fee payment : A method for fabricating composite light-weighted glass ceramics, suitable for use as, e. Component pieces are polished then joined at low temperature using a silicate-containing joining liquid.
GOST Inorganic glass and glass crystal materials. Methods for the determination of elastic module at cross static bending. GOST General specification. GOST Bars, strips and reels of tool unalloyed steel. General specifications. GOST Technical rectified ethyl alcohol. GOST R Personal eyes protection means.
Russian export companies database
Patents for C03B 32 - Thermal after-treatment of glass products not provided for in groups , e. CNA Method for manufacturing microlite by using high-silicon iron tailings. CNA Preparation method of novel imporous nano microcrystalline glass decorative plate. US Reinforcing method of silica glass substance and reinforced silica glass crucible.
Following the successful edition in , the Symposium is devoted to academic and industrial partners working on the substitution and recyclability of critical raw materials CRM in electronic, magnetic and energy harvesting devices. Raw materials are the basic, but fundamental, elements for a wealth of current technological applications. New research and development activities are required to improve the fundamental understanding of new material solutions containing reduced or no critical content while maintaining or enhancing the performance of the materials, components and products. The symposium provides an interdisciplinary platform to discuss about CRM alternatives from the modelling, synthesis, characterization, processing and device integration viewpoints. Bringing together researchers from academia and industry we aim at increasing the interaction among scientists, engineers, and students working on different areas of the CRM field that are too often treated separately. The symposium is organized by members of the EIP RESET commitment, and will therefore be included and publicised within the program of activities of the commitment. Resume : Two decades after the development of the blue light-emitting diode LED , LEDs have quickly established themselves as the lighting technology of the future. The high efficiency, spectral tunability, lack of toxic compounds and a small footprint makes them far more attractive than other lighting technologies.
Slag-sitall production by a hot-pressing method
Account Options Sign in. Energy Research Abstracts. Technical Information Center, U. Department of Energy , - Power resources. Selected pages Title Page. Table of Contents.
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Account Options Sign in. Selected pages Page Page Common terms and phrases addition aggregate aluminum amount applications approximately asphalt average building Bureau of Mines carbon cement chemical clay coal composition concentrate concrete construction containing copper costs determined developed disposal economic effect embankment energy equipment evaluated facility feed ferrous Figure fraction fuel furnace glass heat heavy incinerator included increase indicated industry iron laboratory lead less magnetic manufacture material metals method mill mineral mixes obtained operation particles percent plant plastics possible potential present problems properties range recovered recovery recycling reduced refuse removed reported Research residue resource samples sand scrap screen separation shown shows shredded slag slope sludge soil solid waste specific stability steel strength sulfur surface Table tailings temperature tests tion tons unit utilization various waste weight. Popular passages Page - The work described has been carried out as part of the research programme of the Building Research Establishment of the Department of the Environment and this paper is published by permission of the Director. Page 31 - Also they argue that the woods and groves are cut down, for there is need of an endless amount of wood for timbers, machines, and the smelting of metals. And when the woods and groves are felled, then are exterminated the beasts and birds, very many of which furnish a pleasant and agreeable food for man. Further, when the ores are washed, the water which has been used poisons the brooks and streams, and either destroys the fish or drives them away. Therefore the inhabitants of these regions, on account Page 31
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The invention relates to a flexible article suitable for producing substrates of flexible devices and the production process thereof. Flexibility is the trend of development of electronic devices. The substrate of a flexible device can be glass, metal foil and polymer. Polymer has flexibility and high surface smooth, but its temperature stability is low, not meeting the processing requirements of flexible devices, such as displays, lighting equipment, solar cells and so on.
This tree lists various manufacturing processes arranged by similarity of function. Main articles: Imaging and Coating. From Wikipedia, the free encyclopedia.
The main finishing materials in modern construction include finishing mortars and concretes ; natural and artificial masonry materials ; decorative ceramics ; materials and items made from wood, paper, glass, plastic, and metals; and paints and varnishes. Finishing materials are usually designed for interior or exterior finishing ; some materials are used for both for example, natural decorative stone, ceramic materials, and architectural glass. A special group consists of materials and items for covering floors , which must meet a number of specific requirements negligible wear , high impact strength, and so on. Finishing materials also include acoustic materials , which are used simultaneously as sound-absorbing coatings and as a decorative finish for the interiors of theaters, concert halls, and motion-picture theaters.