Factory quartz glass and articles thereof
Correct measurements through regular inspections of the spectrometer with certified reference material. Optical immersion probes and measuring cells for spectroscopic analysis in laboratory, pilot plant and process. Cuvettes serve as vessels for liquid or gaseous substances where the interaction of light is to be observed, examined or measured. To ensure that these photometric measurements are not influenced by unknown impurities, the highest demands must be placed on the cleanliness of the cuvettes.VIDEO ON THE TOPIC: quartz stone commentaires-composes.com4
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- US5389582A - Cristobalite reinforcement of quartz glass - Google Patents
- US2702750A - Manufacture of articles from substances containing silica - Google Patents
- All 2,493 US products targeted by China’s new 25% tariffs
- Heraeus Conamic - backbone of the information age
- Export Impact For Good
- P1 Firm Details
- The 286 products that escaped Trump’s tariffs
- The 286 products that escaped Trump’s tariffs
US5389582A - Cristobalite reinforcement of quartz glass - Google Patents
Experiments in which a glass cylinder was sandwiched between two mineral cylinders—quartz and albite, quartz and K-feldspar, or albite and corundum—tested the validity of the inferred directions of uncoupled diffusion and explored long-range chemical communication in the melt via chemical potential gradients. The information provided here determines the rate at which crustal anatexis can occur when sufficient heat is supplied and diffusion is the only mass transport mixing process in the melt.
Slower diffusion in H 2 O-undersaturated melts will increase this time frame. Mechanical mixing during melt segregation and transport Wickham, a , b ; Brown et al. Lesher, ; Shaw, Understanding the diffusive transport properties of silicate melts helps to constrain the time frames of some igneous processes that entail the production or homogenization of silicate liquids e. Watson, , ; Baker, , ; Sawyer, ; Lesher, ; Barbero et al.
Knowledge of the diffusive transport properties of granitic melts can shed light on speciation in the melt that can be tested or augmented by spectroscopic studies [e.
Accurate information on liquid speciation is essential for constructing rigorous thermodynamic models. Chakraborty, This study complements that of Acosta-Vigil et al. Chakraborty, in H 2 O-saturated haplogranitic melts at typical crustal anatectic temperatures.
Concentration profiles of the oxide components in the glass quenched melt were measured perpendicular to the mineral—glass interfaces. Published solutions to the diffusion equations were used, together with constraints provided from the evolution of concentration profiles with time, to determine part of the diffusion matrix of the system by inversion of the concentration profiles.
The results confirm the distinctly different behavior of Na and K in relation to Al gradients in the melt Acosta-Vigil et al. Table 1 shows mean electron microprobe analyses of minerals and starting anhydrous glass and some experimental glasses.
Cores were cleaned with de-ionized, ultra-filtered DIUF water in an ultrasonic bath. Capsules were sealed by d. Capsules were placed with their long axes parallel to the vessels, such that the mineral—melt interfaces remained near vertical during the experiment.
After quench, capsules were weighed, punctured, placed in a desiccator overnight, and then reweighed to check for the loss of free water indicating H 2 O saturation at run conditions and providing an estimate of water dissolved into the melt. The single-mineral dissolution experiments were conducted to obtain concentration gradients of the different oxide components in the liquid resulting from diffusion along different directions in composition space defined by mineral—glass vectors.
The sandwiched glass experiments were conducted to test the validity of the inferred directions of uncoupled diffusion in the melt see below , to explore the long-range chemical communication in melt via chemical potential gradients e. Mehnert et al. Starting materials and experimental products were analyzed with a Cameca SX electron microprobe at the University of Oklahoma.
Sodium, potassium, and aluminum were concurrently analyzed first to minimize alkali volatilization and attendant changes in elemental ratios.
The experiments involved dissolution of the starting mineral phase s into the melt, with no significant new mineral growth in the silicate liquid or at the mineral—melt interface. Back-scattered electron imaging shows no recrystallization or alteration of quartz, orthoclase, or corundum during the experiments.
Albite, however, shows minor recrystallization to a binary feldspar solid solution, mostly along fractures connected to the interface Fig. With this exception, relict feldspars close to the interface melt show no change in composition with respect to the starting feldspars Table 3. Back-scattered electron images of mineral—glass interfaces in experiments Acasi albite dissolution and Acasi orthoclase dissolution.
Light gray domains in Acasi correspond to a binary feldspar recrystallized after the starting albite. Mineral symbols are taken from Kretz ; gl, glass. Dissolution rates were calculated by mass balance using starting and final SiO 2 and Al 2 O 3 concentration profiles in the glass, together with quartz, albite, and orthoclase compositions.
Retreat of the quartz—, albite—, and orthoclase—melt interfaces dissolution distance vs the square root of time, calculated by mass balance based on starting and final silica and alumina concentration profiles in the glasses.
Albite shows signs of very local equilibration with the interface melt in the timeframe of the experiments; orthoclase does not. Each point represents the mean value of three analyses along the interface. Numbers close to the points refer to run duration in hours. The dissolution of quartz vs feldspars produced contrasting concentration profiles in the melt.
Quartz dissolution involved mainly addition of silica and dilution of alumina and alkalis in the boundary layer. Beyond the boundary layer, the concentrations of silica, alumina, and alkalis are similar to those in the starting hydrated glass Table 4 , Fig.
These facts indicate that diffusion of silicon occurs only within the boundary layer and does not involve coupling with any other component in melt. Composition of glasses in the quartz dissolution experiments as a function of experimental time and distance to the quartz—glass interface. In this and subsequent figures, each concentration profile represents the mean values of three analytical transverses perpendicular to the interface; the compositions are shown as obtained from the electron microprobe; the dashed lines refer to concentrations or molar ratios in the starting H 2 O-saturated metaluminous melt; analytical uncertainties error bars are shown within rectangles analytical uncertainties are equal to or smaller than the symbols when not shown.
Left interface corresponds to quartz—glass in Acasi and Acasi , and corundum—glass in Acasi see Fig. Right interface corresponds to albite—glass in Acasi and Acasi , and orthoclase—glass in Acasi see Fig.
Upon dissolution of albite, the concentrations of alumina, sodium, and potassium in the glass increase monotonically within the boundary layer toward the mineral—glass interface, whereas silica decreases Table 4 , Fig. This further reveals 1 that alkalis can diffuse much faster than silicon and aluminum, and 2 that aluminum and sodium decouple upon entering the melt during the dissolution of albite. Although the shapes of the concentration profiles for both alkalis are similar in albite dissolution runs, the direction of diffusion for sodium is opposite to that for diffusion of potassium: sodium diffuses downhill away from the interface, producing an increase in its concentration throughout the melt column with respect to the starting glass, and potassium diffuses uphill toward the interface, with an overall decrease in its concentration Fig.
These changes in concentration are above analytical uncertainties. Composition of glasses in the albite dissolution experiments as a function of experimental time and distance to the albite—glass interface. Orthoclase dissolution experiments yield observations comparable with those for albite Fig.
The migration of aluminum and silicon takes place only within the boundary layer, whereas alkalis diffuse throughout the entire melt reservoir. Upon entering the melt, aluminum and potassium from orthoclase become decoupled.
Potassium diffuses down its concentration gradient away from the interface, increasing its concentration throughout the melt, whereas sodium diffuses uphill toward the interface, decreasing its concentration in the melt beyond the boundary layer. Composition of glasses in the orthoclase dissolution experiments as a function of experimental time and distance to the orthoclase—glass interface.
Metaluminous haplogranite system. The experiments in which glass was sandwiched between quartz and feldspars produced results comparable with those of the single-mineral dissolution experiments Table 4 , Fig. Silica concentration in the glass increases toward quartz and decreases toward feldspars.
Alumina and alkali concentrations increase toward feldspars and decrease toward quartz. The ASI is constant throughout the glass except in the boundary layers close to feldspars, where it increases slightly toward the interfaces, although it remains constant within analytical uncertainty. Composition of glasses sandwiched between two mineral phases, as a function of distance to one of the interfaces.
Peraluminous haplogranite system. The only significant differences between the sandwich experiment in the peraluminous system corundum—glass—albite and those in the metaluminous system are the greater ASI values throughout the entire glass and the notable increase in ASI within the boundary layers toward corundum and, importantly, toward albite as well Table 4 , Fig. The starting glass cores are anhydrous.
For the correct interpretation of results, it is important to determine if hydration—melting of the glass cores is complete prior to mineral dissolution. A study of H 2 O diffusion Acosta-Vigil et al. Therefore, mineral dissolution in the current experiments is initiated in homogeneous, hydrous liquid.
During initial cold pressurization of capsules, the gold or platinum tubes collapse around the length of the cores, squeezing almost all of the added water to strain shadows at the ends of the capsule. No irregular concentration profiles corresponding to sidewall diffusion from the melt—capsule interface were found in the current experiments [compare with fig.
These observations confirm that neither an excess H 2 O fluid phase in the capsule nor starting with anhydrous glass cylinders has any effect on the resultant concentration profiles in experimental glasses. There are three main processes that potentially can govern the concentration profiles of melt components during the dissolution of a mineral phase into the melt: 1 the interface reaction or process by which mineral components detach from the mineral surface to enter the melt; 2 the diffusion of components through the melt; 3 convection in the melt e.
Donaldson, ; Zhang et al. Convection did not occur or was not significant in these experiments because: 1 the concentrations of the oxide components in the glasses vary monotonically with the distance from the mineral—melt interface compare with Shaw, ; 2 with increasing time the width of the melt boundary layer increases whereas the mineral dissolution rate decreases [ Table 2 and Fig.
There are three conditions to be fulfilled for the profiles to be solely controlled by diffusion in the melt: 1 the composition of the interface melt is at the liquidus of the dissolving mineral phase at the conditions of the experiments; 2 the retreat of the mineral—melt interface is proportional to the square root of time; 3 the concentration profiles overlap when plotted against distance normalized to the square root of time e.
Crank, ; Zhang et al. Regarding condition 1 , Fig. However, we call attention to the observation that concentration profiles in albite and orthoclase dissolution experiments cannot rigorously overlap when plotted against distance normalized to time, because of the uphill diffusion of melt components throughout the entire melt column and the finite nature of the melt reservoir.
Condition 3 seems to hold only for the case of semi-infinite melt reservoirs see Acosta-Vigil et al. Concentration of oxide components as a function of time and distance to the mineral—glass interface normalized to the square root of time, in glasses of the quartz, albite, and orthoclase dissolution experiments.
A background on multicomponent chemical diffusion can be found elsewhere e. The current modeling aims to elucidate all or part of the diffusion matrix, D. Our approach to gain information about the eigenvectors is different from previous ones. Rather than diffusion couples, we began with dissolution experiments utilizing phases that contain only a single oxide component: corundum Acosta-Vigil et al. This approach produces relatively simple concentration profiles in the melt because diffusion occurs mainly along the single uncoupled direction that is responsible for the diffusive transport of the oxide component SiO 2 , Al 2 O 3 , H 2 O added to the interface melt.
Therefore, information about individual directions of uncoupled diffusion in the system can be obtained directly from the study of experimental concentration profiles. Diffusion data along additional directions of uncoupled diffusion in compositional space are then derived by dissolution of more complex mineral phases e. K or Na to the previously defined system. In this manner, diffusion data for all of the principal components in the granitic system can be derived from a succession of glass hydration—melting and single-mineral dissolution experiments.
These results can be tested and verified afterward via additional complex mineral dissolution experiments e. Acosta-Vigil et al. The eigenvectors represent a new set of chemical components whose fluxes are independent of each other e.
Each eigenvector is related to any other set of chemical components e. For instance, P ij is a coefficient of P that refers to the proportion of the old component i in the eigenvector j. As eigenvectors represent directions of uncoupled diffusion, these coefficients refer to the relative amounts of old components migrating at the same time and speed see also Mungall et al.
We rely on this observation to gain information on the eigenvectors matrix P from the analysis of the oxide concentration profiles. Finally, to elucidate the eigenvalues of D we inverted the concentration profiles in melt produced by diffusion along three directions in composition space: quartz—, albite—, and orthoclase—water-saturated metaluminous haplogranite Fig.
The procedure has been used previously e. During inversion of concentration profiles we used the information gained on the eigenvectors as additional constraints. Mineral symbols are taken from Kretz
US2702750A - Manufacture of articles from substances containing silica - Google Patents
Email: glass quartzltd. Airmail prices on request. Periodicals postage paid at Emigsville, PA.
Experiments in which a glass cylinder was sandwiched between two mineral cylinders—quartz and albite, quartz and K-feldspar, or albite and corundum—tested the validity of the inferred directions of uncoupled diffusion and explored long-range chemical communication in the melt via chemical potential gradients. The information provided here determines the rate at which crustal anatexis can occur when sufficient heat is supplied and diffusion is the only mass transport mixing process in the melt. Slower diffusion in H 2 O-undersaturated melts will increase this time frame. Mechanical mixing during melt segregation and transport Wickham, a , b ; Brown et al.
All 2,493 US products targeted by China’s new 25% tariffs
Application August 6, , Serial No. More than one metal may be included in the reaction. The raw material silica may be in combined or uncornbined state. For instance it may be sand, quartz, silica glass or pure fused silica, which are examples of bodies composed largely of free silica, metallic s licates, porcelain, ceramics, which are exemplary o f bod1es containing substantial quantities of combined silica. Porcelain, for instance, contains kao'line which is a hydrated aluminum silicate, clay, feldspar which is a potassium aluminum silicate, and some quartz. Some of the metallic silicates are preferred over others; for instance nickel and chromium silicates give good results whereas zircon silicates are less satisfactory. The reducing metals may be employed in the process, and they are illustrated by aluminum, magnesium, the alkali metals sodium, potassium and lithium, and by the alkaline earth metals calcium, barium, and strontium. The reducing metals may be used pure or in alloys or mixtures with other active metals or with auxiliary metals. Alloys may be used for the reduction and may contain Al or Mg with one or several of the other reducingmetals.
Heraeus Conamic - backbone of the information age
This application is a continuation-in-part of application Ser. The present invention relates to the use of cristobalite in refractory quartz glass articles and in high temperature processes such as are used in the semiconductor industry and in the investment casting industry. It involves the manufacture or fabrication of a wide variety of refractory articles. One embodiment of the invention relates to a unique crucible for use in a Czochralski Cz crystal-growing process. While cristobalite has certain advantageous physical properties at high temperatures, it creates serious problems in refractory silica articles because of the extreme volume changes during the crystallographic alpha-beta inversion.
Effective date of registration : Address after : Tokyo, Japan, Japan. Patentee after : Sumco Corp.
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Abstract Quartz glass is considered as model ceramic material for selective laser melting SLM. Single beads of fused powder bonded with a continuous substrate of the same material are obtained. Neither the beads nor the substrates near them are cracked. Low closed porosity in the beads and detachment of the bead borders from the substrate are observed. The quality of the obtained beads is estimated to be sufficient for fabrication of three-dimensional parts by SLM. Comparison with calculations of heat transfer and evaporation reveals that the mass and the energy losses by evaporation are considerable and that the substrate surface should be locally heated up to K for strong bonding with the bead.
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The glasses fall into three types according to the fluxing agents used: mineral natron, soda-rich plant ash, and a combination of soda ash and lead. The natron glasses can be assigned to various established primary production groups of eastern Mediterranean provenance. Different types of plant ash glasses indicate differences in the silica source as well as the plant ash component, reflecting changing supply mechanisms. While the earlier plant ash groups can be related to Islamic glasses from the Near East, both in terms of typology and composition, the chemical signature of the later samples appear to be specific to glass from the Iberian Peninsula. This has important implications for our understanding of the emerging glass industry in Spain and the distribution patterns of glass groups and raw materials.
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The 286 products that escaped Trump’s tariffs
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The 286 products that escaped Trump’s tariffs
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