KR20190034521A - Glass member with a user-customized composition profile and method of making same - Google Patents

Abstract

In accordance with one embodiment, the method includes forming a structure by printing an ink comprising a glass-forming material, and heat treating the formed structure to convert the glass-forming material to glass.

Description

Glass member with a user-customized composition profile and method of making same

The United States Government has requested the United States Department of Energy to operate the Lawrence Livermore National Laboratory under the contract number DE-AC52-07NA27344 of Lawrence Livermore National Security, .

The present invention relates to a glass member, and more particularly to an optical and non-optical glass member having a user-tailored composition profile and a method of manufacturing the same.

Typically, the gradient of the material composition is introduced either axially by (1) fusing together multiple layers having a homogeneous composition together, or (2) introducing a species (typically small and fast diffusing ions) Gel or solid into or out of it. Unfortunately, the gradient based purely on diffusion is limited to a symmetrical parabolic profile and has an attainable maximum diameter of ~ 20 mm (in the case of a radial gradient refractive lens), with most commercial forms having a diameter of 2 mm. It has been found difficult to introduce larger and slower diffusing species.

Some attempts have been made to form single-composition glasses through additive manufacturing. A single composition of silica glass has been produced through lamination molding using selective laser melting (SLM), in which silica particles are melted and fused in a silica powder bed. In addition, glass of a single composition has been produced through a laminate molding process (G3DP) in which silica is melted in a high-temperature vessel similar to a kiln and the melted glass ribbon is laminated through a nozzle. In this way, a selectively melted region is obtained which is vulnerable to thermally induced stresses during filament or cooling, so that an undesired refractive index gradient is formed across the thickness of the component, for example, thereby preventing the part from achieving optical quality . Moreover, the selectively molten region may also result in resistance to coalescence of the segments by leaving trapped pores between the segments. In addition, this method is not amenable to strictly controlled introduction of various compositions. It would be desirable to be able to print and construct the structure without high temperature.

Various embodiments described herein use direct ink writing (DIW) laminate formulations to introduce a composition gradient into an amorphous low density form (LDF). After complete formation, the LDF is heat treated to become transparent as an entire structure, thus reducing the edge effect.

Current methods of forming a glass of gradient composition have also proved difficult. In a slurry-based 3D printing (S-3DP) system, after the LDF is built up and dried from the slurry, a dopant is added. Such a process requires structural integrity in the LDF. In addition, the introduction of a dopant in a low-viscosity droplet onto a dried object may cause the chemical species of interest to diffuse radially and axially and fill the pores of the underlying dried structure through capillary forces, Control over the composition gradient can be difficult. The composition gradient can also be limited to materials (e.g. small molecules, ions) that can be easily incorporated into the LDF by diffusion. Thus, it would be desirable to develop a process to form a glass of gradient composition during formation of the LDF and prior to drying of the LDF, wherein the dopant is a component of the mixture.

The various embodiments described herein may be used to (1) form optical or non-optical glasses with a custom composition profile that is not achievable by conventional glass processing techniques, (2) And (3) the formation of glass optics with customized patterned material properties much larger than can be achieved by the diffusion method.

Some embodiments described herein achieve a desired compositional change by introducing a gradient through the DIW laminate molding and using continuous in-line mixing of the free-forming species, with or without dopants. LDF is completely formed before drying. The dopant itself can be ions, molecules and / or particles and can premix with free-forming species in a high viscosity suspension, thereby limiting its diffusion in LDF at low temperatures.

In accordance with one embodiment, the method includes forming a structure by printing an ink comprising a glass-forming material, and heat treating the formed structure to convert the glass-forming material to glass.

According to another embodiment, the product comprises a monolithic glass structure having the physical characteristics of formation by three-dimensional printing of an ink comprising a glass-forming material. Other aspects and advantages of the present invention will become apparent from the following detailed description, which illustrates the principles of the invention in connection with the drawings.

1 is a flow diagram of a method for manufacturing a glass member having a user-tailored composition profile, according to one embodiment.
2A is a schematic diagram of a method for manufacturing a single composition glass member, according to one embodiment.
Figure 2B is a schematic diagram of a method for manufacturing a multi-component glass member, according to one embodiment.
3A is an image of an extrusion of a glass-forming ink on a substrate, according to one embodiment.
Figure 3B is an image of a printed low density shaped body, according to one embodiment.
3C is an image of a glass shaped body after heat treatment of a printed low density shaped body, according to one embodiment.
4A is a schematic diagram of a low-density shaped body including a material characteristic gradient of a low-density shaped body along an axial direction, according to one embodiment.
4B is a schematic diagram of a low density shaped body comprising a material property gradient of a low density compact along a radial direction, according to one embodiment.
5A is an image of a low-density shaped body having an axial gradient, after printing of a plurality of components, according to one embodiment.
FIG. 5B is an image of a glass shaped body having a gradient in the axial direction, after heat treatment of the printed low density shaped body, according to one embodiment.
Figure 5C is an image of a low density compact with a gradient in the radial direction after printing of a number of components, according to one embodiment.
4B is an image of a glass shaped body having a gradient in the radial direction after heat treatment of the printed low density shaped body, according to one embodiment.
6A-6C are images of a printed part formed to have a silica composition, according to one embodiment.
6D-6E are images of a printed part formed to have a silica-titania composition, according to one embodiment.
7A is a plot of refractive index profile versus titania concentration of glass formed according to one embodiment.
Figure 7B is an image of the resulting glass structures formed to have various titania concentrations, according to one embodiment.
8 is a plot of the heat treatment profile of the formation of a consolidated structure according to one embodiment. The images of each step are included as inserts on the profile plot.
9A is an image of a gradient refractive silica-titania glass lens manufactured by direct ink recording, according to one embodiment.
Figure 9B is a surface-corrected interferogram of the glass lens of Figure 9A.
Figure 9C is an image of 300-μm focus from the lens of Figure 9A.
10A is an image of a composite glass comprised of a gold-doped silica glass core, according to one embodiment.
Figure 10B is a plot of absorbance as a function of wavelength of light of the composite glass of Figure 10A.
Figure 10C is a plot of the absorbance at 525 nm of the composite glass of Figure 10A versus the location along the glass surface.

The following description is intended to illustrate the general principles of the invention and is not intended to limit the inventive concepts claimed herein. In addition, certain features described herein may be used as each of various possible combinations and permutations with other features described.

Unless specifically defined otherwise herein, all terms are intended to include the broadest possible understanding of what is implied by the ordinary artisan in the art, and / or the meaning as defined in the dictionary, papers, etc., Interpretation.

It should also be noted that the singular forms " a, "and" the ", as used in the specification and the appended claims, include a plurality of referents unless the context clearly dictates otherwise.

The following description discloses various preferred embodiments of the manufacture of optical and non-optical glass members with a user-tailored composition profile and / or related systems and methods.

In one general embodiment, the method includes forming a structure by printing an ink comprising a glass-forming material, and heat treating the formed structure to convert the glass-forming material to glass.

In another general embodiment, the product comprises a monolithic glass structure having the physical characteristics of formation by three-dimensional printing of an ink comprising a glass-forming material.

A list of acronyms used in the description is provided below.

3D three-dimensional

DIW direct ink record

FDM Fusion Lamination Modeling

IR Infrared

G3DP glass three-dimensional printing

GRIN Gradient Index Glass

LDF low-density shaped body

Si silicon

S-3DP slurry-based three-dimensional printing

SLM selective laser melting

Ti titanium

UV UV

Various embodiments described herein provide a method for fabricating active or passive optical or non-optical glass elements and / or glass sensors with 1-, 2-, or 3-dimensional tailored material composition profiles. Various embodiments described herein enable three-dimensional (3D) printing of various inorganic glasses with or without compositional changes. Depending on the glass composition and processing conditions, the glass may look transparent or opaque to the human eye. However, the term "optical glass" refers not only to useful glasses in the visible light portion of the spectrum, but also to UV, visible light, near-IR, medium-IR and circular-IR.

1 shows a method 100 for manufacturing an optical glass member with a user-tailored composition profile according to one embodiment. Optionally, the method 100 may be implemented in an apparatus such as that shown in the other figures described herein. However, of course, such method 100 and others presented herein may be used to form a structure for a wide variety of devices and / or purposes that may or may not be associated with the exemplary embodiments enumerated herein. In addition, the methods presented herein can be carried out in any desired environment. Moreover, more or fewer operations than those shown in FIG. 1 may be included in the method 100, according to various embodiments. It should also be noted that any feature mentioned above may be used in any embodiment described in accordance with various methods.

In one embodiment as shown in FIG. 1, the method 100 begins with a job 102 that includes forming a structure by printing ink. According to various embodiments, printing of the ink may include one of the following laminate molding techniques which may have ink mixing capability: direct ink writing (DIW), stereolithography in a 3D system, projection micro-stereo lithography such as projection microstereolithography, fusion lamination modeling, electrophoretic laminating, PolyJet processing, direct lamination, inkjet printing, inkjet powder bed printing, aerosol jet printing, and the like. Combinations of these methods can also be considered.

In accordance with various embodiments, the method 100 can be used to form filaments, films, and / or 3D monolithic or spanning irregular-free-forms.

According to one embodiment, the ink comprises a glass-forming material. According to another embodiment, the glass-forming material comprises a prepared particle dispersion, wherein the particles are in the range of nanometers to micrometers in size. In some approaches, the particles can be monodispersed. In another approach, the particles can be multidispersed. In another approach, the particles can agglomerate.

In yet another embodiment, the free-forming material is selected from the group consisting of, for example, fumed silica, colloidal silica, LUDOX colloidal silica dispersion, titania particles, zirconia particles, alumina particles, metal chalcogenide particles For example, CdS, CdSe, ZnS, PbS), but is not limited thereto. In other embodiments, the free-forming material may be a monolithic inorganic-containing particle.

In one embodiment, the free-forming material can be, for example, a plurality of mixed composition particles, including, but not limited to, binary silica-titania particles, silica-germanium oxide particles, and / or inorganic or organic chemically modified surfaces (I.e., titania-modified silica particles; silica-modified titania particles; 3-aminopropyltriethoxysilane-modified silica particles).

In some embodiments, the glass-forming material may be a mixture of particles of different composition, for example, but not limited to, a mixture of silica particles and titania particles that are fused together to form a silica-titania glass.

According to one embodiment, the free-forming material may be a single-composition free-forming material that may not be in particulate form. In some embodiments, the dopant can be incorporated directly into the polymer, such as, but not limited to, silica, silica-titania containing polymer, silica-oxidized germanium polymer, silica-aluminum oxide polymer, silica-boron trioxide polymer, have.

According to some embodiments, the free-form material of the ink may comprise larger molecules and / or polymers (linear or branched) made from small metal-containing organic precursors. Examples of polymers include poly (dimethylsiloxane), silicon, diethoxysiloxane-ethyl titanate copolymers, polyhedral oligomeric silsesquioxane polymers and copolymers. Examples of large molecules include polyoxometallate clusters, oxoalkoxometallate clusters. Designer Si / Ti containing polymers can be obtained by acid-catalyzed hydrolysis of organosilicates and organotitanates, such as tetraethyl orthosilicate and titanium isopropoxide, and, if necessary, additional transesterification step Lt; / RTI > Modifications of this process include the use of organometallic chemical components containing a bond other than metal-oxygen, such as (3-aminopropyl) triethoxysilane; Doping the salt, for example NaF, Cu (NO ₃ ) ₂ , Li ₂ CO ₃ , directly by adding it to the polymer solution; Doping by incorporating metal species into the polymer chain during acid-catalyzed hydrolysis; Substitution of a main glass component (e.g. silicon (Si)) and a minor glass component (e.g. titanium (Ti)) with a linear polymerizable substituent such as Ge, Zr, V, Fe .

According to some embodiments, the free-form material of the ink may comprise a small metal-containing organic precursor and / or an inorganic precursor such as a metal alkoxide, siloxane, silicate, phosphate, chalcogenide, metal- have. Examples may include silicon alkoxides, boron alkoxides, titanium alkoxides, germanium alkoxides. In some approaches, the free-forming material of the ink may comprise titanium isopropoxide, titanium diisopropoxide bis (acetylacetonate), tetraethylorthosilicate, zinc chloride, titanium chloride.

In one embodiment, the free-formable material may be suspended in a solvent. In one embodiment in which the free-forming material is a polar and / or hydrophilic free-forming material, the solvent is preferably a polar aprotic solvent. In one approach, the solvent can be the following pure components or mixtures thereof: propylene carbonate, dimethyl ether (e.g., tetra (ethylene glycol) dimethyl ether), and / or dimethylformamide. In another approach, the solvent may be a polar protic solvent such as an alcohol and / or water. In one embodiment, where the free-forming material is hydrophobic, the solvent can be, but is not limited to, a non-polar solvent such as xylene, alkane.

According to one embodiment, the ink may be a combination of at least one second component and a glass-forming material that alters the properties of the heat-treated glass structure. In some embodiments, the second component may be a dopant that alters properties. In another embodiment, more than one material property may be affected by the addition of the second component. In various embodiments, the second component may affect the material properties (e.g., characteristics) of the resultant structure in terms of one or more of the following: optical, mechanical, magnetic, thermal, electrical,

In one approach, the second component may be in ionic form. In another approach, the second component may be a molecule. In another alternative approach, the second component may be a particle.

In some embodiments, the ink may contain an effective amount of one or more second components capable of altering the properties of the heat treated glass structure. The effective amount of the second component is an amount that alters the properties of the thermally treated glass structure, as will be apparent to one of ordinary skill in the art upon reading this disclosure and without undue experimentation, the concentration of the additive As shown in FIG.

In one embodiment, the color of the resulting structure can be influenced by the addition of one or more second components selected from the following classes: metal nanoparticles (gold, silver), sulfur, metal sulfides (cadmium sulfide) Metal chlorides (chloride), metal oxides (copper oxides, iron oxides).

In one embodiment, the absorbance (linear or nonlinear) of the resulting structure can be influenced by the addition of one or more second components selected from the following group: cerium oxide, iron, copper, chromium, silver, and gold.

In one embodiment, the refractive index of the resulting structure can be influenced by the addition of one or more second components selected from the following group: titanium, zirconium, aluminum, lead, thorium, barium.

In one embodiment, the dispersion of the resulting structure can be influenced by the addition of one or more second components selected from the following group: barium, thorium.

In one embodiment, the attenuation / optical density of the resulting structure can be influenced by the addition of one or more second components selected from the following group: alkali metals and alkaline earth metals.

In one embodiment, the sensitivity of the resulting structure can be influenced by the addition of one or more second components selected from the following groups: silver, cerium, fluorine.

In one embodiment, the electrical conductivity of the resulting structure can be influenced by the addition of one or more second components selected from the following group: alkali metal ions, fluorine, carbon nanotubes.

In one embodiment, the birefringence of the resulting structure, such as birefringence having a refractive index that depends on the direction of polarization and propagation of light imparted by the crystalline phase formed from the second component, is determined by the addition of one or more second components selected from the following group : Titanium, zirconium, zinc, niobium, strontium, lithium in combination with silicon and oxygen.

In one embodiment, the thermal conductivity of the resulting structure can be influenced by the addition of one or more second components selected from the following group: carbon nanotubes, metals.

In one embodiment, the thermal emissivity of the resulting structure can be influenced by the addition of one or more second components selected from the following group: tin oxide, iron.

In one embodiment, the thermal expansion coefficient of the resulting structure can be influenced by the addition of one or more second components selected from the following group: boron oxide, titanium oxide.

In one embodiment, the glass transition temperature of the resulting structure can be influenced by the addition of sodium carbonate as the second component.

In one embodiment, the melting point of the resulting structure may be influenced by the addition of one or more second components selected from the following group: sodium, aluminum, lead.

In one embodiment, the gain coefficient of the resulting structure can be influenced by the addition of one or more second components selected from the following group: rare earth ions (e.g. neodymium, erbium, ytterbium); Transition metal ions (e. G., Chromium).

In one embodiment, the light emission of the resulting structure may be affected by the addition of the second component. In another embodiment, the emission of the resulting structure can be influenced by the addition of the second component. In yet another embodiment, the fluorescence of the resulting structure can be influenced by the addition of the second component.

In one embodiment, the chemical reactivity of the resulting structure may be influenced by the addition of one or more second components selected from the following groups: alkali metals, alkaline earth metals, silver.

In one embodiment, the density of the resulting structure can be influenced by the addition of one or more second components selected from the following group: titanium, zirconium, aluminum, lead, thorium, barium.

In one embodiment, the concentration of the second component in the ink may vary during printing to form a composition gradient in the printed structure. In some approaches, the second component of the ink may form a compositional gradient in the heat-treated final structure.

In some embodiments, the concentration of the second component in the ink may form a compositional change (e.g., a gradient, pattern, etc.) that may not be symmetrical about any axis, for example, , Or the pattern may be formed as a complete 3D structure, or the like, but is not limited thereto.

In some embodiments, the ink may contain an effective amount of one or more additional additives to perform the specified function. For example, the additive can improve dispersion, phase stability, and / or network strength; control and / or change the pH; Modify rheology; Reduce crack formation during drying; May assist in sintering, or the like, but are not limited thereto. The effective amount of the additive is an amount that imparts the desired function or result, as will be apparent to one of ordinary skill in the art upon reading this disclosure and without undue experimentation, varying the concentration of the additive according to the teachings herein . ≪ / RTI >

In some embodiments, the ink may include one or more of the following additives to improve dispersion: a surfactant such as 2- [2- (2-methoxyethoxy) ethoxy] acetic acid (MEEAA) , Polyelectrolytes (e.g., polyacrylic acid), inorganic acids (e.g., citric acid, ascorbic acid).

In one embodiment, the ink may contain additives (e.g., boric anhydride (B ₂ O ₃ )) to improve phase stabilization (ie, to prevent phase / composition separation that may or may not be crystalline phase separation) . Another example is ZnO which can act as a phase stabilizer for alkali silicates.

In one embodiment, the ink may comprise an additive (e.g., boric anhydride B ₂ O ₃ ) to inhibit crystallization. Other crystallization inhibitors include Al ₂ O ₃ and Ga ₂ O ₃ .

In one embodiment, the ink may include an additive (e.g., polydimethylsiloxane) to enhance the network.

In one embodiment, the ink may include one or more of the following additives in order to control the pH: organic acid, inorganic acid or base (e.g. acetic acid, HCl, KOH, NH ₄ OH).

In one embodiment, the ink may comprise one or more of the following additives to modify the rheology: polymers (e. G., Cellulose, polyethylene glycol, polyvinyl alcohol); Surfactants (e. G., MEEAA, sodium dodecyl sulfate, glycerol, ethylene glycol); Metal alkoxides (e.g., titanium diisopropoxide bis (acetylacetonate)).

In one embodiment, the ink may include one or more of the following additives as drying adjuvants for enhancing crack resistance and / or reducing crack formation during drying: polymers (e. G., Polyethylene glycol, polyacrylates) Monomeric or polymeric and cross-linking reagents such as polyethylene glycol diacrylate (PEGDA).

In one embodiment, the ink may comprise an additive as a sintering aid. The sintering aids improve the sintering / densification process. In the case of glass, the sintering aid can sinter to lower the viscosity of the free material. For example, boric anhydride (B ₂ O ₃ ) may be included as a sintering aid.

In various embodiments, the blend of glass-forming ink (i. E., Glass-forming material) is optimized for a combination of the following factors: printability (depending on the 3D printing method), crack resistance, and sintering to transparency. . In some approaches, the volumetric loading of the combination of the glass-forming ink is optimized. In some approaches, the characteristics of the composition gradient of the free-forming material can be optimized.

According to one embodiment, the combination of free-forming materials comprises glass-forming inorganic species in the range of from about 5 vol% to about 50 vol% of the total volume; From about 30 vol% to about 95 vol%; The second component (s) (i.e. dopant) in the range of 0 wt% to about 20 wt%; And from 0 wt% to about 10 wt% of the additive (s).

EXAMPLE OF INK Combination 1

5-15 vol% fumed silica (Cabosil EH-5 or Carbosil OX-50)

30 to 95 vol% tetraethylene glycol dimethyl ether

0 to 20 wt% titanium diisopropoxide bis (acetylacetonate)

0 to 6 wt% ethylene glycol

0 to 2 wt% poly (dimethylsiloxane)

EXAMPLE OF INK Combination 2

75 to 95 vol% silica-titania-containing polymer

10 to 25 vol% tetraethylene glycol dimethyl ether

0 to 10 vol% H ₂ O for prehydrolysis

EXAMPLE OF INK Combination 3

5 to 20 vol% 25-nm titania-coated silica particles

25 to 45 vol% propylene carbonate

25 to 45 vol% tetraethylene glycol dimethyl ether

0 to 5 wt% MEEAA

According to one embodiment, the concentration of the second component in the ink may vary during printing to form a composition gradient in the structure, and thus the heat treated final structure.

In one embodiment, the temperature of the ink may be less than about 200 < 0 > C during printing.

In one embodiment, the method 100 comprises drying the formed structure to remove sacrificial material, wherein drying is performed prior to the heat treatment of the formed structure. Ideally, the fully formed structure is dried in a single process.

According to one embodiment as shown in FIG. 1, the method 100 includes an operation 104 that includes heat treating the formed structure to convert the glass-forming material to glass.

In one embodiment, the method comprises additional processing of the heat treated glass structure. In one approach, the method involves grinding the heat treated glass structure. In another approach, the method includes polishing the heat treated glass structure. In yet another alternative approach, the method includes grinding and polishing the heat treated glass structure.

In one embodiment, the heat treated glass structure may be in the form of fibers.

In another embodiment, the heat treated glass structure may be in sheet form.

In one embodiment, the heat treated glass structure may be a three dimensional monolith.

In another embodiment, the heat treated glass structure may be in the form of a coating on a substrate such as a part, tool, or the like.

2A and 2B illustrate a method 200 and 250 for fabricating an optical glass element with a user-tailored composition profile according to one embodiment. As an option, the methods 200 and 250 may be implemented in conjunction with features from any other embodiment listed herein, such as those described with respect to other figures. However, of course, such methods 200 and 250 and others presented herein may be used in various applications and / or permutations that may or may not be specifically described in the exemplary embodiments listed herein. Additionally, the methods 200 and 250 set forth herein may be used in any desired environment.

An exemplary embodiment of a method 200 for making a single component silica glass is shown in FIG. 2A. According to one embodiment, the method for printing ink includes DIW printing as shown in steps 222 and 224. DIW is a 3D printing process based on the extrusion of viscoelastic materials. The ink 202 is pushed out through the small nozzle 208 by the air pressure or the right side. In some approaches, the nozzle 208 is controlled by a computer and has three degrees of freedom (x, y, and z). In another approach, the nozzle 208 may be enlarged to have six axes for printing. The nozzles 208 may be arranged to extrude the ink into a controlled spatial pattern.

In steps 222 and 224, by the DIW, the filament 212 of the rheologically tuned glass-formed DIW ink 202, containing the free-forming species, is laminated to the predetermined geometry and weakly bonded A porous amorphous low density shaped body (LDF) 214 having a net-like shape is formed. In some approaches, the extruded filaments 212 rapidly solidify into LDF 214. [ In some approaches, the LDF 214 may be referred to as a green body, a glass-forming species, or the like. The free-forming species may be introduced as precursors and / or colloids / particles. In some approaches, the glass-forming DIW ink 202 may be a colloidal silica ink.

According to one embodiment, the blend of glass-forming DIW inks is optimized for printability, drying / bakeout, and sintering. Formulations of glass-forming DIW inks can be optimized for printability in terms of shear thinning, flow (rectification) capability, shape retention (shape retention) capability, low aggregation, long print times, stable pot life . Formulations of glass-forming DIW inks can be optimized for drying in terms of handling resistance, crack resistance, low / uniform shrinkage, porosity suitable for organic removal, and the like. Formulations of glass-forming DIW inks can be optimized for sintering in terms of crack resistance, low / uniform shrinkage, densification / transparency capability, low phase separation tendency, and the like.

In accordance with one embodiment, step 222 includes glass-forming DIW ink 202 extruded through a nozzle 208 that laminates filaments 212 as a single layer on a substrate 210.

Step 224 of method 200 includes forming a layer on the layer of glass-forming DIW ink 202 to form an LDF 214. 3A shows an image of a colloidal silica ink being extruded onto a substrate.

The LDF 214 can be processed through a number of steps to consolidate the LDF 214 and convert it to a heat treated glass shaped body 216

Optionally, the LDF 214 can be additionally machined to further change the composition of the part before or after drying. In some approaches, additional processing may include diffusion, leaching, etching, and the like. In another approach, the additional processing may include light, sound, vibration, or a combination thereof to alter the features of the printed form. In another approach, the chemical treatment before closing the pores of the LDF through heat treatment can limit the optical quality of the resulting glass shaped body as a result.

In step 226, the LDF can be treated by drying, calcining (i.e., removal of residual solvent / organic matter at elevated temperature), and the like. During drying, the liquid / solvent phase can be removed. The LDF 214 can be separated from the substrate 210 on which the LDF 214 is printed. In some approaches, the drying step 226 may include standing at temperatures below the boiling point of the solvent for hours to weeks.

In some embodiments, the processing step 226 may include a heating step at a lower temperature (i. E. Burnout) to remove any organic and any residual and / or adsorbed water / solvent phase. In some approaches, the incineration step may comprise standing at 250 to 600 DEG C for 0.5 to 24 hours.

In some embodiments, the processing step 226 may include heating the LDF 214 under an alternate gas atmosphere to chemically convert the surface (e.g., to convert the free surface hydroxyl to a dehydrated siloxane) have. In some approaches, the processing step 226 may include heating the LDF (214) under an oxidizing gas atmosphere (e.g., O ₂ gas). In another approach, processing step 226 may include heating the LDF 214 under a reducing gas atmosphere (e.g., H ₂ gas). In another approach, processing step 226 may include heating the LDF 214 under a non-reactive gas atmosphere (e.g., Ar, He). In another approach, processing step 226 may include heating the LDF 214 under a reactive gas atmosphere (e.g., N ₂ , Cl ₂ ). In another approach, processing step 226 may include heating the LDF 214 under vacuum.

In some embodiments, the machining step 226 may also include making a dense compact by compressing the part of the LDF 214 (i. E., By reducing porosity) using uniaxial or isostatic pressure. In some approaches, the processing step 226 may also include compressing the components of the LDF 214 under vacuum (i.e., reducing the porosity).

Figure 3B shows an image of the dried LDF.

According to one embodiment, the method includes heat treating the dried LDF 214, as shown in step 228 of FIG. 2A, to close the remaining pores to form a consolidated clear glass part. In some approaches, dense shaped bodies of LDF can be heat treated.

The heat treatment step 228 may include sintering to make the LDF 214 (i. E., The glass-forming inorganic species) fully densified at elevated temperature to a solidified solid glass shaped body 216. In some approaches, the sintering of the LDF can include standing at 500 to 1600 占 폚 for several minutes to several hours. The temperature for sintering depends on the material composition and the initial inorganic load and the porosity of the LDF. In some approaches, the sintering of the LDF may involve the simultaneous use of applied pressure. In some approaches, the heat treatment step 228 may be performed at various atmospheric conditions. In another approach, heat treatment step 228 may be performed under vacuum.

In some embodiments, the heat-treated glass shaped body 216 may be a monolithic glass structure. Fig. 3C shows an image of the monolithic glass structure after the heat treatment of the LDF shown in Fig. 3B. Fig. In some embodiments, the resulting solidified glass shaped body 216 may retain the characteristics of the ink 202 that may have been imparted during DIW printing (steps 222, 224).

In one embodiment, the consolidated glass shaped body 216 has a physical characteristic of the LDF 214, including helical, arcuate and / or straight ridges present along one surface of the glass shaped body 216 .

In one embodiment, the glass shaped body 216 may be post-processed in a post-machining step 230 to provide the desired optical properties of the final optical shaped body 218 polished through techniques such as, for example, grinding and / Appearance and / or surface finish can be achieved. In one embodiment, the polished optical body 218 is a polished shaped body by 3D printing and heat treatment, so the characteristics of the LDF 214 are maintained and are not lost by polishing. In one embodiment, the polished optical body 218 is a polished monolithic glass structure.

In some approaches, the glass shaped body 216 may be treated as bolted glass, thereby allowing any traces of the printing process to be removed by conventional techniques known in the pertinent art. In another approach, the glass shaped body 216 retains properties that can only be achieved by the printing process described herein after post-processing.

According to one embodiment, a schematic depiction of a method 250 for forming a gradient and / or spatial pattern on a glass product is shown in FIG. 2B. In other embodiments, compositional changes (e.g., gradients, patterns, etc.) that may not be symmetrical with respect to any axis may be made by the method, for example, Or the pattern may be formed as a complete 3D structure or the like, but is not limited thereto.

In one approach, a gradient index (GRIN) glass can be formed by the above method. Printing of GRIN glass involves printing monoliths that have no pores, wherein the formation of LDF characterizes the void filling, high aspect ratio, and favorable modulus / viscosity as revealed by spanning. The method may also include matching the rheology of the two DIW inks required to form the gradient. In some embodiments, two, three, four, etc. of the inks may be combined via mixing before the filaments are extruded onto the substrate.

According to one embodiment, during the DIW printing step 232, 234, the filament composition 213 can be adjusted during printing by adjusting the flow rate of the individual streams to introduce the desired compositional change in the desired area in the LDF 214 have.

In some approaches, different inks 203 and 204 may be separately introduced to form the LDF 215. 4A, in one approach, a monolithic glass structure 400 (LDF 215 of FIG. 2B) having the physical characteristics of formation by 3D printing is formed in a monolithic glass structure < RTI ID = 0.0 > Type glass structure 400 along the axial direction of the glass substrate 400. The direction of the axis 408 is perpendicular to the lamination plane 410.

2B, the glass structure is formed as an LDF (LDF 215 of FIG. 2B), which may be the second glass-forming ink 204 after the first glass-forming ink 203 has been extruded. do. The resulting glass structure 400 in Figure 4A has a first glass 403 and a second glass 404 from a first glass-forming ink 203 and a second glass-forming ink 204, respectively.

4A, the resultant glass structure 400 is formed between a first glass 403 formed from a glass-forming material and a second glass 404 formed from a second glass-forming material having a composition different from the glass-forming material (Not shown). In some approaches, the first glass 403 and the second glass 404 may not intermix because the second glass-forming material may not migrate across the interface to the first glass-forming material, or vice versa Because.

In one embodiment, the interface 406 is oriented substantially along the lamination plane 410 of the monolithic glass structure 400 to form a monolithic glass structure having two portions of a first glass 403 ) And the second glass 404, respectively.

As shown in Figures 5A-5D, silica with two different inks of silica and silica with 20 nm gold nanoparticles was used to form a composition change that resulted in a change in material properties in the final heat treated structure. Figures 5A and 5B show forming an axial phase in the absorption in the heat treated final structure. As shown in FIG. 5A, the LDF was formed to have a texture change, wherein a first ink silica was used to form a portion of the LDF (bottom of the LDF in FIG. 5A), followed by a second ink, silica / Gold nanoparticle ink (top of LDF in Figure 5A). The LDF was then sintered at the heat treatment (step 238 of FIG. 2B) and solidified to be free. A resultant, monolithic glass structure with an absorbance gradient along the axial direction is shown in Figure 5B, wherein the silica / gold nanoparticle portion of the glass is on top in Figure 5B.

In one embodiment, the physical characteristics of the monolithic glass structure 217 include a gradient comprising two or more glass-forming materials to make the interface between the first and second glass-forming materials uniform . As shown in FIG. 5A, there is an interface between the upper glass-forming material (silica / gold nanoparticles) and the lower material (silica). Further, the first glass-forming material (silica) does not migrate to the second glass-forming material (silica / gold nanoparticle), while the second glass-forming material (silica / gold nanoparticle) Silica).

Using the prior art methods for 3D printing optical glass, the embodiments described herein could not be achieved because prior art methods have made it difficult to control thermal gradients during 3D printing and / or the interface between filaments is uneven And / or can not incorporate a large number of substances into the raw body or the LDF.

In another approach, a smooth compositional change can be formed by blending the ink stream from different inks 203, 204 in-line through active mixing using mixing paddles 206 near the tips of nozzles 208 . As shown in the schematic depiction of the top view of Figure 4B, in one approach, the monolithic glass structure 420 (LDF 215 of Figure 2B) having the physical characteristics of formation by 3D printing has a refractive index, G., Absorbance, may be included along the radial direction of the monolithic glass structure 420. < RTI ID = 0.0 > The radial direction 412 direction exists in any direction along the lamination plane 410. Referring again to Fig. 2B, the glass structure is formed as an LDF (LDF 215 in Fig. 2B) with a radial refractive index step, where in Fig. 2B the two inks 203 and 204 are blended inline as an ink stream. The resulting glass structure 420 in Figure 4B has a first glass 414 and a second glass 413 from the first glass-forming ink 203 and the second glass-forming ink 204, respectively.

4B, the resultant glass structure 420 is formed between a first glass 414 formed from a glass-forming material and a second glass 413 formed from a second glass-forming material having a composition different from the glass-forming material Gt; 416 < / RTI > In some approaches, the first glass 414 and the second glass 413 may not mix together because the second glass-forming material may not migrate across the interface to the first glass-forming material, or vice versa Because.

In one embodiment, the interface 416 is oriented substantially perpendicular to the lamination plane 410 of the monolithic glass structure 420 so that the monolithic glass structure 420 can be aligned with the two The first glass 413 and the second glass 414, which are portions of the first glass 413 and the second glass 414, respectively.

According to one embodiment, tissue changes in LDF can be printed using two different inks, resulting in a material property of a radially absorbance step in the heat-treated final structure. As shown in Figs. 5C and 5D, the radial absorbance step was printed using silica / gold nanoparticles, the first ink being silica and the second ink, wherein the two inks were blended inline as an ink stream. 5C shows an LDF shaped body having a silica / gold nanoparticle ink in the center of the LDF and a silica ink in the outer portion of the LDF. The resulting monolithic glass structure with an absorbance gradient along the radial direction is shown in Figure 5D.

The compositional change may not be limited to axial and / or radial gradients (such as may be achieved by diffusion techniques), but rather it may be used to form any profile in the LDF.

The compositional change in the LDF 215 may result in various material properties in the formed glass 217. [ Examples of material properties that can be influenced by compositional changes in the LDF 215 are described in more detail above and may include, but are not limited to: absorptivity, transmittance, refractive index, Dispersion, scattering, electrical conductivity, thermal conductivity, thermal expansion coefficient, gain coefficient, glass transition temperature (Tg) melting point, light emission, fluorescence, chemical reactivity (eg etching rate), density / porosity.

As shown in FIG. 2B, according to one embodiment, the DIW printing at steps 232, 234 may comprise forming an LDF 215. The LDF starts as a single layer on the substrate 210 in a first step 232 of DIW printing. As the DIW printing continues in step 234, the LDF 215 can be formed one by one until the desired LDF 215 (i.e., the raw body) is formed.

In some embodiments, the formation of LDF with a single composition (method 200) or the formation of LDF with multiple compositions (e.g., a gradient) (method 250) may include fusion laminate modeling (FDM) . FDM uses thermoplastic filaments (see steps 232-234 of FIG. 2B), which can be a complex mixture of different materials combined using mixing paddles, similar to the DIW ink mixture. The resulting filaments may be extruded through heated nozzles to form an LDF on the substrate as shown in step 222-224 or steps 232-234 of Figures 2A and 2B, respectively. The heated nozzle partially heats the filament for extrusion at a temperature in the range of about 150 ° C to 200 ° C. In some approaches, the sacrificial support material may be extruded using a second nozzle to provide a support for the glass-forming material being extruded by the mixing nozzle. In some approaches, the polymer and / or support material of the extruded filaments can be removed after formation of the LDF.

In various embodiments, the LDF can be formed into a complex shape, such as, but not limited to, conical, corkscrew, cylindrical, and the like.

The LDF 215 can be processed in a number of steps in order to consolidate the LDF 215 and convert it into a heat-treated glass shaped body 217.

Once the LDF 215 is formed, the LDF 215 can be dried and / or additionally machined, as described above for step 226 of the method 200 in FIG. 2A.

Referring again to FIG. 2B, according to one embodiment, step 238 of method 250 includes heat treating the dried LDF 215 to close the remaining pores and form a consolidated clear glass part. The resulting solidified glass shaped body 217 may retain compositional variations that may have been imparted during DIW printing (steps 232, 234).

In one embodiment, the consolidated glass form 217 may have the physical characteristics of the LDF 215, including spiral, arcuate, and / or linear bends that exist along a surface of the glass shaped body 217.

According to one embodiment, the glass shaped body 217 may be further processed in a post-machining step 240 to provide a desired finish of the final optical body 220 polished, for example via a technique such as grinding and / Appearance and / or surface finish can be achieved. In one embodiment, the polished optical body 220 is a polished shaped body by 3D printing and heat treatment, so the characteristics of the LDF 215 are maintained and are not lost by polishing. In one embodiment, the polished optical body 220 is a polished monolithic glass structure.

The various embodiments described herein can be applied to a wide variety of substrates, including silica-based glass, phosphate-based glass, borate glass, germanium oxide glass, fluoride glass, aluminosilicate glass, and chalcogenide glass, ) It can be extended to amorphous inorganic organic materials.

Heat treatment Example 1

Printed monolithic silica or untreated silica-titania (25 mm diameter, 5 mm thick) is placed on a 100 占 폚 hot-plate. After 3 hours, the printed green body is separated from the substrate. The green body is then dried in a box furnace at 100 DEG C for 110 hours. Subsequently, the green body containing no liquid is heated to 600 占 폚 at a heating rate of 10 占 폚 / min and left for 1 hour to incinerate the remaining organic components. The green body is then heated from 100 占 폚 / hr to 1000 占 폚 and held under vacuum for 1 hour. Finally, the components are sintered in a preheated furnace at 1500 ° C for 3 to 10 minutes. The parts are then recovered and quickly cooled to room temperature. All non-vacuum processing steps are performed in air.

Heat treatment Example 2

The printed monolithic silica untreated body, consisting of 25-nm diameter silica or silica-titania particles (25 mm diameter, 5 mm thickness) is heated in a box furnace at 3 ° C / h to 75 ° C. When the oven reaches 75 캜, the printed green body is separated from the substrate. The green body is then dried in a drying oven at 75 DEG C for 120 hours. Subsequently, the green body containing no liquid is heated to 600 DEG C at a heating rate of 1 DEG C / minute and left standing for 1 hour to incinerate the remaining organic components. Finally, the components are sintered at 1150 ° C for 1 hour in a preheated furnace. The parts are then recovered and quickly cooled to room temperature. All non-vacuum processing steps are performed in air.

Experiment

6A-6F are images of a printed part made of ink formulation 3 (as described above). Figures 6A-6C are images of printed parts formed to have a silica sole composition. 6A is an image of a green body formed after printing. 6B is an image after drying of the green body of Fig. 6A. Fig. Fig. 6C is an image after solidification of the dried green body of Fig. 6B. Fig.

6D-6F are images of a printed part formed to have a silica-titania composition. 6D is an image of a green body formed after printing. 6E is an image after drying of the green body of Fig. 6D. Fig. Figure 6F is an image after cementing of the dried green body of Figure 6E.

Figure 7A is a plot of the refractive index profile (y- axis) versus glass of titania (TiO ₂₎ concentration (wt%, x- axis) as a result. The glass made from Ink Formulation 1 (as described above) is shown on the plot as diamond (solid line) and is comparable to commercial silica (▲) and silica-titanate glass (○, □) Refractive index variation. Figure 7B shows the diamond () of Figure 7A at various wt% concentrations of TiO ₂ (2 wt%, 4 wt%, 5 wt%, 6 wt%, 8 wt%, 9 wt%, 10 wt% Is an image of the resultant glass structure formed from the resulting ink formulation.

Figure 8 is a plot of the heat treatment profile of the process of forming consolidated, printed parts using ink formulation 1 (as described above). During the heat treatment process, the volume contraction of the structure at each step (V _ink ) is shown next to the image of the structure.

9A is a gradient refractive index of the silica prepared by the direct recording ink LDF during blending the two inks to the print heads in line ratio required to laminate the radial gradient of the TiO ₂ concentration - an optical image of a titania glass lens. Was (described above) are two ink in from the ink formulation 1 using the ink A was contained 0% titanium alkoxide ink B is sufficient titanium alkoxy to result in 1.6 wt% TiO ₂ in the anti-caking final glass Respectively. The glass was cured using the heat treatment profile shown in Figure 8 and then polished using a ceria pad polishing. Figure 9B is a surface-corrected interferogram showing how the refractive index changes in the mass of material seen in the image of Figure 9A. The refractive index is the highest at the center of the TiO ₂ composition and lowest at the edge with the lowest TiO ₂ concentration. The line crossing the center shows a change in the refractive index across the center as shown by the embedding plots of Fig. 9B (y-axis is 隆 n / (n ₀ -1) and x-axis is distance (mm) , Which suggests that the part can function as a lens. Figure 9C is an image of a 300-μm focus from a lens with a focal length of 62 cm.

10A is an optical image of a composite glass consisting of a gold-doped silica glass core and an undoped silica glass cladding made by direct ink-writing of the composition change to the LDF. Two silica inks were used, one of which contained gold nanoparticles. FIG. 10B is a plot of absorbance as a function of wavelength of light, where each spectrum corresponds to the position indicated throughout the glass. The peak at 525 nm was due to the absorbance from gold nanoparticles. Figure 10C is a plot of the absorbance (y-axis) at 525 nm versus the location along the glass surface (x-axis, where position 0 is the center of the glass). The plot of Figure 10C shows that the absorbance at 525 nm was adjusted in these glasses. The measured spot size exceeded the mean ~ 1 mm diameter spot.

Usage

The various embodiments described herein may be applied to active or passive optical glass elements (e.g., lenses, corrector plates, windows, screens, collectors, etc.) having specialized composition and material properties for both commercial and governmental applications A waveguide, a mirror blank, a sensor, etc.). These methods can be used to determine the degree of absorption, transmittance, refractive index, dispersion, scattering, electrical conductivity, thermal conductivity, thermal expansion coefficient, gain coefficient, glass transition temperature (Tg), melting point, light emission, fluorescence, (Or tailored) region within a glass member (monolith, film, or atypical-shaped body) to achieve a spatially diverse material properties including glass transition temperature, density, Can be used.

The various embodiments described herein provide a method for making complex 3D and controlled color glass artwork, ornaments, and the like. Control of the dopants of silver and gold nanoparticles allows control of the reflection and transmission characteristics of the artwork.

Additional embodiments include non-optical glass members useful in conventional applications as well as active or passive optical glass members useful for lenses, calibration plates, windows, screens, collectors, waveguides, mirror blanks, sensors and the like.

The inventive concepts disclosed herein have been presented to illustrate numerous features in a number of exemplary scenarios, embodiments, and / or implementations. It should be appreciated that in general the concepts disclosed should be regarded as modular and may be implemented as any combination, permutation, or combination thereof. Also, any modifications, alterations, or equivalents of the features, functions, and concepts disclosed herein, which are known to those of ordinary skill in the art upon reading this description, should also be considered to fall within the scope of this disclosure.

While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Accordingly, the breadth and scope of embodiments of the present invention should not be limited by any of the exemplary embodiments described above, but should be limited only by the following claims and their equivalents.

Claims (21)

Forming a structure by printing an ink comprising a glass-forming material;
Heat treatment of the formed structure to convert the glass-forming material to glass
≪ / RTI > The method of claim 1, comprising drying the formed structure to remove sacrificial material, wherein drying is performed prior to the heat treatment of the formed structure. The method of claim 1, wherein the ink is a combination of a second component and a glass-forming material that alters the properties of the heat treated structure. 4. The method of claim 3, wherein the concentration of the second component in the ink is varied during printing to form a composition gradient in the structure. The method of claim 1, wherein the temperature of the ink is less than about 200 占 폚 during printing. The method of claim 1, wherein the free-forming material is selected from the group consisting of silica, fumed silica, colloidal silica, LUDOX colloidal silica dispersion, titania particles, zirconia particles, alumina particles, and metal chalcogenide particles ≪ / RTI > The method of claim 1, wherein the glass-forming material is suspended in a solvent during formation. 2. The method of claim 1 including at least one of grinding and polishing of the heat treated structure. The method of claim 1 wherein the heat treated structure is in fibrous form. The method of claim 1, wherein the heat treated structure is in sheet form. The method of claim 1, wherein the heat treated structure is in a three-dimensional monolith form. The method of claim 1, wherein the heat treated structure is in the form of a coating on a substrate. The ink according to claim 1, wherein the ink is at least one of a dispersion improving property, a phase stability improving property, a network strength improving property, a pH control property, a pH changing property, a rutile modification property, And an effective amount of an additive that imparts one. A monolithic glass structure having the physical characteristics of formation by three-dimensional printing of an ink comprising a glass-
≪ / RTI > 15. The product of claim 14 wherein the physical feature of the formation by three-dimensional printing comprises a ridge present along one surface of the monolithic glass structure. The method of claim 14, wherein the monolithic glass structure is selected from the group consisting of 2- [2- (2-methoxyethoxy) ethoxy] acetic acid, polyelectrolyte, polyacrylic acid, inorganic acid, citric acid, ascorbic acid, boric anhydride, The organic acid or base, acetic acid, HCl, KOH, NH ₄ OH, cellulose, polyethylene glycol, polyvinyl alcohol, sodium dodecyl sulfate, glycerol, ethylene glycol, metal alkoxide, titanium di-isopropoxide bis (acetylacetonate ), A polymer, an additive selected from the group of polyethylene glycols, polyacrylates, crosslinkable monomers or polymers, and additives consisting of polyethylene glycol diacrylate. 15. The product of claim 14, wherein the physical feature of formation by three-dimensional printing comprises a refractive index gradient of a monolithic glass structure present along the axial direction of the monolithic glass structure. 15. The product of claim 14, wherein the physical features of formation by three-dimensional printing comprise a refractive index gradient present along the radial direction of the monolithic glass structure. 15. The method of claim 14, wherein the physical feature of formation by three-dimensional printing is that the difference between the first glass formed from the glass-forming material and the second glass formed from the second glass-forming material having a different composition from the glass- Wherein the first glass and the second glass are not intermixed with each other. 20. The product of claim 19, wherein the interface is oriented substantially along a plane of lamination of the monolithic glass structure, thereby dividing the monolithic glass structure into two portions having different compositions near the interface. 20. The product of claim 19, wherein the interface is oriented substantially perpendicular to the lamination plane of the monolithic glass structure, thereby dividing the monolithic glass structure into two portions having different compositions near the interface.

Images