Functional inorganics and ceramic additive manufacturing

CROSS REFERENCE TO RELATED APPLICATIONS

0001This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/065,324 filed Oct. 17, 2014, the entire contents of which are incorporated herein by reference thereto.

BACKGROUND

0003The present disclosure relates to additive manufacturing and, more particularly, to systems, methods and resins for additive manufacturing of ceramic phase structures.

0004Fabrication of ceramic parts for high-temperature applications using conventional methods is difficult. By way of example, some materials are difficult and expensive to machine due to hardness. Machining can require extended periods of time for dense materials. In addition, it may be especially challenging to use conventional methods to provide complex geometries and similarly to produce particular shapes.

0005There is a need for systems and methods of preparing components from dense material and similarly for producing components of high temperature applications.

BRIEF DESCRIPTION

0006Disclosed and claimed herein are systems, methods and resins for additive manufacturing of ceramic structures. One embodiment is directed to a method for additive manufacturing of a ceramic structure, the method including providing a resin, the resin including a preceramic polymer and inorganic ceramic filler particles dispersed in the preceramic polymer, wherein the preceramic polymer is configured to convert to a ceramic phase, and wherein the inorganic ceramic filler particles are functionalized with a reactive group and configured to convert to the ceramic phase. The method also includes applying an energy source to the resin to create at least one layer of the ceramic phase from the resin.

0007In one embodiment, the preceramic polymer is polycarbosilane.

0008In one embodiment, the ceramic phase is silicon carbide.

0009In one embodiment, the inorganic ceramic filler particles are functionalized with a reactive group.

0010In one embodiment, the energy source is a laser source for curing at least one of the preceramic polymer and ceramic filler particles.

0011In one embodiment, the resin is provided in a bath for additive manufacturing.

0012In one embodiment, the inorganic ceramic filler particles include functional groups configured to decompose and a ceramic phase, wherein the ceramic phase remains during fabrication.

0013In one embodiment, applying an energy source to the resin includes free form fabrication of a three-dimensional article formed of silicon carbide.

0014The method further includes processing an article formed by the layer and one or more additional layers by at least one of thermal, plasma, microwave and radiative curing, and curing methods in general.

0015Another embodiment is directed to a system for additive manufacturing of ceramics, the system including a bath configured to contain a resin, the resin including a preceramic polymer and inorganic ceramic filler particles dispersed in the preceramic polymer. The preceramic polymer is configured to convert to a ceramic phase, and the inorganic ceramic filler particles are functionalized with a reactive group and configured to convert to the ceramic phase. The system also includes an energy source proximate to the bath, and a controller coupled to the energy source and configured to apply the energy source to the resin to create at least one layer of the ceramic phase from the resin.

0016Another embodiment is directed to a resin for additive manufacturing of ceramics, the resin including a preceramic polymer wherein the preceramic polymer is configured to convert to a ceramic phase and inorganic ceramic filler particles dispersed in the preceramic polymer, wherein the inorganic ceramic filler particles are functionalized with a reactive group and configured to convert to the ceramic phase.

0017In one embodiment, the ceramic phase is silicon carbide

0018Other aspects, features, and techniques will be apparent to one skilled in the relevant art in view of the following detailed description of the embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

0019The features, objects, and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters identify correspondingly throughout and wherein:

0020<figref idref="DRAWINGS">FIG. 1</figref> depicts a simplified system diagram according to one or more embodiments;

0021<figref idref="DRAWINGS">FIG. 2</figref> depicts a graphical representation of particle functionalizing according to one or more embodiments;

0022<figref idref="DRAWINGS">FIG. 3</figref> depicts a process for additive manufacturing according to one or more embodiments; and

0023<figref idref="DRAWINGS">FIG. 4</figref> depicts a process for providing functionalizing particles according to one or more embodiments.

DETAILED DESCRIPTION

Overview and Terminology

0024One aspect of the disclosure relates to additive manufacturing, and in particular, to additive manufacturing using functionalized particles. One embodiment is directed to a resin including a preceramic polymer and functionalized particles. Other embodiments are directed to systems and methods for additive manufacturing with functionalized particles, such as functionalized inorganic particles. In an exemplary embodiment, silicon carbide (SiC) powder is functionalized (e.g., modified) such that the surface of the silicon carbide powder particles are functionalized with a chemical group that has the ability to convert to a non-oxide ceramic of choice and to interact selectively with an energy source. In that fashion, the functionalized surface of the particles can be cured or energized to react by laser light and thermally post processed to have a silicon carbide containing structure. Functionalization also includes adding a binding material to the powder. According to one embodiment, functionalization of the powder is a different step from buildup and curing of a structure.

0025In addition to functionalizing particles, another aspect is to provide a resin that will convert to a ceramic phase of choice.

0026As used herein, ceramic phase relates to a solid state and structure having homogeneous physical and chemical characteristics.

0027Preceramic polymer relates to a pre-cursor for the fabrication of silicon based ceramic.

0028Inorganic ceramic filler particles are particles or powders. The inorganic ceramic filler particles can be dry or in suspension with the resin.

0029Reactive group elements relate to surface components configured to provide binding of silicon based ceramic particles.

0030Photosensitive group elements relate to surface components configured to provide binding of silicon based ceramic particles and which are cured by a photo source.

0031As used herein, the terms “a” or “an” shall mean one or more than one. The term “plurality” shall mean two or more than two. The term “another” is defined as a second or more. The terms “including” and/or “having” are open ended (e.g., comprising). The term “or” as used herein is to be interpreted as inclusive or meaning any one or any combination. Therefore, “A, B or C” means “any of the following: A; B; C; A and B; A and C; B and C; A, B and C”. An exception to this definition will occur only when a combination of elements, functions, steps or acts are in some way inherently mutually exclusive.

0032Reference throughout this document to “one embodiment,” “certain embodiments,” “an embodiment,” or similar term means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of such phrases in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner on one or more embodiments without limitation.

Exemplary Embodiments

0033Referring now to the figures, <figref idref="DRAWINGS">FIG. 1</figref> depicts a simplified system diagram of system <b>100</b> according to one or more embodiments. System <b>100</b> may be configured for additive manufacturing of ceramics using a curable resin. By way of example, system <b>100</b> may employ functional inorganics to produce ceramics using a laser scanning process, such as stereolithography (SLA) or alternately using light emitting diodes (LEDS) or lasers in digital light processing (DLP). System <b>100</b> includes controller <b>105</b>, energy source <b>110</b>, platform <b>120</b>, and bath <b>125</b>.

0034Controller <b>105</b> is coupled to energy source <b>110</b> and configured to control application of the energy source <b>110</b> to the resin <b>130</b> to create at least one layer of the ceramic phase from the resin. Application of energy source <b>110</b> includes generation of laser, shown as energy source beam <b>115</b>, which may be employed to form a layer of the ceramic phase in order to generate three-dimensional structures. Energy source <b>110</b> may be a laser source for curing or reactively bonding at least one of the preceramic polymer and ceramic filler particles. Energy source <b>110</b> may be one or more of a light (e.g., photo), ultraviolet (UV), infrared (IR), e-beam source or other available regions of the electromagnetic spectrum. System <b>100</b> may include the use of multiple beams or more than one energy source. For example, in certain embodiments, system <b>100</b> may include one or more energy sources to provide different energies to interact with the resin. Energy source <b>110</b> may be positioned proximate to the bath <b>125</b> and resin <b>130</b>, such as above and/or near the resin <b>130</b>, for application of at least one of a beam and the source to resin <b>130</b>.

0035Platform <b>120</b> may be adjusted by elevator <b>140</b> to position one or more formed layers relative to energy source <b>110</b>. The position of platform <b>120</b> may be controlled by controller <b>105</b>.

0036Bath <b>125</b> is configured to contain and/or hold a resin <b>130</b>, such as a curable resin, including a preceramic polymer and inorganic ceramic filler particles dispersed in the preceramic polymer. In one embodiment, the ceramic filler particles are functionalized with a photosensitive group. In another embodiment, the preceramic resin is functionalized with a reactive group. According to another embodiment, catalysts can be used to enhance the curing or reactivity of the functional group. Resin <b>130</b> is provided in a bath <b>125</b> for additive manufacturing. In one embodiment, resin <b>130</b> is a liquid suspension. According to another embodiment, resin <b>130</b> is a slurry of inorganics. Resin <b>130</b> can include inorganic ceramic filler particles that include functional groups configured to decompose and a ceramic phase, wherein the ceramic phase remains during fabrication of the three-dimensional structure. According to another embodiment, resin <b>130</b> is a nanofluid.

0037In one embodiment, system <b>100</b> is configured to build three dimensional ceramic structures, such as silicon carbide structures. As such, the preceramic and ceramic phase may be selected to generate silicon carbide. To that end, in one embodiment, the preceramic polymer is polycarbosilane and the ceramic phase is silicon carbide. The resin <b>130</b> may be configured at a molecular level to convert to a ceramic phase, or other phase of choice, such as ceramic phases suitable for high temperature applications. For example, to create a silicon carbide part, system <b>100</b> can employ a preceramic polymer that thermally converts to silicon carbide, such as a polycarbosilane or modified polycarbosilane. In one embodiment, resin <b>130</b> would be slurry filled with ceramic filler particles that are uniformly dispersed in the resin <b>130</b>. By way of example, a silicon carbide particle is chemically functionalized with a reactive group, such as a photo-sensitive group that can also convert to a desirable ceramic phase such as SiC. The functionalized SiC particles would be created in slurry form and energy source <b>110</b>, which may be a laser-based SLA-type system, is configured to cure the slurry layer-by-layer so that a three dimensional solid would be constructed. Upon removal of unsolidified resin or slurry, the ‘green ceramic body’ could be further post-processed by exposure to one or more of thermal, plasma, microwave, and other radiative methods.

0038When excited by energy source <b>110</b> and energy source beam <b>115</b>, the polycarbosilane component of resin, such as resin <b>130</b>, may form an amorphous, partially crystalline or crystalline structure of silicon carbide. Application of energy source <b>110</b> to the resin <b>130</b> includes free form fabrication of a three-dimensional article formed of silicon carbide. In one embodiment, application of laser beam <b>115</b> to resin <b>130</b>, and in particular resin surface <b>135</b>, at least partially converts the preceramic polymer and ceramic filler particles to a ceramic phase, such as silicon carbide.

0039According to one embodiment, structures formed by system <b>100</b> may be further processed by at least one of thermal, plasma, microwave and radiative exposure, and curing methods in general.

0040Although the discussion of system <b>100</b> refers to silicon carbide, it should be appreciated that other inorganics and ceramic polymers may be employed by the system for additive manufacturing.

0041System <b>100</b> may be configured to build and fabrication dense, monolithic ceramic parts for high temperature turbine applications. System <b>100</b> may additionally allow for fabrication of complex geometries from hard and brittle materials by additive manufacturing. In addition, system <b>100</b> may allow for direct fabrication of engineering ceramics using resin-based additive manufacturing methods including direct fabrication of engineering ceramics useful for turbine components.

0042<figref idref="DRAWINGS">FIG. 2</figref> depicts a graphical representation of particle functionalizing according to one or more embodiments. According to one embodiment, inorganic particles may be functionalized prior to addition to a resin (e.g., resin <b>130</b>). <figref idref="DRAWINGS">FIG. 2</figref> depicts an inorganic particle <b>205</b>, which may be silicon carbide. Particle <b>205</b> and additional inorganic particles are functionalized shown as <b>210</b>, with reactive group elements, such as photosensitive group elements shown as <b>211</b>. Functionalized particle <b>215</b> is shown including particle <b>205</b> and a plurality of photosensitive group elements <b>211</b>. Functionalized particles may be distributed and dispersed in a preceramic polymer, such as a polycarbosilane liquid. Functionalized particle <b>215</b> may be a functionalized inorganic particle. According to one embodiment, the extent and composition of functionality can be tailored. In certain embodiments, functionalized particle <b>215</b> may be formed of functional groups that intentionally decompose to leave behind desirable ceramic phases, such as silicon carbide.

0043According to one or more embodiments, exemplary reactive group elements for functionalizing may include one or more of silyl, halo, haloformyl, hydroxyl, alkyl, alkenyl, alkynl, carboxamido, carbonyl, oxo, amino, azo, benzyl, amido, carboxyl, cyanato, imino, keto, nitro, peroxy, phenyl, phosphate, phosphoro, sulfonyl and sulfo, as well as short chain structures containing one or more such functional groups. According to one or more embodiments, exemplary photosensitive group elements include aryl azides, halogenated aryl azides, azoquinones, cinnamoyl groups, benzophenones and, anthroquinones. According to one or more other embodiments, particles, such as particle <b>205</b>, may be between 100 nanometers and 250 microns in average diameter. In other embodiments, particles, such as particle <b>205</b>, may be between 200 nanometers and 100 microns in average diameter. In yet another embodiment, particles, such as particle <b>205</b>, may be between 500 nanometers and 50 microns in average diameter. Particle size distributions particle <b>205</b> can be mono-, bi- or multi-modal. According to one embodiment, functionalization of particles, such as particle <b>205</b>, converts relatively unreactive, benign surface of the starting particle to that of a reactive, convertible surface. According to one embodiment, the functionalized particle <b>215</b> may be cured or reacted together, shown by <b>225</b> to form a layer <b>230</b>. Layer <b>230</b> may be a cured network layer of functionalized silicon carbide ceramic particles, as would be found in a single build layer of a 3-D volumetric build. Functional groups are bonded to other functional groups or particles and may have partially converted to ceramic phase(s).

0044One or more additional layers may be formed to layer <b>230</b> for additive manufacturing or buildup, shown as <b>235</b> to form a three-dimensional object <b>240</b>. Build up <b>235</b> may be an iterative build up of layers via stereolithography or digital light processing. Three-dimensional object <b>240</b> represents a silicon carbide ceramic structure from functionalized particle <b>215</b> and resin (e.g., resin <b>130</b>). Three-dimensional object <b>240</b> may be post processed and/or machined following a build process.

0045According to one embodiment, inorganic particles may be functionalized and dispersed in a resin for additive manufacturing. <figref idref="DRAWINGS">FIG. 2</figref> depicts silicon carbide as an exemplary inorganic particle. However, it should be appreciated that one or more other types of particles may be employed, including but not limited to oxides, non-oxides, carbides, nitrides, oxycarbides, oxynitrides, borides, phosphides, etc. Although the description of <figref idref="DRAWINGS">FIG. 2</figref> relates to silicon carbide, the systems and methods described herein may employ exemplary inorganics such as one or more of SiC, Si₃N₄, B₄C, SiCN, SiOC, HfC, AlN, BN, ZrO₂, SiO₂, Hf<b>0</b>₂, Al₂O₃, B₂O₃, yttrium silicate and disilicate, and the like, and may relate to mixtures thereof.

0046<figref idref="DRAWINGS">FIG. 3</figref> depicts a process for additive manufacturing according to one or more embodiments. Process <b>300</b> may be initiated at block <b>305</b> with providing a resin (e.g., resin <b>130</b>) with functionalized particles (e.g., functionalized particle <b>215</b>). The resin is provided to include a preceramic polymer and inorganic ceramic filler particles dispersed in the preceramic polymer. The preceramic polymer is configured to convert to a ceramic phase, such as silicon carbide. In one embodiment, the preceramic polymer of <figref idref="DRAWINGS">FIG. 3</figref> is polycarbosilane. Polycarbosilanes and modified polycarbosilanes may be characterized as having a structural backbone including silicon-carbon and can produce silicon carbide on pyrolysis or controlled decomposition. Similarly, polysiloxanes may be characterized by a silicon-oxygen backbone and produce silicon oxycarbides on pyrolysis.

0047The inorganic ceramic filler particles are functionalized with a reactive group, such as inorganic ceramic filler particles <b>215</b> and configured to convert to the ceramic phase. The inorganic ceramic filler particles include functional groups configured to decompose and a ceramic phase, wherein the ceramic phase remains during fabrication. In one embodiment, the functionalized particles are uniformly dispersed in the resin. The resin may be provided in a bath for additive manufacturing.

0048At block <b>310</b>, one or more layers may be formed/built by applying an energy source to the resin to create at least one layer of the ceramic phase from the resin. Applying an energy source to the resin includes free form fabrication of a three-dimensional article formed of silicon carbide. The energy source may be a laser source for curing at least one of the preceramic polymer and ceramic filler particles. By way of example, a “green body” may be formed at block <b>310</b>.

0049For example, if silicon carbide is the desired ceramic phase, polycarbosilane may be employed as the preceramic polymer. Polycarbosilane is a liquid polymer with silicon carbon binding, the addition of heat will convert the polymer to silicon carbide with extensive shrinkage, but ultimately can produce amorphous, partially crystalline or fully crystalline silicon carbide. According to one embodiment, a resin or resin slurry can be provided by combining a preceramic polymer and functionalizing of silicon carbide powder. One layer of the resin or resin slurry may be provided with a laser or energy beam of an energy source to draw the structure of choice. Another layer of resin would then be provided, followed by repeated exposure to an energy source. In this manner, a three-dimensional structure containing resin, which may be partially converted to ceramic, and functionalized silicon carbide filler would be constructed. This structure then has the ability to be processed by heat later on to create more silicon carbon structure. Thus, silicon carbide powder in a matrix of silicon carbide are created by the polymer. The polymer, which may be cured resin plus silicon carbide filler, is part of the build up.

0050At block <b>315</b>, the formed structure may be cured or reacted. Curing or reaction may include heating and/or applying pressure to a formed article. Curing or reaction may include exposing a formed article to a particular atmosphere composition. As a result of the curing, articles may be hardened and/or shrink.

0051Process <b>300</b> may optionally include post-processing of the formed structure at block <b>320</b>. Processing at block <b>320</b> may include one or more of the an article formed by the layer and one or more additional layers by at least one of thermal, plasma, microwave, exposure to another electromagnetic energy source, and radiative curing, and curing methods in general. Anything not cured could be removed. In addition, post processing of the article with heat would create more silicon carbide from the structure. After heat treating, articles may be post processed by importing more resin into any voids of the 3D structure.

0052<figref idref="DRAWINGS">FIG. 4</figref> depicts a process for providing functionalized particles according to one or more embodiments. According to one embodiment, a resin is based on curable preceramic polymer, wherein the resin is curable by one or more of a light (e.g., photo), UV, IR, e-beam or other energy source. Process <b>400</b> depicts a process for providing a resin. In one embodiment, process <b>400</b> is initiated at block <b>405</b> with receiving inorganic particles, such as an inorganic powder. Process <b>400</b> includes bonding reactive group elements to the inorganic particles at block <b>410</b>. For example, inorganic ceramic filler particles are functionalized at block <b>410</b> with a photosensitive group. The reactive group elements and/or the inorganic ceramic filler particles are configured to convert to the ceramic phase, such as silicon carbide.

0053Functionalizing allows for a binder to be introduced with inorganic particles. With respect to silicon carbide powder, the particles will have silicon carbon bonding. According to one embodiment, another silicon containing species, such as silane-based coupling agent, may be chemically bonded to the silicon carbide powder. The bonding functionalizes the surface of the particles including a reactive or photoactive functional group, which in turn produces a modified powder. The powder can be dispersed into a fluid that is either reactive, photochemically sensitive, or also contains that ability to convert to silicon carbide. Although the discussion herein may refer to silicon carbide, other pre-ceramic polymer materials may be employed. Resins and other preceramic polymers may be chosen to make silicon carbide, silicon nitride, silicon carbide nitride, and silicon oxy-carbide as the primary resins. In certain embodiments, derivatives of the polymers may be modified with boron or aluminum to provide additional properties. Functionalization of the powder is a different step than buildup and curing. In addition to functionalizing the material, resin is selected to convert to a ceramic of choice.

0054Process <b>400</b> may optionally include suspending the functionalized inorganic particles in the resin at block <b>415</b>. Suspension of the functionalized particles at block <b>415</b> may include uniform distribution of the particles into a preceramic polymer that is configured to convert to a ceramic phase, such as polycarbosilane.

0055While this disclosure has been particularly shown and described with references to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the claimed embodiments.