Sintering system and sintered articles

Abstract

A method of forming a sintered tape material comprising grains of inorganic material comprises placing a leading section of the tape on a conveyor material such that a first major surface of tape in the leading section directly contacts a portion of the conveyor material. The method also comprises moving the leading section through a heating station by moving the portion of the conveyor material through the heating station in a downstream direction, wherein the leading section is in frictional engagement with the portion of the conveyor material. The method also comprises heating at least a portion of the tape within the heating station to a temperature above 500°C such that the inorganic material of the tape is sintered as it moves through the heating station, wherein the portion of the conveyor material that moves through the heating station is disposed both upstream and downstream of the heating station.

Description

SINTERING SYSTEM AND SINTERED ARTICLESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority of U.S. Application Serial No. 63 / 668,451, filed on July 08, 2024, the content of which is relied upon and incorporated herin by reference in its entirety.BACKGROUND

[0002] The disclosure relates generally to methods for sintering, such as sintering green tape including polycrystalline ceramic grains or other inorganic particles, bound in a binder, as well as continuous and discrete sintered articles, such as ceramic sheets, tapes or ceramic pieces made from such methods. The disclosure relates articles, such as thin sheets, tapes, ribbons or pieces of ceramic or other inorganic materials that have many potential uses, such as serving as waveguides, when the ceramic is transmissive to light, serving as substrates that may be coated or laminated, and integrated in batteries and other components, or used as or joined with a substrate such as to act as a dielectric in an electronics package (e.g., LED package), or other applications.SUMMARY

[0003] An aspect (1) of the present disclosure relates to a method of forming a sintered tape material comprising grains of inorganic material, the method comprising: placing a leading section of the tape on a conveyor material such that a first major surface of tape in the leading section directly contacts a portion of the conveyor material; moving the leading section through a heating station by moving the portion of the conveyor material through the heating station in a downstream direction, wherein the leading section is in frictional engagement with the portion of the conveyor material; and heating at least a portion of the tape within the heating station to a temperature above 500°C such that the inorganic material of the tape is sintered as it moves through the heating station, wherein the portion of the conveyor material that moves through the heating station is disposed both upstream and downstream of the heating station.

[0004] An aspect (2) of the present disclosure pertains to a method according to the aspect (1), further comprising unwinding the tape from an input reel disposed upstream of the heating station, wherein some of the tape is still wound around the input reel when theleading section is placed on the portion of the conveyor material, wherein the unwinding of the tape from the input reel occurs at a first feed rate in the downstream direction that is greater than a rate at which the conveyor material is moved through the heating station to compensate for shrinkage of the tape within the heating station.

[0005] An aspect (3) of the present disclosure pertains to a method according to the aspect(2), wherein the tape is connected to the input reel while the inorganic material of the tape is sintered.

[0006] An aspect (4) of the present disclosure pertains to a method according to the aspect(3), further comprising attaching the leading section with an output reel disposed downstream of the heating station and rotating the output reel as the inorganic material is sintered to form a roll of the sintered tape material.

[0007] An aspect (5) of the present disclosure pertains to a method according to the aspect(4), wherein the conveyor material is a sheet of material that extends through the heating station between a conveyor unwind roller disposed upstream of the heating station and a conveyor wind roller disposed downstream of the heating station.

[0008] An aspect (6) of the present disclosure pertains to a method according to the aspect(5), wherein moving the portion of the conveyor material comprises rotating the conveyor unwind roller and the conveyor wind roller.

[0009] An aspect (7) of the present disclosure pertains to a method according to the aspect(6), further comprising, once the leading section is attached to the output reel, rotating the input reel and the output reel to feed the tape through the heating station at a second feed rate to at least partially sinter the grains to one another within the heating station.

[0010] An aspect (8) of the present disclosure pertains to a method according to the aspect(7), wherein the conveyor material is stopped once the leading section is attached to the output real such that, during sintering of the remainder of the tape, the remainder of the tape is dragged over the conveyor material.

[0011] An aspect (9) of the present disclosure pertains to a method according to the aspect (7), further comprising, when the sintering station operates to at least partially sinter the grains to one another in a steady state, the conveyor wind roller and the conveyor unwind roller are rotated to move the conveyor material in the heating station.

[0012] An aspect (10) of the present disclosure pertains to a method according to the aspect (9), wherein, while the sintering station operates in the steady state, the conveyor unwind roller and conveyor wind roller are rotated to advance the conveyor material in the downstream direction at a rate that is less than the second feed rate so that shrinkage of the tape during sintering is compensated.

[0013] An aspect (11) of the present disclosure pertains to a method according to the aspect (9), wherein, while the sintering station operates in the steady state, the conveyor unwind roller and conveyor wind roller are rotated to either: (a) advance the conveyor material in the downstream direction at a rate that varies from that at which the tape travels through the heating station to place the tape under tension; or (b) move the conveyor material in the upstream direction.

[0014] An aspect (12) of the present disclosure pertains to a method according to any of the aspects (7)-(l 1), wherein, as the conveyor wind roller rotates, segments of the conveyor material that contact the tape are rolled into the conveyer wind roller and replaced by new segments of the conveyor material that have not previously contacted the tape.

[0015] An aspect (13) of the present disclosure pertains to a method according to any of the aspects (l)-(2), wherein the tape comprises a plurality of discrete sections of tape material and the leading section comprise an entirety of each of the plurality of discrete sections of tape material.

[0016] An aspect (14) of the present disclosure pertains to a method according to the aspect (13), wherein the placing the leading section of the tape on the conveyor material comprises placing the plurality of discrete sections of tape material onto the conveyor material upstream of the heating station as a plurality of discrete green bodies.

[0017] An aspect (15) of the present disclosure pertains to a method according to the aspect (13), wherein the plurality of discrete sections of tape material are cut from a ribbon of partially sintered tape material.

[0018] An aspect (16) of the present disclosure pertains to an article formed by the method according to any of aspects ( 1 )-( 15), the article comprising a body comprising ceramic grains sintered to one another, wherein the grains comprise lithium, wherein greater than 95% of the body by weight consists of cubic lithium garnet crystals, wherein the body comprises: a plurality of pores such that the body exhibits a total porosity of less than or equal to 10%, a thickness, measured between first and second major surfaces of the body, that is in a rangefrom 3 pm to 50 pm, a width, measured in a first direction perpendicular to the thickness, of 5 mm or greater, a length, measured in a second direction perpendicular to the first direction, 5 cm or greater, and an average grain size of 5 pm or less.

[0019] An aspect (17) of the present disclosure pertains to an article according to the aspect (16), wherein the grains do not comprise lanthanum zirconate.

[0020] An aspect (18) of the present disclosure pertains to an article according to any of the aspects ( 16)-( 17), wherein the body has a length of at least 5 m.

[0021] An aspect (19) of the present disclosure pertains to a system for sintering a tape comprising grains of inorganic material, the system comprising: a heating station comprising an entrance, an exit, and a channel extending between the entrance and the exit; a conveyor unwind roller disposed upstream of the entrance; a conveyor wind roller disposed downstream of the exit; and conveyor material extending through the channel between the conveyor unwind roller and the conveyor wind roller, wherein: the conveyor material is attached to both the conveyor unwind roller and conveyor wind roller, the conveyor unwind roller and conveyer wind roller are rotatable such that a segment of the conveyor material that is disposed within the channel is alterable in either an upstream direction or a downstream direction, and the conveyor material is configured to directly contact the tape when a segment of the tape is disposed within the channel to sinter the grains.

[0022] An aspect (20) of the present disclosure pertains to a system according to the aspect(19), further comprising: an input reel from which the tape is unwound upstream of the heating station; and an output reel that receives the tape downstream of the heating station after the tape is sintered, wherein the tape continuously extends from the input reel to the output reel and is in direct contact with the conveyor material within the channel.

[0023] An aspect (21) of the present disclosure pertains to a system according to the aspect(20), wherein the conveyor unwind roller and the conveyor wind roller are configured to rotate so that the conveyor material does not slide relative to the tape as the tape is conveyed through the channel.

[0024] An aspect (22) of the present disclosure pertains to a system according to the aspect (20), wherein the conveyor unwind roller and the conveyor wind roller are configured to stop movement of the conveyor material within the channel so that the tape can be dragged over the conveyor material.

[0025] An aspect (23) of the present disclosure pertains to a system according to the aspect (20), wherein the conveyor unwind roller and the conveyor wind roller are configured to rotate to advance the conveyor material through the channel at a different rate than a rate at which the tape is fed through the channel to apply tension to the tape.

[0026] An aspect (24) of the present disclosure pertains to a system according to any of the aspects (19)-(23), wherein a sintered end of the tape is attached to the uptake reel via a jumper film adhered thereto.

[0027] Additional features and advantages will be set forth in the detailed description that follows, and, in part, will be readily apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings.

[0028] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understand the nature and character of the claims.

[0029] The accompanying drawings are included to provide a further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and the operation of the various embodiments.BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:

[0031] FIG. 1 schematically depicts a system for producing a sintered article, according to one or more embodiments of the present disclosure;

[0032] FIG. 2 is a flow diagram of a method for producing a sintered article, according to one or more embodiments of the present disclosure;

[0033] FIG. 3 is a perspective view of an illustration of a portion of a sintered article, according to one or more embodiments of the present disclosure;

[0034] FIG. 4A is a perspective side view of a rolled sintered article, according to one or more embodiments of the present disclosure;

[0035] FIG. 4B is a cross-sectional view of the rolled sintered article of FIG. 4A, according to one or more embodiments of the present disclosure;

[0036] FIG. 5A depicts an example of placement of a section of a green tape on a conveyor material and movement of the section through a heating station via the conveyor material, according to one or more embodiments of the present disclosure;

[0037] FIG. 5B depicts an example of the attachment of a sintered end of the tape shown in FIG. 5A to an output reel via a jumper fdm, according to one or more embodiments of the present disclosure;

[0038] FIG. 5C depicts an example of an onset of winding the tape around the output reel shown in FIG. 5B, according to one or more embodiments of the present disclosure;

[0039] FIG. 5D depicts an example of steady state winding of the tape around the output reel shown in FIG. 5B to form a rolled sintered article according to one or more embodiments of the present disclosure;

[0040] FIG. 5E depicts the tape depicted in FIG. 5C and 5D just downstream of an exit of the heating station shown in FIG. 5D, according to one or more embodiments of the present disclosure;

[0041] FIG. 6A is an image of a side-perspective view of an example sintered article with a body comprising sintered grains of cubic lithium garnet crystals, according to one or more embodiments of the present disclosure;

[0042] FIG. 6B is an image of a polished cross-section of the example sintered article depicted in FIG. 6A, according to one or more embodiments of the present disclosure;

[0043] FIG. 7 is a PSD histogram for pores measured from separate segments of the example sintered article depicted in FIG. 6A, according to one or more embodiments of the present disclosure;

[0044] FIG. 8 is a SEM image of a major surface of the example sintered article depicted in FIG. 7A used for determining a grain size distribution, according to one or more embodiments of the present disclosure; and

[0045] FIG. 9 schematically depicts a sintering system for sintering a plurality of discrete bodies of material, according to one or more embodiments of the present disclosure.DETAILED DESCRIPTION

[0046] Referring generally to the figures, various embodiments of a system and method for manufacturing long, thin and / or wide sintered articles are shown and described, where by the term “sinter,” Applicant refers to the method of coalescing (e.g., directly bonding to one another) particles or grains (e.g., of a powdered or granular material) into a solid or porous body by heating the particles or grains without completely liquefying the particles or grains such that crystal structure of the particles or grains remain in the coalesced body, Particularly, the systems and methods described herein utilize a conveyor material that moves through a channel of a heating station in which grains of inorganic material of a tape are sintered together in the method of forming a sintered article. As described herein, in embodiments, the conveyor material continuously extends from a conveyor unwind roller disposed upstream of the heating station and a conveyor wind roller disposed downstream of the heating station. Unused conveyor material can be disposed around the conveyor unwind roller. The conveyor unwind roller and conveyor wind roller can be rotatable to replace the segment of conveyor material that contacts the tape in the heating station. By replacing the conveyor material in the heating station with unused conveyor material, the conveyor system facilitates the removal of degraded conveyor material and enables waste ribbon product to be removed from the heating station. This way, the sintering system does not have to be shut down when the product ribbon breaks, as broken pieces can be efficiently moved by movement of the conveyor material. It is believed that this will facilitate method uniformity (e.g., to produce sintered articles having consistent surface quality).

[0047] A particularly beneficial aspect of the conveyor system described herein is that it provides a new way to start a continuous sintering process for forming relatively long sintered articles from an input roll of green tape wound on a spool or reel (herein referred to as an “input reel”). As explained in more detail below, the green tape material includes grains of inorganic material (e.g., such as grains of ceramic material, grains of poly crystalline ceramic material, metal grains or grains of synthetic material) bound with an organic binder material. The green tape is guided through the heating station where the organic binder material is removed and the grains are sintered to one another to form a sintered tape. Downstream of the heating station, the sintered tape is taken up into an uptake reel (or “output reel”). Certain existing reel-to-reel sintering methods require the use of a leader material to thread the tape between the input reel and the output reel. Such leader-based methods involve bonding of the leader material to an end of the green tape upstream of theheating station and coupling the leader material to the uptake reel, which can rotate to pull the end of the green tape through the heating station. Such leader-based methods have been found to be incompatible with certain grains of inorganic material that are reactive with common leader materials. Moreover, the method of routing the leader material through the heating station and binding the leader material to the green tape can be time consuming and lead to inefficiencies. The conveyor system described herein eliminates these issues associated with such leader-based methods by providing a way to move a section of tape from a green end of the system (upstream of the heating station) to a fired end of the system (downstream of the heating station) without that section being attached to any components outside of the heating station. An end of the green tape can be placed on the conveyor material, the conveyor material can be moved through the heating station, and frictional engagement between the conveyor material and tape results in the end being moved through the heating station for attachment to the output reel, after which the system can be operated to fully sinter the tape as the tape is moved from the green end to the sintered end via rotation of the input and output reels. The conveyor system described herein eliminates the need to bond any leader materials to the green tape and does not require routing leader through the heating station, thereby eliminating time consuming process steps.

[0048] The conveyor system described herein also provides alternative ways of applying tension to the tape to control the tape’s shape. Tensioning the tape has been found to mitigate warpage of the tape to facilitate fabricating relatively thin and flat sintered articles, as described in greater detail herein. Certain existing systems utilize one or more rollers disposed on the green end of the heating station to tension the tape. In embodiments of the present disclosure, the rotation of one or both of the conveyor unwind roller and the conveyor wind roller can be controlled to apply tension to various portions of the tape. For example, in embodiments, as the tape is moved through the heating station in the downstream direction via rotation of the input reel and the output reel, the conveyor unwind rollers can be rotated at a rotational rate faster than that associated with the tape, slower than that associated with the tape, or in the upstream direction. As such, the conveyor can be used to apply tension to the ribbon along the entire length of the heating station rather than only applying tension outside of the heating station as in certain existing methods. It is believed that such tensioning can improve thickness uniformity and flatness of the sintered articles over those produced with existing methods.

[0049] Furthermore, by eliminating the need for a continuous connection between the green and fired ends of the sintering system, the conveyor system described herein enables the sintering system to be used to produce sintered articles not in the form of continuous tape. Separate green bodies can be placed on the conveyor material and sintered to form batches of sintered bodies. Additionally, stacks of such separate green bodies could be formed, with pieces of conveyor material separating adjacent green bodies in the stack. Such a stacked arrangement could be used to increase process throughput. Such separate bodies could be cut from a continuous green body (e.g., from an input reel) or prepared in a discrete forming method. Alternatively or additionally, the conveyor system can be used to fully sinter bisque segments of partially cured green bodies and / or to perform post-sintering heat treatments on fully sintered segments.

[0050] The conveyor system described herein therefore adds flexibility to sintering systems used to fabricate long, continuous sintered articles by providing an additional method for method initiation, adding an additional tensioning mechanism via the adjustable speed of the conveyor unwind and conveyor wind rollers, facilitating the sintering of non-continuous, discrete articles, and providing compatibility with certain inorganic materials that tend to react with commercially available leader materials.

[0051] As used herein, the term “tape” is used to describe a segment of material having a width far exceeding its thickness (e.g., by least 20 times). The tape can either be in the form of a plurality of discrete segments of tape material or single segment of long, continuous tape material having a length far exceeding the width (e.g., by at least 20 times). When referring to a long, continuous piece of tape material, the “tape” can be attached to both an input reel and an output reel, with a portion extending through a heating station of a sintering system, and, in such cases, term “tape” is used herein to refer to the entire body of material extending from the input reel to the output reel. The tape can include a green tape portion that is upstream of the heating station, and a sintered tape portion that is disposed downstream of the heating station.

[0052] Referring to FIG. 1, a system 10 for producing a sintered article is shown, according to an exemplary embodiment. In general, green tape material is provided to system 10 at an input side 12, and the green tape material moves through system 10 generally in a downstream direction 11. At the input side 12, a source continuous tape material 18 (‘continuous’ meaning long lengths, as disclosed herein, such as 300 cm or longer, which can be provided in the form of a spool or belt) is provided, and is fed to the downstream portionsof system 10. As shown, the continuous tape material 18 is a tape that extends from the input side 12 of the system 10 (upstream of a heating station 34) to an output side 14 (downstream of the heating station 34) of the system 10. Herein, the terms “continuous tape material 18” and “tape 18” are used interchangeably.

[0053] In general, continuous tape material 18 includes a layer of green tape material 20 that includes grains of inorganic, sinterable material bound together with an organic binder (e.g., (e.g., polypropylene carbonate, polyvinyl butyral, dibutyl phthalate, polyalkyl carbonate, acrylic polymers, polyesters, silicones, etc.). The green tape material 20 of the continuous tape material 18 is or may be supported on a carrier web or backing layer (not depicted). As will be discussed in more detail below, in specific embodiments, system 10 is configured to form long, wide and / or thin sintered articles and in such embodiments, the green tape material 20 coming into the system 10 is also relatively long, wide and / or thin. For example, in specific embodiments, green tape material 20 has a width greater than 5 mm, greater than 10 mm, greater than 40 mm or greater than 125 mm. In specific embodiments, green tape material 20 has a length greater than 5 meters (m), specifically greater than 10 m, greater than 20 m and more specifically greater than 60 m. In specific embodiments, green tape material 20 has a thickness between 3 microns and 1 millimeter. In addition, incoming green tape material 20 has a porosity that is greater than the porosity of the sintered article produced by system 10. In other contemplated embodiments, the green tape material 20 may have a width less than 5 mm, such as at least 0.5 mm, at least 1 mm, at least 2.5 mm, or smaller than 0.5 mm in some such embodiments. Similarly, the tape may have another thickness and / or length and / or porosity. In some embodiments, the green tape material 20 may have a non- rectangular cross-section orthogonal to its length, such as round, oblong, parallelogram, rhomboid, etc., where, as may be intuitive, width of such embodiments refers to a maximum cross-sectional dimension orthogonal to length and thickness is a minimum cross-sectional dimension orthogonal to length.

[0054] In general, the green tape material 20 is a relatively delicate structure that is pulled through system 10 via the operation of various spools, reels, rollers, etc. The pulling action imparts a tension the green tape material 20. As shown, the system 10 includes a tension roller 32 around which the green tape material 20 is routed and pulled to place the green tape material 20 into tension. In embodiments, a relatively low level of tension (e.g., gram levels; 0. 1 grams to less than 1 kg; at least 1 gram, at least 5 grams, and / or no more than 100 grams, depending upon the tape size and binder strength) is applied to the green tape material 20 atthe tension roller 32 to improves various characteristics, such as cross-width shape and flatness of the final sintered article. However, due to the delicate nature of the green tape material 20 (which becomes even more delicate following binder removal as described in more detail below), the low level of tension is precisely controlled such that enough tension is provided to green tape material 20 to limit distortion during binder removal / sintering of green tape material 20 while also limiting maximum tension to ensure green tape material 20 does not break. With that said, in other contemplated embodiments, greater tension, such as for stronger tapes, or zero tension, other than tension due to weight of the tape itself, is applied.

[0055] After tensioning, the green tape material 20 moves in the downstream direction 11 to a heating station 34 for binder removal and sintering. The heating station 34 comprises an entrance 35, an exit 37, and a channel 104 extending between the entrance 35 and the exit 37. In embodiments, the channel 104 is defined by one or more tubes of a suitable material (e.g., alumina) extending between the entrance 35 and the exit 37. The channel 104 can have any suitable shape. In embodiments, for example, the channel 104 is defined in part by a horizontal, and an upper surface 120 which defines at least a portion of the lower surface of channel 104. The upper surface 120 can support the tape 18 as it traverses the channel 104 and therefore at least partially determine the shape of the tape 18 during sintering and debinding. In more specific embodiments, the upper surface 120 can be a flat, planar surface extending parallel to the downstream direction 11, and parallel to surfaces of input and output reels of the input and output systems 12 and 14, as described herein.

[0056] While depicted as a single component, it should be understood that, in embodiments, the heating station 34 can include two substations: a binder removal station and a sintering station disposed downstream of the binder removal station. In general, the binder removal station includes one or more heating elements that deliver heat the channel 104. Heat within binder removal station chemically changes and / or removes at least a portion of the organic binder material of the green tape material 20, such that unbound tape exits binder removal station and advances to the sintering station. The unbound tape includes the grains of inorganic material with very little or no organic binder remaining. In embodiments, the binder removal station comprises an active heater (e.g., an electric heating element, a gas heating element, a microwave heating element, a laser, or a combination thereof) that heats the green tape material 20 to bum the organic binder therein. The binder removal station can include a plurality of zones (e.g., two zones, three zones, four zones, five zones, six sones, oran even greater number of zones arranged successively in the downstream direction 11) so that the rate at which the temperature of a particular portion of the green tape material 20 changes can be controlled as it traverses the binder removal station. According to an exemplary embodiment, temperatures experienced by the green tape material 20 in the binder removal station may be at least 50°C, such as at least 100°C, at least 200 °C, at least 250 °C, and / or below a sintering temperature for the inorganic grains carried by the green tape material 20, such as less than 1200 °C, such as less than 900 °C, or less than 600°C.

[0057] In embodiments, the sintering station of the heating station 34 includes one or more heating elements (see, e.g., further discussion of heating elements and types thereof below) that heats sintering station 38 to temperatures above 700°C (e.g., between 700 °C and 3200°C) which causes sintering of the grains of inorganic material of unbound tape. In general, the porosity of the inorganic material decreases during sintering. This decrease in porosity may also result in a shrinkage (e.g., a reduction in width, thickness, length, etc.) of the tape material as the material is sintered. With some materials, during sintering, the elastic modulus can increase, the strength can increase, the shape of the porosity can change, without a significant decreasing in porosity or significant shrinkage. In some embodiments, the sintering station transforms the tape 18 into a bisque material that is partially, but not fully sintered. The sintering station can include a plurality of zones (e.g., two zones, three zones, four zones, five zones, six sones, or an even greater number of zones arranged successively in the downstream direction 11) so that the rate at which the temperature of a particular portion of the green tape material 20 changes can be controlled as it traverses the sintering station. Such control of a time-dependent temperature profile to which a particular portion of the tape 18 is exposed during de-binding and sintering can reduce stresses in the material, which can reduce deformation and improve flatness and uniformity of the sintered articles described herein. Relatively steep temperature gradients in the heating station 34 can be avoided to prevent such stresses.

[0058] In embodiments, the heating station 34 blows and / or draws gas over and / or under (e.g., over and under) the green tape material 20 as the green tape material 20 advances through the binder removal station and sintering station. For example, the heating station 34 may a flow of hot air into the channel 104 to communicate some or all of the heat energy to the green tape material 20, as may be delivered through an array of nozzles through a wall from a plenum, or through a porous wall material. In other embodiments, flow of the gas is facilitated by fans or pumps adjoining the channel 104. Tanks of pressurized gas may also beused as sources to supply gas to be blown over the tape. In some embodiments, the gas is air. In other embodiments, the gas is an inert gas, such as argon. The gas may aid in preventing the green tape material 20 from catching fire and may aid in heating the green tape material 20 without inducing thermal shock.

[0059] Following traversal of heating station 34, a partially or fully sintered tape material 40 enters the output side 14. Sintered tape material 40 is wound upon output reel 44. In the depicted embodiment, an interlayer support material 46 is paid off of a reel 48. Interlayer upport material 46 is wound unto output reel 44 such that a layer of interlayer support material 46 is or may be located between each layer or at least some layers of sintered tape material 40 on output reel 44. In general, interlayer support material 46 is a compliant, relatively high friction material that allows sintered tape material 40 to be held on to output reel 44 at a relatively low wind tension. The compliance of interlayer support material 46 can compensate for cross-web shape that may be present in the sintered tape material 40. The interlayer support material 46 also increases friction between adjacent layers of sintered tape material 40 on output reel 44 which limits sintered tape material 40 from sliding / telescoping of output reel 44. Applicant believes that without interlayer support material 46, sintered tape material 40 tends to slide off (e.g., telescope) of output reel 44 at least in part because the modulus of sintered tape material 40 is relatively high, limiting the ability of sintered tape material 40 to stretch under wind tension, which in turn tends to or may result in poor roll integrity.

[0060] In specific embodiments, system 10 is configured to produce sintered tape material 40 at a rate of at least 1 inch per minute, at least 5 inches per minute, at least 6 inches per minute, at least 8 inches per minute, at least 19 inches per minute, at least 29 inches per minute, and at least 59 inches per minute. For example, in embodiments, the system can be configured to produce sintered tape material 40 at a rate from 0.1 inches per minute to 60 inches per minute. In such embodiments, the tape 18 can have a width from 0.01 m to 1 m. For example, in specific embodiments, system 10 is configured to produce sintered tape material 40 from green tape 20 material having a width greater than 5 mm, 10 mm, 15 mm, 50 mm, or 100 mm.

[0061] The particular structure and arrangement of the input side 12, the output side 14, and the heating station 34 are not particularly limiting. Any suitable structure can be used. For more detail on potentially usable component structures for the input side 12, the output side14, and the heating station 34, refer to U.S. Patent No. 10,581,115, entitled “Electrolyte for a Solid-State Battery,” hereby incorporated by reference in its entirety.

[0062] Referring still to FIG. 1, the sintering system 10 further includes a conveyor system 50. The conveyor system 50 includes a conveyor unwind roller 52 disposed upstream of the entrance 35 of the heating station 34, a conveyor wind roller 54 disposed downstream of the exit 37 of the heating station 34, and conveyor material 56 extending through the channel 104 between the conveyor unwind roller 52 and the conveyor wind roller 54. The conveyor material 56 is attached to the conveyor unwind roller 52 and the conveyor wind roller 54 such that the portion of the conveyor material 56 extending between the conveyor unwind roller 52 and conveyor wind roller 54 can be placed in a state of tension by rotating at least one of the conveyor unwind roller 52 and the conveyor wind roller 54. As shown, in embodiments, the conveyor unwind roller 52 and the conveyor wind roller 54 are positioned such that the conveyor material 56 extends in a plane that is parallel (or within 3° of parallel) to that in which the upper surface 120 defining the channel 104 extends. The conveyor material 56 can be positioned in contact with the upper surface 120 so that, within the channel 104, the conveyor material 56 slides over the upper surface 120 to render the conveyor material 56 stable within the channel 104. Alternatively, the conveyor material 56 could be placed in tension so that the conveyor material 56 does not contact the upper surface 120.

[0063] The conveyor material 56 may be constructed of a suitable material based on the components of the tape 18, as the conveyor material 56 should be selected to be materially compatible (e.g., non-reactive) with the components of the tape 18. In embodiments, the conveyor material 56 is constructed of a graphite foil, which has relatively low thermal mass (e.g., to facilitate quick heating of the conveyor material 56 and avoid a temperature differential between the conveyor material 56 and the tape 18 as the tape 18 is conveyed through the channel 104). Graphite foil also has a sufficient static coefficient of friction with certain tape materials (e.g., formed from a green tape formed of LLZO grains and a PPC- based binder, as described herein with respect to the Example), such that frictional engagement between the tape 18 and the conveyor material 56 can be sufficient to pull the tape 18 through the channel 104 when an end of the tape 18 is not connected to the output reel 44, as described in greater detail herein. The graphite foil has also been found to have a dynamic coefficient of friction with respect to the tape 18 that is low enough, so that the tape 18 is able to slide with respect to the conveyor material 56 without imparting significant material damage to the tape 18. In preferred embodiments, it is desirable for the conveyormaterial 56 to have a thickness of less than or equal to 2.0 mm to facilitate winding of the conveyor material 56 around each of the conveyor unwind roller 52 and the conveyor wind roller 54.

[0064] As shown, the conveyor unwind roller 52 is rotatable about a first axis of rotation 58 and the conveyor wind roller 54 is rotatable about a second axis of rotation 60. In embodiments, one or more actuators (not depicted) are coupled to at least one of the conveyor unwind roller 52 and the conveyor wind roller 54 so that rotation rate and direction can be controlled (e.g., by a control unit). In embodiments, for example, the conveyor wind roller 54 and the conveyor unwind roller 52 can be rotated in unison such that the conveyor material 56 translates through the channel 104 at a controllable rate in the downstream direction 11 or in an upstream direction opposite the downstream direction 11.

[0065] Excess conveyor material can be wrapped around at least one of the conveyor unwind roller 52 and the conveyor wind roller 54. As the rollers rotate, the excess conveyor material can be provided into the channel 104 as the conveyor material 56. In a situation where excess conveyor material is wrapped around the conveyor unwind roller 52, for example, the conveyor unwind roller 52 can be configured such that, when the conveyor unwind roller 52 and the conveyor wind roller 54 are rotated in a clockwise direction to move the conveyor material 56 in the downstream direction 11, the excess conveyor material is unwound from the conveyor unwind roller 52, advanced through the channel 104, and wound around the conveyor wind roller 54. Excess conveyor material can also be wrapped around the conveyor wind roller 54 so that, when the conveyor unwind roller 52 and the conveyor wind roller 54 are rotated in a counterclockwise direction to move the conveyor material 56 in the upstream direction, the excess conveyor material is unwound from the conveyor wind roller 54, advanced through the channel 104, and wound around the conveyor unwind roller 52. Such excess conveyor material is beneficial in that the segments of conveyor material 56 placed within the channel 104 are adjustable. Once a particular segment of conveyor material 56 has been used for a predetermined time period or to make a certain length of sintered article (e.g., placed into contact with the tape 18), for example, the conveyor unwind roller 52 and conveyor wind roller 54 can be rotated so that an unused section of the conveyor material 56 (e.g., not yet placed in the channel 104) is used to interact with the tape 18. Such material cycling beneficially removes debris from the channel 104 and prevent damaged portions of the conveyor material 56 from producing defects on the sintered articles described herein.

[0066] As described herein, movement of the conveyor material 56 through the channel 104 can facilitate initiating the sintering process described herein without using any leader materials that are connected to the output reel 44. For example, a leading section of the green tape material 20 can be placed on the conveyor material 56 upstream of the entrance 35. The conveyor material 56 can then be advanced in the downstream direction 11 while the zones in the heating station 34 are operated to provide temperature profdes suitable for de-binding and at least partially sintering the leading section of green tape material 20. The conveyor material 56 is selected such that frictional engagement between the leading section and the conveyor material 56 is sufficient to advance the leading section through the channel 104 when the conveyor material 56 advances through the channel 104. Once the leading section is advanced downstream of the exit 37, the leading section is attached to the output reel 44 so that the tape 18 can be moved independent of the conveyor material 56 and the sintering method can be completed as in existing methods.

[0067] In embodiments, rotation of the conveyor unwind roller 52 and the conveyor wind roller 54 is controlled independently from the input reel 16 and output reel 44 so that the speed and direction at which the conveyor material 56 traverses the channel 104 can vary from that of the tape 18. For example, in embodiments, after the conveyor material 56 is used to initiate the sintering method, the conveyor material 56 can be stopped and the tape 18 can slide over the conveyor material 56 when the conveyor material 56 is stationary. Such a method enables tension in the ribbon to be controlled via the tension roller 32 in steady state sintering operation. In alternative embodiments, the conveyor material 56 can be conveyed at a rate corresponding to the rate at which the tape 18 traverses the channel 104 during steady state sintering so that the tape 18 does not slide relative to the tape 18 during sintering. This mode of operation may reduce any tension in the tape 18 resulting from friction between the tape 18 and the conveyor material 56.

[0068] In other alternative embodiments, the conveyor unwind roller 52 and the conveyor wind roller 54 can rotate such that the conveyor material 56 traverses the channel 104 in the downstream direction at a different rate than the tape 18. For example, the conveyor material 56 may traverse the channel 104 at a faster rate than the tape 18 or a slower rate than the tape. Such configurations are believed to be capable of applying tension along the entire length of the tape disposed in the channel 104, which is believed to potentially benefit the flatness of thickness uniformity of sintered articled fabricated via the system 10 over certain existing systems in which tension is created only at end points outside of the heating station 34.Another possible configuration is to move the conveyor material 56 in the upstream direction as the tape 18 is conveyed in the downstream direction 11 via the tension roller 32. In such a configuration, the conveyor material 56 could be moved at a slower rate through the channel 104 than the tape 18 is advanced in the downstream direction 11 to place the tape 18 under tension.

[0069] Referring now to FIG. 2, a flow diagram of a method 200 for fabricating a sintered article is shown, according to an example embodiment. The method 200 can be implemented via the system 10 described herein with respect to FIG. 1. Accordingly, reference to components depicted in FIG. 1 will be used to aid in the description of the method 200. It should be understood that the method 200 can be performed in systems other than the system 10 depicted in FIG. 1.

[0070] At block 204, a leading section of the green tape material 20 is placed on the conveyor material 56. For example the green tape material 20 may initially be entirely contained in the input reel 16 (e.g., wrapped around a spool thereof with a carrier web or backing layer disposed between adjacent layers of the green tape material 20). An end of the green tape material 20 may be routed around the tension roller 32 and the conveyor unwind roller 52, and then placed on the conveyor material 56 upstream of the entrance 35 of the heating station 34. In embodiments, the leading section may have a length of at least 12 inches along the downstream direction 11 to ensure sufficient friction between the conveyor material 56 and the green tape material 20.

[0071] At block 206, the leading section of the green tape material 20 is moved through the heating station 34 by moving the conveyor material 56 through the channel 104. As the conveyor material 56 is moved through the channel 104, the green tape material 20 may be fed in the downstream direction 11 by rotation of the input reel 16 and tension roller 32. The the input reel 16 is rotated so that the green tape material 20 is fed in the downstream direction 11 at a feed rate that is greater than the rate at which the conveyor material is moved through the channel 104 from the rotation of the conveyor unwind roller 52 and conveyor wind roller 54. In embodiments, the feed rate is greater to compensate for shrinkage of the tape 18 as it passes through the heating station 34. The feed rate of the green tape material 20 can be selected based on a modeled shrinkage of the tape 18 (e.g., determined based on the length of material extending through the channel 104, the composition of the tape 18, and the rate at which the conveyor material is moved) so that the end of the green tape material 20 does not move relative to the conveyor material 56 as the channel 104 is traversed. In otherwords, the feed rate of the green tape material 20 can be selected to minimize sliding of the tape 18 relative to the conveyor material 56 resulting from sintering-induced shrinkage.

[0072] At block 208, the green tape material 20 is heated in the heating station 34 such that grains of inorganic material therein are sintered to one another. As described herein, as the leading section is traversed through the heating station 34, the leading section may initial encounter a binder removal station to substantially remove organic binder material and then encounter a sintering station downstream of the binder removal station. Each of the binder removal station and the sintering station may comprise a plurality of independently controllable heating zones (with each zone containing one or more heating elements that are controllable based on a temperature detected in each zone) so that the temperature profile that the leading section encounters as a function of position within the channel 104 can be precisely controlled. In embodiments, the zones are controlled such that the leading section is exposed to temperatures ranging from 50°C to 600°C in the binder removal station and temperatures ranging from 800°C to 1700°C in the sintering station. For teachings with respect to potential temperature profiles usable in the binder removal and sintering stations, see U.S. Patent No. 10,581,115.

[0073] At block 210, the end of the sintered tape material 40 is attached to the output reel 44, which is rotated to take up the sintered tape material 40 in a spool such that the sintered tape material 40 continuously extends between the output reel 44 and the input reel 16. Once the leading section of the tape 18 traverses the channel 104 and is downstream of the exit 37, the end of the sintered tape material 40 can be attached to the output reel 44 using a jumper film (e.g., formed of a suitable polymeric material or other flexible film). A pressure sensitive adhesive can be used to bond the jumper film to both the sintered tape material 40 and the output reel 44. With the jumper film attached, the output reel 44 can be rotated until the tape 18 is placed in a state of slight tension to hold the tape 18 in a flat orientation to facilitate even sintering.

[0074] Once the sintered end is in the output reel 44 and the tape 18 continuously extends between the input reel 16 and the output reel 44, the system 10 can be operated in a variety of different ways to fabricate a sintered article. For example, at block 212a, the conveyor material 56 is optionally stopped after attachment of the jumper film and movement of the tape 18 through the channel 104 is facilitated via rotation of the input reel 16 and the output reel 44. As a result, the tape 18 is dragged over the conveyor material 56 between the conveyor unwind roller 52 and conveyor wind roller 54 and within the heating station 34.Dragging the tape 18 over stationary material is similar to how certain existing sintering systems operate. Alternatively, at block 212b, the conveyor material 56 is moved as the tape 18 advances through the heating station 34 in the downstream direction 11. As described herein, the conveyor material 56 can be moved in the downstream direction 11 during sintering. In embodiments, the conveyor material 56 is moved in the downstream direction 11 at the same rate that the tape 18 is advanced through the heating station 34 via rotation of the input reel 16 and the output reel 44. That is, the conveyor material 56 can be moved at a rate so that the tape 18 does not slide relative to the conveyor material 56 (e.g., the conveyor material 56 may be moved at a rate slightly less than the feed rate of the tape 18 to account for shrinkage of the tape 18 during sintering) to minimize tension applied to the tape 18 via the conveyor material 56. Alternatively, the conveyor material 56 can be advanced at a rate that is less than or greater than that associated with the tape 18 to impart different tensile distributions to the tape 18 during sintering. Additionally, the conveyor material 56 can be moved in the upstream direction as the tape 18 advances through the channel 104 in the downstream direction 11. For example, the conveyor material 56 can move in the upstream direction at a slower rate than the tape 18 advances in the downstream direction 11 so that the tape 18 is dragged over the moving conveyor material 56. Such motion of the conveyor material 56 may apply tension to the entire portion of the tape 18 in contact with the conveyor material 56, which may enhance thickness uniformity of the sintered article over implementations in which the tape 18 is only tensioned outside of the heating station 34.

[0075] Whether or not the conveyor material 56 is moved after the end of the tape 18 is attached to the output reel 44, at block 214, as the tape 18 advances through the channel 104 in the downstream direction, the heating station 34 (or a sintering station therein) is operated under firing conditions (e.g., to reach a peak temperature that is greater than or equal to 700°C) as the sintered tape material 40 continues to be taken up into the output reel 44. In embodiments, the tape 18 can be partially sintered to produce a bisque fired tape that is taken up into the output reel 44 or fully sintered. As used herein, the term “steady-state sintering” refers to operating the system 10 such that the temperature profile of the heating station 34 so that the manner with which the inorganic material in the tape 18 is sintered is not actively changed. In an example, steady-state sintering can include operating the heating station 34 to provide a consistent temperature profile and feeding the tape at a constant rate to provide consistent sintering across the tape 18.

[0076] Embodiments of the sintered articles formed using the systems and methods described herein will now be described. The sintered articles may be provided in the form of a sintered tape (i.e., a continuous sintered article) or a discrete sintered article(s). Unless otherwise indicated, the term “sintered article” is intended to refer to both a continuous sintered article and a discrete sintered article(s). In addition, “sintered” refers to both partially sintered articles and fully sintered articles. In one aspect, embodiments of the sintered article comprise dimensions and exhibit uniformity of certain properties along these dimensions. Another aspect pertains to embodiments of a rolled sintered article, and yet another aspect pertains to embodiments of a plurality of discrete sintered articles.

[0077] Referring to FIG. 3, a sintered article 1000 according to one or more embodiments includes a first major surface 1010, a second major surface 1020 opposing the first major surface, and a body 1030 extending between the first and second surfaces. The body 1030 has a thickness (t) defined as a distance between the first major surface and the second major surface, a width (W) defined as a first dimension of one of the first or second surfaces orthogonal to the thickness, and a length (L) defined as a second dimension of one of the first or second surfaces orthogonal to both the thickness and the width. In one or more embodiments, the sintered article includes opposing minor surfaces 1040 that define the width (W). In specific embodiments, sintered article 1000, as described herein, is an example of sintered tape material 40 produced using system 10, albeit some tapes of the present technology may be longer than the tape shown in FIG. 3.

[0078] In one or more embodiments, the sintered article is a continuous sintered article having a width of about 5 mm or greater, a thickness in a range from about 3 pm to about 1 mm, and a length in a range of about 300 cm or greater. In one or more embodiments, the sintered article has a width in a range from about 5 mm to about 200 mm, from about 10 mm, from about 20 mm to about 200 mm, from about 30 mm to about 200 mm, from about 50 mm to about 200 mm, from about 5 mm to about 75 mm, from about 5 mm to about 50 mm, from about 5 mm to about 40 mm, from about 5 mm to about 30 mm, from about 5 mm to about 20 mm, or from about 5 mm to about 10 mm.

[0079] In one or more embodiments, the sintered article has a thickness (t) in a range from about 3 pm to about 1 mm, from about 10 pm to about 1 mm, from about 15 pm to about 1 mm, from about 20 pm to about 1 mm, from about 25 pm to about 1 mm, from about 30 pm to about 1 mm, from about 35 pm to about 1 mm, from about 3 pm to about 500 pm, from about 3 pm to about 400 pm, from about 3 pm to about 300 pm, from about 3 pm to about200 pm, from about 3 pm to about 100 pm, from about 3 pm to about 90 pm. from about 3 pm to about 80 pun, from about 3 pun to about 70 pun, from about 3 pun to about 60 pun, from about 3 pun to about 50 pun, from about 3 pun to about 45 pun, from about 3 pun to about 40 pun, from about 3 pun to about 35 pun, or from about 3 pun to about 30 pun.

[0080] In one or more embodiments, the sintered article is continuous and has a length L in a range from about 300 cm to about 500 m, from about 300 cm to about 400 m, from about 300 cm to about 200 m, from about 300 cm to about 100 m, from about 300 cm to about 50 m, from about 300 cm to about 25 m, from about 300 cm to about 20 m, from about 350 cm to about 500 m, from about 400 cm to about 500 m, from about 450 cm to about 500 m, from about 500 cm to about 500 m, from about 550 cm to about 500 m, from about 600 cm to about 500 m, from about 700 cm to about 500 m, from about 800 cm to about 500 m, from about 900 cm to about 500 m, from about 1 m to about 500 m, from about 5 m to about 500 m, from about 10 m to about 500 m, from about 20 m to about 500 m, from about 30 m to about 500 m, from about 40 m to about 500 m, from about 50 m to about 500 m, from about 75 m to about 500 m, from about 100 m to about 500 m, from about 200 m to about 500 m, or from about 250 m to about 500 m.

[0081] In some embodiments, the sintered article has a continuous, unbroken length L of at least 5 mm, such as at least 25 mm, such as at least 1 cm, such as at least 15 cm, such as at least 50 cm, such as at least 1 m, such as at least 5 m, such as at least 10 m, and / or no more than 5 km, such as no more than 3 km, such as no more than 1 km, such as no more than 500 m, such as no more than 300 m, such as no more than 100 m. In other embodiments, the sintered article has a different length L. Such continuous long lengths, particularly of materials and qualities disclosed herein, may be surprising to those of skill in the art without technologies disclosed herein, such as the controlled separation, tension control, sintering zones, binder removal techniques, etc.

[0082] In one or more embodiments, the body of the sintered article includes a sintered inorganic material. In one or more embodiments, the inorganic material includes an interface having a major interface dimension of less than about 1 mm. As used herein, the term “interface” when used with respect to the inorganic material is defined as including either a chemical inhomogeneity or a crystal structure inhomogeneity or both a chemical inhomogeneity and a crystal structure inhomogeneity.

[0083] Exemplary inorganic materials include ceramic materials, glass ceramic materials and the like. In some embodiments, the inorganic material may include any one or more of a piezoelectric material, a thermoelectric material, a pyroelectric material, a variable resistance material, or an optoelectric material. Specific examples of inorganic materials include zirconia (e.g., yttria-stabilized zirconia), alumina, spinel, garnet, lithium lanthanum zirconium oxide (LLZO), cordierite, mullite, perovskite, pyrochlore, silicon carbide, silicon nitride, boron carbide, sodium bismuth titanate, barium titanate, titanium diboride, silicon alumina nitride, aluminum oxynitride, or a reactive cerammed glass-ceramic (a glass ceramic formed by a combination of chemical reaction and devitrification, which includes an in situ reaction between a glass frit and a reactant powder(s)).

[0084] In one or more embodiments, the sintered article may be planar. In one or more embodiments, a portion of the sintered article or a discrete sintered article (as will be described herein) may have a have a three-dimensional shape. For example, in one or more embodiments, a portion of the sintered article or a discrete sintered article may have a saddle shape (which has a convex shape along the width and a concave shape along the length, or a concave shape along the width and a convex shape along the length). In one or more embodiments, a portion of the sintered article or a discrete sintered article may have a c-shape (which has a single concave shape along the length). In one or more embodiments, the shape magnitude (which means the maximum height of the portion of the sintered article or a discrete sintered article measured from the plane on which it is disposed) is less than about 0.75 mm (e.g., about 0.7 mm or less, 0.65 mm or less, 0.6 mm or less, 0.55 mm or less, 0.5 mm or less, 0.45 mm or less, 0.4 mm or less, 0.35 mm or less, 0.3 mm or less, 0.25 mm or less, 0.2 mm or less, 0. 15 mm or less, or 0. 1 mm or less).

[0085] Spooling of a continuous sintered article (and in particular, a continuous sintered inorganic material such as ceramics) onto a core presents several challenges because the sintered article has cross web shape, and web tensions that the sintered article can tolerate, particularly in the binder bum out and bisque states, are extremely low (e.g., tensions of gram level magnitude). Furthermore, the modulus of the sintered material can be very high (e.g., up to and including about 210 GPa) and therefore, the sintered article does not stretch under tension and, when wound around a core, the resulting wound roll integrity may be poor. During handling the successive convolutions, a continuous sintered article can easily telescope (i.e., the successive wraps can move out of alignment).

[0086] According to another aspect, the sintered article may be a sintered tape material that is rolled into a rolled sintered article as shown in FIG. 4A. In such embodiments, the rolled sintered article includes a core 1100 and a sintered article 1200 (according to one or more embodiments described herein) wound around the core. In one or more embodiments, the core is cylindrical and has a diameter 1240 of less than 60 cm (or about 20 inches). For example, the core may have a diameter of about 55 cm or less, 50 cm or less, about 48 cm or less, about 46 cm or less, about 45 cm or less, about 44 cm or less, about 42 cm or less, about 40 cm or less, about 38 cm or less, about 36 cm or less, about 35 cm or less, about 34 cm or less, about 32 cm or less, about 30 cm or less, about 28 cm or less, about 26 cm or less, about 25 cm or less, about 24 cm or less, about 22 cm or less, about 20 cm or less, about 18 cm or less, about 16 cm or less, about 15 cm or less, about 14 cm or less, about 12 cm or less, about 10 cm or less, about 8 cm or less, about 6 cm or less, about 5 cm or less, about 4 cm or less, or about 2 cm or less, and greater than 1 cm. In other embodiments the core is otherwise shape and the roll bends around the core in arcs corresponding to the above diameter dimensions.

[0087] In one or more embodiments, the sintered article wound around the core is continuous and has the dimensions otherwise described herein (e.g., a width that is about 5 mm or greater, a thickness in a range from about 3 pm to about 1 mm, and a length is about 30 cm or greater).

[0088] Spooling of a continuous sintered article (and in particular, a continuous sintered inorganic material such as ceramics) onto a core presents several challenges because the sintered article has cross web shape, and web tensions that the sintered article can tolerate, particularly in the binder bum out and bisque states, are extremely low (e.g., tensions of gram level magnitude). Furthermore, the modulus of the sintered material can be very high (e.g., up to and including about 210 GPa) and therefore, the sintered article does not stretch under tension and, when wound around a core, the resulting wound roll integrity may be poor. During handling the successive convolutions, a continuous sintered article can easily telescope (i.e., the successive wraps can move out of alignment).

[0089] Applicants have found that rolled sintered article of one or more embodiments has superior integrity by using a compliant interlayer support material when spooling the continuous sintered article onto a core. In one or more embodiments, the continuous sintered article is disposed on an interlayer support material and the continuous sintered article and interlayer support material are wound around the core such that each successive wrap of thecontinuous sintered article is separated from one another by the interlayer support material. As described above with reference to FIG. 3, the sintered article (or sintered tape material 40) is wound upon output reel 44. The interlayer support material 46 is or may be paid off of a reel 48 and the interlayer support material 46 is or may be wound onto output reel 44 such that a layer of interlayer support material 46 is located between each layer, most, or at least some layers of sintered article 1000 (e.g., sintered article 1000 or sintered tape material 40) on output reel 44.

[0090] Referring to FIG. 4B, a detailed cross-sectional view of the rolled sintered article 1200 of FIG. 4A is shown according to an exemplary embodiment, where the sintered article 1200 has been twice rolled around the core 1100 and interlayer support material 46 is positioned between the sintered article 1200 and the core 1100, and then between successive winds of the sintered article 1200. As may be intuitive from FIG. 4B, when viewed from an end, the sintered article 1200 (in this case a tape) and the interlayer support material 46 form intertwined spirals about the core 1100. In other contemplated embodiments, the sintered article may be cut into discrete sheets and still wound on a core and separated from adjoining winds by an interlayer support material 46, such as where the net length of the sheets when added together is a length L as described herein. As shown in FIG. 4B, in various embodiments, the rolled sintered article includes interlayer support material 46 between each layer of rolled sintered article (e.g., sintered article 1000, sintered article 1200 or sintered tape material 40) is shown according to an exemplary embodiment. In various embodiments, the interlayer support material includes a first major surface and a second major surface opposing the first major surface, an interlayer thickness (t) defined as a distance between the first major surface and the second major surface, an interlayer width defined as a first dimension of one of the first or second surfaces orthogonal to the interlayer thickness, and an interlayer length defined as a second dimension of one of the first or second major surfaces orthogonal to both the interlayer thickness and the interlayer width of the interlayer support material. In one or more exemplary embodiments, the interlayer thickness is greater than the thickness of the sintered article. In one or more embodiments the interlayer width may be greater than the width of the rolled sintered article.

[0091] Referring to FIG. 4A, in one or more embodiments, the rolled article is on a cylindrical core and has a diameter 1220 and a side wall width 1230 that are substantially constant. The interlayer support material enables spooling of the continuous or non- continuous sintered article around the core, without causing telescoping, which can increasethe side wall width of the rolled article. In some embodiments, the core comprises a circumference and a core centerline along the circumference, the continuous sintered article comprises an article centerline along a direction of the length, and the distance between the core centerline and the article centerline is 2.5 mm or less, along at least 90% or the entire length of the continuous or non-continuous sintered article.

[0092] In one or more embodiments, the rolled article comprises a frictional force between the interlayer support material and the continuous or non-continuous sintered article that is sufficient to resist lateral telescoping of the successive convolutions in the wound roll, even when very low tension is applied to the interlayer support material. A constant tension may be applied to the interlayer support material; however, the tension applied to the interior portions of the rolled article toward the core may be greater than the tension applied to exterior portions of the rolled article away from the core due to the diameter of the rolled article increasing from the core to the exterior portions as more interlayer support material and continuous sintered article is wound around the core. This compresses or may compress the rolled article, which, when coupled with the friction between the interlayer support material and the continuous sintered article, prevents or limits telescoping and relative movement between sintered article surfaces to at least help prevent defects.

[0093] In one or more embodiments, the interlayer support material comprises any one of or both a polymer and a paper. In some embodiments, the interlayer support material is a combination of polymer and paper. In one or more embodiments, the interlayer support material may include a foamed polymer. In some embodiments, the foamed polymer is closed cell.

[0094] According to another aspect, the sintered articles described herein may be provided as a plurality of discrete sintered articles, as described herein with respect to FIG. 9. In one or more embodiments, the discrete sintered articles may be formed from a rolled sintered article or a continuous sintered article, as described herein. For example, the discrete sintered articles may be laser cut or otherwise separated from a larger sintered article (which may be in sheet or tape form). Alternatively, each of the discrete sintered articles can be formed of a plurality of discrete green bodies, as described herein with respect to FIG. 9. The conveyor system described herein beneficially enables such discrete green bodies to be sintered without being connected to one another.

[0095] In one or more embodiments, each of the plurality of discrete sintered articles has a uniformity or consistency with respect to some or all others of the plurality of discrete sintered articles, as may be due to the improved methods and material properties described herein. In one or more embodiments, each of the plurality of sintered articles include a first major surface, a second major surface opposing the first major surface, and a body extending between the first and second surfaces. The body includes a sintered inorganic material and a thickness (t) defined as a distance between the first major surface and the second major surface, a width defined as a first dimension of one of the first or second surfaces orthogonal to the thickness, and a length defined as a second dimension of one of the first or second surfaces orthogonal to both the thickness and the width. As may be intuitive, the discrete sheets or other sintered articles cut or formed from a longer tape have uniform and consistent compositions as disclosed above, uniform and consistent crystal structure, uniform and consistent thickness, levels of defects, and other properties described herein that are or may be present in a tape or other elongate article manufactured with the inventive equipment and methods disclosed herein.Example

[0096] Embodiments of the present disclosure may be further understood in view of the following example.

[0097] An example ribbon was fabricated via the system similar to the system 10 described herein. Particularly, a spool of green tape material was disposed an on input reel. The green tape material contained grains of tantalum-lithium lanthanum zirconium oxide dispersed in a polypropylene carbonate binder package with 3 excess wt% lithium carbonate. To initiate the sintering process, the green tape material 20 was placed on graphite foil conveyor material. FIG. 5 A depicts the green tape material 500 disposed on an input reel 502 and tensioned for placement on the conveyor material 504. In FIG. 5 A, the conveyor material 504 is moved so that a portion of the green tape material 500 is already disposed in a heating station 506. In this example, the input reel 502 was rotated to feed the green tape material 500 onto the conveyor material 504 at a faster rate than the conveyor material 504 was moved via rotation of a conveyor unwind roller (not shown) to compensate for shrinkage of the tape material within the heating station 506. The heating station 506 comprised a binder station having zones operating at temperatures within a range from 50°C to 600°C and a sintering stationhaving zones operating at temperatures within a range from 800°C to 1700°C. The tape was advanced through the heating station 506 at a rate of 2 inches per minute.

[0098] FIG. 5B depicts sintered tape 508 at a fired end of the system (downstream of the heating station 506 depicted in FIG. 5 A) with the conveyor material 504 stopped. As shown, an end 510 of the tape is disposed on the conveyor material 504, which is wrapped around a conveyor wind roller 512. The end 510 of the sintered tape 508 is attached to an output reel 514 via a jumper film 516 adhered to both the sintered tape 508 and the output reel 514. As shown in FIG. 5B, when initially attached, the jumper film 516 was not in a tensioned state. After attachment of the jumper film 516, with the conveyor material 504 still stopped, the input reel 502 and the output reel 514 were advanced to slide the tape over the conveyor material 504. FIG. 5C depicts the end 510 of the sintered tape 508 being disposed on the output reel 514 after the onset of winding. Steady state continuous sintering is then initiated with the input reel 502 and output reel 514 operating to feed the tape through the heating station 506 at a substantially constant speed. FIG. 5D depicts the sintered tape 508 after a time period of steady state sintering, in which the sintered tape 508 is wound several times around a core 518 having a 5 inch diameter to provide a continuously wound sintered article.

[0099] The sintered article formed in accordance with this example had a length of about 20 feet and had a very uniform width. FIG. 5E depicts of the sintered tape 508 just upstream of the heating station 506 (see FIG. 5A). In this example the width was measured to be approximately 38 mm, and varies by well less than 5% over the depicted segment. X-ray diffraction analysis revealed that the sintered tape 508 had a body exhibited the composition provided below in Table 1.Table 1As shown, the tape had a body, where greater than 95% of the body by weight consisted of cubic lithium garnet crystals. The body did not include lanthanum zirconate. FIG. 6A is a scanning electron microscope image of the sintered tape 508, revealing the tape to have a thickness of about 31.5 pm. FIG. 6B depicts a cross-section after being subjected to focused ion beam polishing. The dark regions are O2 enriched pores. It is believed that these poresare likely filled Li20 rather than being open porosity. It is believed that this closed porosity is due to the excess Li-additions to the green tape.

[0100] Six 9 mm segments of the sintered tape were taken and the sampled throughout the widths of each segment to determine a porosity distribution for each segment. The total porosity was estimated to be less than 10% by volume (approximately 6.3%). Porosity size distribution histograms were generated for all pores. The results are shown in FIG. 7. As shown, the mean pore size was measured to be 0.23 pm. Separate histograms for small and large pores revealed that smaller pores had a mean size of 0.17 histograms and larger pores had a mean size of 1.5 pm.

[0101] FIG. 8 is an SEM image of a major surface of the sintered tape material 40. The image was taken with a 14.6 nm resolution to facilitate determining the grain size distribution of the portion of the surface imaged. From the imaging, an average grain size was determined to be about 1.12 pm. Images show clusters of smaller grains, which lower the effective average of the calculated grain size. Such smaller grain clusters show a grain size of about 0.35 pm to be a most common size for such smaller grains. Larger grains had an average size of 1.3 pm. The grain size distribution was bimodal, with these smaller and larger grain sizes being associated with peaks in the histogram.

[0102] While the preceding example described forming a continuous sintered article that is wound around a spool. The systems and methods described herein can be used to fabricate discrete sintered articles having lengths less than the dimensions of the heating station. FIG. 9 depicts a sintering system 900 for sintering a plurality of discrete sintered articles, according to one or more embodiments of the present disclosure. The system 900 generally includes similar components as the system 10 described herein with respect to FIG. 1, with the exception that the system 900 does not include the input side 12 and the output side 14 described herein. This exemplifies that only the conveyor system 50 and the heating station 34 described of the system 10 described herein can be used to fabricate a plurality of sintered articles.

[0103] As shown, a plurality of discrete sections of tape material 902 can be placed on the conveyor material 504 and conveyed at a suitable rate through the heating station 34 to fabricate a plurality of discrete sintered articles. In embodiments, multiple segments of conveyor material can be used, and stacks of sections of tape material can be disposed on topof one another with the conveyor material being disposed between each section in the stack. This provides a way of increasing method throughput by multiples.

[0104] The plurality of discrete sections of tape material 902 can be introduced into the system 900 in variety of ways. For example, the plurality of sections of tape material 902 can be introduced as discrete sections of green tape material (e.g., containing relatively high levels of organic binder associated with no sintering) onto the conveyor material 56 upstream of the heating station 34. In such embodiments, the plurality of discrete sections of tape material are separately introduced as completely green articles (similar in composition to the green tape material 20 described herein). Such green articles can be, for example, cut from a reel of the green tape material 20 or separately cast as green articles in a discrete forming method.

[0105] In embodiments, the plurality of discrete segments of tape material 902 can be introduced onto the conveyor material 56 as at least partially sintered segments. In an example, the system 10 is operated herein in accordance with the method described herein with respect to FIG. 2 to fabricate a continuous sintered article from the green tape material 20, with the inorganic grains being at least partially sintered to on another and the tape 18 being completely disposed on the output reel 44. The at least partially sintered article may then be cut into the plurality of discrete segments of tape material 902 and placed on the conveyor material 56. Such a method may allow the heating station 34 to potentially complete sintering of the articles (if the ribbon was only partially sintered during the continuous method). Alternatively or additionally, the heating station 34 can be used to perform post-sintering heat treatments on the discrete articles.

[0106] In view of the foregoing, the conveyor system described herein adds several capabilities to existing sintering systems by providing an additional method that can be used to initiate a continuous sintering method for fabricating a relatively long sintered article. Additionally, by eliminating the need for a continuous connection between the tape material and portions of the system upstream and downstream of the heating station, the conveyor system enables the fabrication of discrete articles without changing any equipment that also can be used for fabricating long, continuous sintered articles. This enables hybrid processes that where the system can be used to sinter and / or heat treat both long, continuous ribbons of material and discrete articles.

[0107] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that any particular order be inferred. In addition, as used herein, the article “a” is intended to include one or more component or element, and is not intended to be construed as meaning only one. Similarly, pieces of equipment and method steps disclosed herein may be used with materials other than continuous tape. For example, while continuous tape may be particularly efficient for roll-to-roll methoding, Applicants have demonstrated that a sled of zirconia or other refractory material may be used to draw discrete sheets of material or other articles through equipment disclosed herein.

[0108] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the disclosed embodiments. Since modifications, combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the embodiments may occur to persons skilled in the art, the disclosed embodiments should be construed to include everything within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A method of forming a sintered tape material comprising grains of inorganic material, the method comprising: placing a leading section of the tape on a conveyor material such that a first major surface of tape in the leading section directly contacts a portion of the conveyor material; moving the leading section through a heating station by moving the portion of the conveyor material through the heating station in a downstream direction, wherein the leading section is in frictional engagement with the portion of the conveyor material; and heating at least a portion of the tape within the heating station to a temperature above 500°C such that the inorganic material of the tape is sintered as it moves through the heating station, wherein the portion of the conveyor material that moves through the heating station is disposed both upstream and downstream of the heating station.

2. The method of claim 1, further comprising unwinding the tape from an input reel disposed upstream of the heating station, wherein some of the tape is still wound around the input reel when the leading section is placed on the portion of the conveyor material, wherein the unwinding of the tape from the input reel occurs at a first feed rate in the downstream direction that is greater than a rate at which the conveyor material is moved through the heating station to compensate for shrinkage of the tape within the heating station.

3. The method of claim 2, wherein the tape is connected to the input reel while the inorganic material of the tape is sintered.

4. The method of claim 3, further comprising attaching the leading section with an output reel disposed downstream of the heating station and rotating the output reel as the inorganic material is sintered to form a roll of the sintered tape material.

5. The method of claim 4, wherein the conveyor material is a sheet of material that extends through the heating station between a conveyor unwind roller disposed upstream of the heating station and a conveyor wind roller disposed downstream of the heating station.

6. The method of claim 5, wherein moving the portion of the conveyor material comprises rotating the conveyor unwind roller and the conveyor wind roller.

7. The method of claim 6, further comprising, once the leading section is attached to the output reel, rotating the input reel and the output reel to feed the tape through the heating station at a second feed rate to at least partially sinter the grains to one another within the heating station.

8. The method of claim 7, wherein the conveyor material is stopped once the leading section is attached to the output real such that, during sintering of the remainder of the tape, the remainder of the tape is dragged over the conveyor material.

9. The method of claim 7, further comprising, when the sintering station operates to at least partially sinter the grains to one another in a steady state, the conveyor wind roller and the conveyor unwind roller are rotated to move the conveyor material in the heating station.

10. The method of claim 9, wherein, while the sintering station operates in the steady state, the conveyor unwind roller and conveyor wind roller are rotated to advance the conveyor material in the downstream direction at a rate that is less than the second feed rate so that shrinkage of the tape during sintering is compensated.

11. The method of claim 9, wherein, while the sintering station operates in the steady state, the conveyor unwind roller and conveyor wind roller are rotated to either: (a) advance the conveyor material in the downstream direction at a rate that varies from that at which the tape travels through the heating station to place the tape under tension; or (b) move the conveyor material in the upstream direction.

12. The method of any of claims 7-11, wherein, as the conveyor wind roller rotates, segments of the conveyor material that contact the tape are rolled into the conveyer wind roller and replaced by new segments of the conveyor material that have not previously contacted the tape.

13. The method of any of claims 1-2, wherein the tape comprises a plurality of discrete sections of tape material and the leading section comprise an entirety of each of the plurality of discrete sections of tape material.

14. The method of claim 13, wherein the placing the leading section of the tape on the conveyor material comprises placing the plurality of discrete sections of tape material onto the conveyor material upstream of the heating station as a plurality of discrete green bodies.

15. The method of claim 13, wherein the plurality of discrete sections of tape material are cut from a ribbon of partially sintered tape material.

16. An article formed by the method according to any of claims 1-15, the article comprising a body comprising ceramic grains sintered to one another, wherein the grains comprise lithium, wherein greater than 95% of the body by weight consists of cubic lithium garnet crystals, wherein the body comprises: a plurality of pores such that the body exhibits a total porosity of less than or equal to 10%, a thickness, measured between first and second major surfaces of the body, that is in a range from 3 pm to 50 pm, a width, measured in a first direction perpendicular to the thickness, of 5 mm or greater, a length, measured in a second direction perpendicular to the first direction, 5 cm or greater, and an average grain size of 5 pm or less.

17. The article of claim 16, wherein the grains do not comprise lanthanum zirconate.

18. The article of any of claims 16-17, wherein the body has a length of at least 5 m.

19. A system for sintering a tape comprising grains of inorganic material, the system comprising: a heating station comprising an entrance, an exit, and a channel extending between the entrance and the exit; a conveyor unwind roller disposed upstream of the entrance; a conveyor wind roller disposed downstream of the exit; and conveyor material extending through the channel between the conveyor unwind roller and the conveyor wind roller, wherein: the conveyor material is attached to both the conveyor unwind roller and conveyor wind roller, the conveyor unwind roller and conveyer wind roller are rotatable such that a segment of the conveyor material that is disposed within the channel is alterable in either an upstream direction or a downstream direction, and the conveyor material is configured to directly contact the tape when a segment of the tape is disposed within the channel to sinter the grains.

20. The system of claim 19, further comprising: an input reel from which the tape is unwound upstream of the heating station; and an output reel that receives the tape downstream of the heating station after the tape is sintered, wherein the tape continuously extends from the input reel to the output reel and is in direct contact with the conveyor material within the channel.

21. The system of claim 20, wherein the conveyor unwind roller and the conveyor wind roller are configured to rotate so that the conveyor material does not slide relative to the tape as the tape is conveyed through the channel.

22. The system of claim 20, wherein the conveyor unwind roller and the conveyor wind roller are configured to stop movement of the conveyor material within the channel so that the tape can be dragged over the conveyor material.

23. The system of claim 20, wherein the conveyor unwind roller and the conveyor wind roller are configured to rotate to advance the conveyor material through the channel at a different rate than a rate at which the tape is fed through the channel to apply tension to the tape.

24. The system of any of claims 19-23, wherein a sintered end of the tape is attached to the uptake reel via a jumper film adhered thereto.

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