Abstract: This invention relates to a new class of piezoelectric composites with a radial design. More particularly, the radial design of these new ceramic/polymer composites show a higher sensitivity in the radial direction than conventional tube structured devices. Devices made utilizing this novel design will therefore show significantly enhanced performance in many applications.

Abstract: A process for making ceramic composites includes the steps of: a) forming a polymer composition into a three-dimensional mold; b) filling said three-dimensional mold with one or more ceramic containing compositions; c) heating said filled mold to dry and sinter the ceramic; d) removing at least a portion of said three-dimensional mold thereby forming voids; and e) filling the voids with a second composition which has a piezoelectric coefficient which is substantially different from the piezoelectric coefficient of said ceramic structure. Steps a through e yield a controlled, non-random piezoelectric ceramic composite having 2-3, 3-2 or 3--3 connectivity with respect to the sintered ceramic and the second composition throughout the composite.

Abstract: Solid freeform fabrication techniques are used in direct methods to form photonic bandgap structures, and in indirect methods to form molds for photonic bandgap structures. In the direct methods, solid particulate materials are mixed with a binder and, through a computer-controlled process, are built layer by layer to form the structure. In the indirect methods, unfilled polymeric materials are built layer by layer to form a negative mold for the photonic bandgap structure. The cavities within the mold may then be filled with a slurry incorporating solid particulate materials. Subsequent processing may include mold removal, binder removal, densification and secondary infiltration steps to form a photonic bandgap structure having the desired properties.

Abstract: A fused deposition process is used to form three-dimensional solid objects from a mixture including a particulate composition dispersed in a binder. The article is formed by depositing the mixture in repeated layers of predefined thickness, with each layer solidifying before the next adjacent layer is dispensed. Following formation and a binder removal step, the article may be at least partially densified to achieve preselected properties. The process permits three-dimensional articles to be formed relatively quickly and inexpensively, without the need for molds or other tooling.

Abstract: A ceramic component is manufactured rapidly using a mold made directly from a solid freeform manufacturing process. Solid freeform fabrication, or rapid prototyping, procedures are used to generate molds of materials that are soluble or otherwise fugitive. A gel casting suspension containing ceramic and emulsifying agents is poured into the cavity of the mold and caused to set. The mold is then removed by dissolution or heat treatment, leaving intact the gelcast part. Conventional procedures are then utilized to densify the gelcast component to the required final component. Time consuming and expensive machine tooling procedures are virtually eliminated. Ceramic components are generated rapidly in a cost effective manner.

Abstract: A process for forming novel ceramic composites is described. The disclosed process allows for novel composite designs, including composites with regions containing different materials. Moreover, the disclosed process allows for the manufacture of composites with volume fraction gradients of different types of material. Composites with fine-scale microstructures may be formed.

Abstract: This invention relates to novel oriented piezoelectric ceramic and ceramic/polymer composites. More particularly, it provides a novel piezoelectric composite design wherein the ceramic piezoelectric phase is oriented at an angle with respect to the direction of applied stress, thus giving improved electromechanical properties.

Abstract: A fused deposition process is used to form three-dimensional solid objects from a mixture including a particulate composition dispersed in a binder. The article is formed by depositing the mixture in repeated layers of predefined thickness, with each layer solidifying before the next adjacent layer is dispensed. Following formation and a binder removal step, the article may be at least partially densified to achieve preselected properties. The process permits three-dimensional articles to be formed relatively quickly and inexpensively, without the need for molds or other tooling.

Abstract: A process for forming large-grain polycrystalline films from amorphous films for use as photovoltaic devices. The process operates on the amorphous film and uses the driving force inherent to the transition from the amorphous state to the crystalline state as the force which drives the grain growth process. The resultant polycrystalline film is characterized by a grain size that is greater than the thickness of the film.A thin amorphous film is deposited on a substrate. The formation of a plurality of crystalline embryos is induced in the amorphous film at predetermined spaced apart locations and nucleation is inhibited elsewhere in the film. The crystalline embryos are caused to grow in the amorphous film, without further nucleation occurring in the film, until the growth of the embryos is halted by imgingement on adjacently growing embryos. The process is applicable to both batch and continuous processing techniques.