The present invention is a granular material that can be well recoated regardless of the type of the granular material, and enables a refractory aggregate in an unprinted portion to be used without any regeneration process, in the manufacture of a three-dimensional laminated and shaped mold. This granular material is a granular material for use in three-dimensional laminated mold shaping, and obtained by adding a material that causes a hydration reaction having a moisture absorbing function and generates a catalytic effect to a coating material mixed with or coated with an acid as a catalyst which activates and hardens an organic binder for binding the granular material.

A powder injection molding feedstock includes powder particles, a main binder, and a secondary binder. A glass-transition temperature of the secondary binder is greater than a glass-transition temperature of the main binder, the secondary binder coats the powder particles, and the main binder coats the secondary binder and the powder particles.

The present invention relates to a process for producing a three-dimensional (3D) object by employing a three-dimensional (3D) printing process wherein a granulate having an particle size in the range of 0.2 to 1 mm is used as a starting material to be printed within said 3D printing process, employing a 3D extrusion printer. In one preferred embodiment, the process according to the present invention is employed for producing a 3D greenbody. The invention further relates to 3D objects as such and the corresponding processes for obtaining such 3D objects, in particular a 3D green body, a 3D brown body and a 3D sintered body.

A method for manufacturing a powder injection molding feedstock includes providing a plurality of powder particles and a secondary binder and applying primary kneading in an internal mixer. The primary mixture is cooled and crushed. A main binder is provided and put into the internal mixer to mix with the mixture that being crushed for secondary kneading to obtain the powder injection molding feedstock. Glass-transition temperature of the secondary binder is greater than glass-transition temperature of the main binder. The secondary binder coats the powder particles. The main binder coats the secondary binder and the powder particles.

A method for manufacturing a powder injection molding feedstock includes providing a plurality of powder particles and a secondary binder and applying primary kneading in an internal mixer. The primary mixture is cooled and crushed. A main binder is provided and put into the internal mixer to mix with the mixture that being crushed for secondary kneading to obtain the powder injection molding feedstock. Glass-transition temperature of the secondary binder is greater than glass-transition temperature of the main binder. The secondary binder coats the powder particles. The main binder coats the secondary binder and the powder particles.

The present invention relates to a method for preparing a fully ceramic capsulated nuclear fuel material containing three-layer-structured isotropic nuclear fuel particles coated with a ceramic having a composition which has a higher shrinkage than a matrix in order to prevent cracking of ceramic nuclear fuel, wherein the three-layer-structured nuclear fuel particles before coating is included in the range of between 5 and 40 fractions by volume based on after sintering. More specifically, the present invention provides a composition for preparing a fully ceramic capsulated nuclear fuel containing three-layer-structured isotropic particles coated with the substance which includes, as a main ingredient, a silicon carbine derived from a precursor of the silicon carbide wherein a condition of L.sub.c>L.sub.m at normal pressure sintering is created, where the sintering shrinkage of the coating layer of the three-layer-structured isotropic nuclear fuel particles is L.sub.c and the sintering shrinkage of the silicon carbide matrix is L.sub.m; material produced therefrom; and a method for manufacturing the material. The residual porosity of the fully ceramic capsulated nuclear fuel material is 4% or less.

The present invention is a granular material that can be well recoated regardless of the type of the granular material, and enables a refractory aggregate in an unprinted portion to be used without any regeneration process, in the manufacture of a three-dimensional laminated and shaped mold. This granular material is a granular material for use in three-dimensional laminated mold shaping, and obtained by adding a material that causes a hydration reaction having a moisture absorbing function and generates a catalytic effect to a coating material mixed with or coated with an acid as a catalyst which activates and hardens an organic binder for binding the granular material.

The invention relates to a ceramic feedstock comprising the components a), b) and optionally c), wherein component a) is at least one ceramic material, component b) is at least one binder (B) and optional component c) is at least one additive (A). The ceramic feedstock is preferably provided in form of a filament to be employed in three-dimensional (3D) printing techniques, particularly in a FFF printing process. The inventive ceramic feedstock can, therefore, be successfully employed for the 3D printing of support structures and/or separation layers. Further, the invention also relates to three-dimensional objects as such, in particular three-dimensional green bodies, three-dimensional brown bodies or three-dimensional sintered bodies as well as to a process for the preparation thereof.