[Object] There is provided a porous sintered body has a uniform porosity, a high level of freedom in body formation which allows formation into varieties shapes and various levels of porosity, and a very large surface area. [Solution] The porous sintered body includes: hollow cores which follow a vanished shape of an interlaced or otherwise structured fibriform vanisher material; sintered walls 226 which extend longitudinally of the cores and obtained by sintering a first sintering powder held around the cores; and voids formed between the sintered walls. The cores and the voids communicate with each other via absent regions formed in the sintered walls. The sintered walls have surfaces formed with a sintered microparticulate layer 232 made from a material containing a second sintering powder which has a smaller diameter than the first sintering powder, and has predetermined pores 231.

[Object] There is provided a porous sintered body has a uniform porosity, a high level of freedom in body formation which allows formation into varieties shapes and various levels of porosity, and a very large surface area. [Solution] The porous sintered body includes: hollow cores which follow a vanished shape of an interlaced or otherwise structured fibriform vanisher material; sintered walls 226 which extend longitudinally of the cores and obtained by sintering a first sintering powder held around the cores; and voids formed between the sintered walls. The cores and the voids communicate with each other via absent regions formed in the sintered walls. The sintered walls have surfaces formed with a sintered microparticulate layer 232 made from a material containing a second sintering powder which has a smaller diameter than the first sintering powder, and has predetermined pores 231.

The present invention relates to granular composite density enhancement, and related methods and compositions. The application where the properties are valuable include but are not limited to: 1) additive manufacturing (“3D printing”) involving metallic, ceramic, cermet, polymer, plastic, or other dry or solvent-suspended powders or gels, 2) concrete materials, 3) solid propellant materials, 4) cermet materials, 5) granular armors, 6) glass-metal and glass-plastic mixtures, and 7) ceramics comprising (or manufactured using) granular composites.

Provided herein are methods of preparing a metal foam that include the steps of forming a metal foam precursor with a slurry comprising a metal component, a dispersant, a binder and an antisolvent, and sintering the metal foam precursor. Such methods may provide metal foams having various pore sizes. Methods further include forming a thin metal foam on a base material.

A method for preparing metal/metal interpenetrating phase composites is provided. The method includes forming a preform using additive manufacturing. The preform defines a materially continuous three-dimensional open-cell mesh structure. The preform includes a first metal having a melting point. The method further includes pre-heating the preform to a first temperature less than the melting point of the first metal. The method includes infiltrating the preform with a second metal in liquid form. The second metal has a melting point lower than the melting point of the first metal. The method also includes allowing the second metal to cool and form a solid matrix. The solid matrix defines a continuous material network.

A multi-step method to produce materials, and coatings of materials, which has three key characteristics. The first is that the density of the resulting materials or coatings can be controllably and widely variable from less than ten percent of normal density up to normal density. The second key characteristic of the invention is the use of starting materials having powders that have grains (particles) with one, two or three dimensions on the size scales of nanometers or micrometers. The third major characteristic part of the invention is the use of microwave radiation or induction heating to quickly raise the temperature of the powders to produce materials or coatings before deleterious diffusion and densification can occur. These features produce new types of materials with properties favorable to many applications, such as chemical and other catalysis, electrolysis in batteries and fuel cells, and light weight structural components.

A multi-step method to produce materials, and coatings of materials, which has three key characteristics. The first is that the density of the resulting materials or coatings can be controllably and widely variable from less than ten percent of normal density up to normal density. The second key characteristic of the invention is the use of starting materials having powders that have grains (particles) with one, two or three dimensions on the size scales of nanometers or micrometers. The third major characteristic part of the invention is the use of microwave radiation or induction heating to quickly raise the temperature of the powders to produce materials or coatings before deleterious diffusion and densification can occur. These features produce new types of materials with properties favorable to many applications, such as chemical and other catalysis, electrolysis in batteries and fuel cells, and light weight structural components.

Examples for refining the microstructure of metallic materials used for additive manufacturing are described herein. An example can involve generating a first layer of an integral object by heating a metallic material to a molten state such that the metallic material includes a solid-liquid interface. The example can further involve applying an electromagnetic field or vibrations to the metallic material of the first layer. In some instances, the electromagnetic fields or vibrations perturb the first layer of metallic material causing nucleation sites to form at the solid-liquid interface of the metallic material in the molten state. The example also includes generating a second layer coupled to the first layer of the integral object. Generating the second layer increases a number of nucleation sites at the solid-liquid interface of the metallic material in the molten state. Each nucleation site can grows a crystal at a spatially-random orientation.

A method for producing a layer of a device for electromagnetic radiation absorption, includes: providing a ply of powder material in the layer to be produced of the device; providing a predefined concentration distribution of particles for electromagnetic radiation absorption in the layer; providing a first binder and a second binder for the powder materials, wherein the first binder includes particles for the absorption of electromagnetic radiation, wherein the second binder includes a lower concentration of identical and/or different particles than the first binder; determining a mixing ratio between the first binder and the second binder for every position in the layer; selecting a position of the layer; mixing the first and second binder according to the mixing ratio for the selected position; wetting the powder material at the selected position using the mixed first and second binders; and repeating selecting, mixing, and wetting to produce the layer.

The present invention addresses the problem of providing a sintered alloy valve guide capable of inhibiting valve adhesion even in a high-temperature environment. The problem can be solved by a sintered alloy valve guide impregnated with a lubricating oil including pores that are sealed on the valve guide outer circumferential surface. More particularly, the problem is solved by the sealing step of performing a sealing treatment of pores on the outer circumferential surface of a sintered body impregnated with a lubricating oil.