A method of manufacturing a catalytic sieve includes providing starting materials of an aggregate, a cementing agent, a sublimation agent and water. The sublimation agent (between 25% and 50% by weight of the cementing agent) is selected from molybdenum disulfide, tungsten disulfide, vanadium disulfide, copper sulfate, and combinations thereof. The aggregate contains at least 2% by weight of at least one transition metal. The method includes mixing the starting materials to achieve a mixture, placing the mixture into a form, and curing the mixture in the form to allow the mixture to become a solidified unit defined by a minimum dimension of thickness, length, width or diameter. The method further includes placing the solidified unit into a kiln, heating the kiln to 1115°−1350° C., maintaining the kiln at the temperature for between 10-60 minutes per centimeter of the minimum dimension, and removing the solidified unit from the kiln.

A method of manufacturing a catalytic sieve includes providing starting materials of an aggregate, a cementing agent, a sublimation agent and water. The sublimation agent (between 25% and 50% by weight of the cementing agent) is selected from molybdenum disulfide, tungsten disulfide, vanadium disulfide, copper sulfate, and combinations thereof. The aggregate contains at least 2% by weight of at least one transition metal. The method includes mixing the starting materials to achieve a mixture, placing the mixture into a form, and curing the mixture in the form to allow the mixture to become a solidified unit defined by a minimum dimension of thickness, length, width or diameter. The method further includes placing the solidified unit into a kiln, heating the kiln to 1115°−1350° C., maintaining the kiln at the temperature for between 10-60 minutes per centimeter of the minimum dimension, and removing the solidified unit from the kiln.

A method to form a machinable ceramic matrix composite comprises forming a porous ceramic multilayer on a surface of a fiber preform. In one example, the porous ceramic multilayer comprises a gradient in porosity in a direction normal to the surface. In another example, the porous ceramic multilayer includes low-wettability particles having a high contact angle with molten silicon, where an amount of the low-wettability particles in the porous ceramic multilayer varies in a direction normal to the surface. After forming the porous ceramic multilayer, the fiber preform is infiltrated with a melt, and the melt is cooled to form a ceramic matrix composite with a surface coating thereon. An outer portion of the surface coating is more readily machinable than an inner portion of the surface coating. The outer portion of the surface coating is machined to form a ceramic matrix composite having a machined surface with a predetermined surface finish and/or dimensional tolerance.

A method to form a machinable ceramic matrix composite comprises forming a porous ceramic multilayer on a surface of a fiber preform. In one example, the porous ceramic multilayer comprises a gradient in porosity in a direction normal to the surface. In another example, the porous ceramic multilayer includes low-wettability particles having a high contact angle with molten silicon, where an amount of the low-wettability particles in the porous ceramic multilayer varies in a direction normal to the surface. After forming the porous ceramic multilayer, the fiber preform is infiltrated with a melt, and the melt is cooled to form a ceramic matrix composite with a surface coating thereon. An outer portion of the surface coating is more readily machinable than an inner portion of the surface coating. The outer portion of the surface coating is machined to form a ceramic matrix composite having a machined surface with a predetermined surface finish and/or dimensional tolerance.

Provided herein are methods for making a freeze-cast material having a internal structure, the methods comprising steps of: determining the internal structure of the material, the internal structure having a plurality of pores, wherein: each of the plurality of pores has directionality; and the step of determining comprises: selecting a temperature gradient and a freezing front velocity to obtain the determined internal structure based on the selected temperature gradient and the selected freezing front velocity; directionally freezing a liquid formulation to form a frozen solid, the step of directionally freezing comprising: controlling the temperature gradient and the freezing front velocity to match the selected temperature gradient and the selected freezing front velocity during directionally freezing; wherein the liquid formulation comprises at least one solvent and at least one dispersed species; and subliming the at least one solvent out of the frozen solid to form the material.

Provided herein are methods for making a freeze-cast material having a internal structure, the methods comprising steps of: determining the internal structure of the material, the internal structure having a plurality of pores, wherein: each of the plurality of pores has directionality; and the step of determining comprises: selecting a temperature gradient and a freezing front velocity to obtain the determined internal structure based on the selected temperature gradient and the selected freezing front velocity; directionally freezing a liquid formulation to form a frozen solid, the step of directionally freezing comprising: controlling the temperature gradient and the freezing front velocity to match the selected temperature gradient and the selected freezing front velocity during directionally freezing; wherein the liquid formulation comprises at least one solvent and at least one dispersed species; and subliming the at least one solvent out of the frozen solid to form the material.

A process for preparing a porous ceramic body includes forming a green body with a mixture of ceramic material powder, binder material, and pore-forming particles. The process further includes extracting the binder material, decomposing the pore-forming particles, and removing residual organic materials from the green body at respective, progressively higher pre-firing temperatures. After these three stages, the green body is sintered at a still-higher temperature to form the porous ceramic body. Embodiments facilitate manufacturing and can render most or all surface grinding unnecessary, allowing electrode deposition directly onto substantially non-porous surfaces of the porous ceramic body that are naturally formed during sintering. Advantageously, the green body may be formed into net shape by injection molding the mixture that includes the pore-forming particles, and embodiments can result in porous ceramic bodies that are much thicker than currently available, with better structural integrity.

A process for preparing a porous ceramic body includes forming a green body with a mixture of ceramic material powder, binder material, and pore-forming particles. The process further includes extracting the binder material, decomposing the pore-forming particles, and removing residual organic materials from the green body at respective, progressively higher pre-firing temperatures. After these three stages, the green body is sintered at a still-higher temperature to form the porous ceramic body. Embodiments facilitate manufacturing and can render most or all surface grinding unnecessary, allowing electrode deposition directly onto substantially non-porous surfaces of the porous ceramic body that are naturally formed during sintering. Advantageously, the green body may be formed into net shape by injection molding the mixture that includes the pore-forming particles, and embodiments can result in porous ceramic bodies that are much thicker than currently available, with better structural integrity.

A method for manufacturing a concrete product includes providing a metal-based cementing agent, and an acid-based cement reacting agent of the form H.sub.nXO.sub.m, where “X” is an element selected from group consisting of phosphorous, carbon, sulfur and boron, “n” and “m” are selected so that the cement reacting agent is an acid, and “X” will bond with the metal-based cementing agent to form a metal cement. The method further includes providing an aggregate defined by an exposed surface area having metallic aggregate linking elements thereon which can chemically bond with “X” in the presence of the acid-based cement reacting agent, and providing a hydroxide-supplying additive. The method includes combining together the metal-based cementing agent, the acid-based cement reacting agent, the aggregate and the hydroxide-supplying additive, and allowing the metal-based cementing agent and the acid-based cement reacting agent to react and bond with the aggregate to form the concrete product.

A method for producing a form-stable phase-change material to nucleate sugar alcohols includes directionally freezing a slurry of solid chitosan and solvent and additives, providing a frozen slurry including unidirectional pillars of frozen solvent that force suspended solid particles into interstices, exposing the frozen slurry to conditions causing sublimation of the solvent of the frozen slurry to remove frozen solvent and provide a body having pillars of vacancies therein, sintering the body to provide a scaffold including the pillars of vacancies therein, graphitizing the scaffold by heating in argon, treating the scaffold with aqueous base, and adding a molten sugar alcohol phase-change material to the scaffold such that the molten phase-change material is drawn into the pillars of vacancies by capillary action to provide the form-stable phase-change material having reduced hysteresis of the melting point of the sugar alcohol phase-change material.