A method is provided for producing an article which is transparent to IR wavelength in the region of 4 μm to 9 μm. The method includes the steps of (a) Producing ultra-fine powders of ZnS, (b) followed by pretreatment of the ultra-fine powders under reduced gas conditions including H2, H2S, N2, Ar and mixtures there of (c) followed by vacuum (3×10.sup.−6 torr) treatment to remove oxygen and sulfates adsorbed to the surface disposing a plurality of nano-particles on a substrate, wherein said nanoparticles comprise ZnS with ultra-high purity of cubic phase; (b) subjecting the nano-particles to spark plasma sintering thereby producing a sintered ZnS product with IR transmission reaching 75% in the wavelength range of 4 μm to 9 μm.

Methods for making printed articles from carbon powder are described. Three-dimensional binder jet printing is used to make a printed article from the carbon powder. Methods are also provided for the production of near net shaped carbonized printed articles and graphitized printed articles.

A method is provided for making ceramic bodies having improved properties, such as optical and/or strength properties in which the ceramic bodies are densified by new sintering processes. The sintering profiles may have shorter run times than conventional sintering processes. Ceramic bodies made by these methods are suitable for use in dental applications, for example, as crowns.

The purpose of the present invention is to achieve an in-situ observation of structural change in a shear field of slurry, i.e. an evaluation of a rheology property of slurry containing raw materials of a ceramic as a fluid sample, together with an in-situ observation of internal structure of the fluid sample in an evaluation process, and a clarification of internal structural change. An observation of an internal structure of a fluid sample 1 in an evaluation process of a rheology property by a rheometer 10 is achieved by generating an optical coherence tomographic image by performing an optical coherence tomography by irradiating a light in infrared region from outside of the rheometer 10 to the fluid sample 1, by inclining an optical axis of light in infrared region irradiating the fluid sample 1 for a predetermined angle within an angular range of 1 to 10 degrees with respect to a normal direction of an observation surface 1A of the fluid sample 1 by the optical coherence tomography imaging device 20, together with an evaluation of a rheology property of the fluid sample 1 containing components different in a refractive index by the rheometer 10.

A method for manufacturing a three-dimensional fired body includes (a) a step of producing a shaping mold using an organic material, the shaping mold having a shaping space which has the same shape as a shaped body having a hollow portion that opens to an outer surface thereof, in which a core corresponding to the hollow portion is integrated with the shaping mold; (b) a step of producing the shaped body in the shaping mold by pouring a ceramic slurry into the shaping space and solidifying the ceramic slurry; (c) a step of drying and then degreasing the shaped body, in which the shaping mold is eliminated in any one of the following stages: before drying, during drying, after drying and before degreasing, during degreasing, and after degreasing of the shaped body; and (d) a step of firing the shaped body to obtain a three-dimensional fired body.

A silicon carbide porous body contains β-SiC particles, Si particles, and metal silicide particles. The maximum particle diameter of the β-SIC particles is not smaller than 15 μm. The content of the Si particles is not lower than 10 mass %. The maximum particle diameter of the Si particles is not larger than 40 μm. Further, an oxide coating film having a thickness not smaller than 0.01 μm and not larger than 5 μm is provided on surfaces of the Si particles.

A method for manufacturing a pillar-shaped honeycomb fired body including: measuring a firing shrinkage at an end surface of a first pillar-shaped honeycomb firing body at every predetermined angle for one round based on a portion that has been located at the center of a die when a green body passes through the die, obtaining a second pillar-shaped honeycomb formed body having a corrected end surface contour by modifying an annular mask used for extrusion molding based on a result of the measuring, and then obtaining a second pillar-shaped honeycomb fired body by performing drying and firing.

A method for the additive production of a ceramic main part has the following steps: providing a slip of ceramic base material particles suspended in a liquid phase; producing a slip layer; orienting the radiation of a laser light source onto a section of the slip layer; evaporating liquid phase out of the slip layer in the section of the slip layer onto which the radiation of the laser light source is oriented or was oriented; forming a section of the ceramic main part in the slip layer in a sinter-free manner; optionally repeating the steps of producing a slip layer, orienting the radiation, evaporating the liquid phase, and forming a section of the main part in a sinter-free manner until the ceramic main part is provided; and separating the ceramic main part from the slip.

Disclosed is a sintering process for ceramic sheets. After biscuit firing and glazing, a green body is placed in a kiln, wherein the temperature of the kiln is controlled such that: when the kiln temperature is 100-400° C., the temperature rise duration is 1-2 hours when the kiln temperature is 400-900° C., the temperature rise duration is 2-3 hours; when the kiln temperature is 900-1100° C., the temperature rise duration must reach 3 hours or more; when the kiln temperature is 1100-1350° C. the temperature rise duration is controlled to be 3-4 hours; and after the temperature reaches 1350° C., heat-preservation cooling is conducted; when the temperature drops to 1230-1270° C., the temperature is raised again to 1290-1310° C.; when the temperature drops again to 880-920° C., the kiln cover is opened for cooling, and the finished product is taken out.

A ceramic substrate and a method for production thereof are provided, in which the ceramic substrate includes a composite of : a first ceramic layer including Sr anorthite and Al.sub.2O.sub.3 or an oxide dielectric with a dielectric constant higher than that of Al.sub.2O.sub.3; and a second ceramic layer including Sr anorthite and cordierite and having a dielectric constant lower than that of the first ceramic layer.