Methods and apparatus for fabricating separators for solid-state lithium metal batteries employ rapid thermal processing. Aspects include high temperature sintering. Temperatures, durations of heat application, and proximity of heating elements to materials undergoing sintering combine to provide separators with desirable physical characteristics, including porosity, in a batch process.

The present invention relates to a method and a device for producing ceramics, the method comprising: radiating light onto a ceramic starting material in order to heat this at least in some regions and, as a result, to produce a ceramic product, wherein the radiation of light is carried out simultaneously on a surface of at least 0.1 mm.sup.2 and/or more than 20% of the surface of the ceramic starting material, and wherein the power density of the radiated light is less than 800 W/cm.sup.2, the device comprising: at least one receiving means for receiving a ceramic starting material andat least one light source for radiating light onto the ceramic starting material that is or can be received in the receiving means, the device preferably being configured to radiate the light onto the ceramic starting material in order to heat this at least in some regions and, as a result, to produce a ceramic product, and wherein the receiving means has an insulation.

Color unevenness generated on a surface of a silicon nitride substrate is reduced. A silicon nitride substrate formed by nitriding silicon containing in a sheet-shaped green body includes a first surface and a second surface opposite to the first surface. In this case, when color difference between a center and an edge of at least one surface of the first surface and the second surface is expressed to be E*ab, a relation E*ab1.5 is established.

Methods and apparatus for fabricating separators for solid-state lithium metal batteries employ rapid thermal processing. Aspects include high temperature sintering. Temperatures, durations of heat application, and proximity of heating elements to materials undergoing sintering combine to provide separators with desirable physical characteristics, including porosity, in a batch process.