The present invention provides a solid-state ion capacitor. In the solid-state ion capacitor, the particle number in the thickness direction of the solid electrolyte sandwiched between the electrodes was at least 1 and the average particle number was 80 or less. Further, the solid electrolyte includes particles with D10D90 in the particle diameters of particle size distribution of 0.5 m or more and 100 m or less.

A method of preparing silicon carbide powder is provided, which includes mixing first silicon carbide powder with a liquid silicon carbide precursor, annealing the mixture at a first temperature and converting the silicon carbide precursor to a -phase silicon carbide particulate material, and annealing the material at a second temperature and grain-growing the first silicon carbide powder to second silicon carbide powder using the -phase silicon carbide particulate material.

A method for producing a metal fluoride ceramic, comprising: providing a sedimented compound comprising metal fluoride particles having an average particle size lower than 30 nm and a solvent, partially drying the sedimented compound at a temperature lower than 65 C. until the partially dried compound comprises from 5 wt % to 45 wt % of the solvent, and sintering, for example in air, the partially dried and sedimented compound.

A method of making a sintered ceramic body comprising the steps of disposing a ceramic powder (5) inside an inner volume of a spark plasma sintering tool (1), wherein the tool comprises: a die (2) comprising a sidewall comprising inner and outer walls, wherein the inner wall has a diameter defining the inner volume; upper and lower punches (4,4) operably coupled with the die, wherein each of the punches have an outer wall defining a diameter less than the diameter of the die inner wall, thereby creating a gap (3) between the punches and the inner wall when at least one of the punches are moved within the inner volume, and the gap is from 10 m to 70 m wide; creating vacuum conditions inside the inner volume; moving at least one of the punches to apply pressure to the ceramic powder while heating, and sintering; and lowering the temperature of the sintered body.

An electrolyte sheet for solid oxide fuel cells includes a ceramic plate body containing a cubic zirconia sintered material, wherein, with the ceramic plate body being defined to have nine portions including an outer peripheral portion and a central portion, ceramic grains in each of the nine portions have a median size D.sub.50 of 1.0 m to 4.0 m, and a maximum median size D.sub.50 of the ceramic grains among the nine portions is 1.0 to 1.3 times a minimum median size D.sub.50 of the ceramic grains among the nine portions.

A method of making a sintered ceramic body comprising the steps of disposing a ceramic powder inside an inner volume of a spark plasma sintering tool, wherein the tool comprises: a die comprising a sidewall comprising inner and outer walls, wherein the inner wall has a diameter defining the inner volume; upper and lower punches operably coupled with the die, wherein each of the punches have an outer wall defining a diameter less than the diameter of the die inner wall, thereby creating a gap between the punches and the inner wall when at least one of the punches are moved within the inner volume, and the gap is from 10 m to 70 m wide; creating vacuum conditions inside the inner volume; moving at least one of the punches to apply pressure to the ceramic powder while heating, and sintering; and lowering the temperature of the sintered body.

The invention relates in general to sintering under pressure and with electrical current, often termed spark plasma sintering (SPS). Particular aspects of the invention are directed to a sintering device, a sintering process, a ceramic body product, an assembly comprising the ceramic body and the use of a graphite layer in a sintering process. The invention relates to a device having a sintering chamber, the sintering chamber being bordered by the following device parts: i. a first punch surface of a first punch; ii. a second punch surface of a second punch; and iii. an interior surface of a die; wherein: the punches are adapted and arranged to apply a pressure of at least 1 MPa along a compression axis to a target in the sintering chamber; the first punch and the second punch are connected to an electrical power source.

A process for the preparation of a ceramic body, comprising the steps: a. providing a plurality of particles; b. providing a device that comprises a sintering chamber bordered by a die; c. introducing the particles into the sintering chamber; d. applying a pressure P in the range from 1 MPa to 80 MPa to the plurality of particles in the sintering chamber to obtain the ceramic body, wherein a temperature in the sintering chamber, during preparation of the ceramic body, is controlled so that the temperature at a centre of the sintering chamber is lower than the temperature at an interior surface of the die.