A composition having nanoparticles of a refractory-metal boride and a carbonaceous matrix. The composition is not in the form of a powder. A composition comprising a metal component, boron, and an organic component. The metal component is nanoparticles or particles of a refractory metal or a refractory-metal compound capable of decomposing into refractory metal nanoparticles. The organic component is an organic compound having a char yield of at least 60% by weight or a thermoset made from the organic compound. A method of combining particles of a refractory metal or a refractory-metal compound capable of reacting or decomposing into refractory-metal nanoparticles, boron, and an organic compound having a char yield of at least 60% by weight to form a precursor mixture. A composition having nanoparticles of a refractory-metal boride that is not in the form of a powder.

A composition having nanoparticles of a refractory-metal boride and a carbonaceous matrix. The composition is not in the form of a powder. A composition comprising a metal component, boron, and an organic component. The metal component is nanoparticles or particles of a refractory metal or a refractory-metal compound capable of decomposing into refractory metal nanoparticles. The organic component is an organic compound having a char yield of at least 60% by weight or a thermoset made from the organic compound. A method of combining particles of a refractory metal or a refractory-metal compound capable of reacting or decomposing into refractory-metal nanoparticles, boron, and an organic compound having a char yield of at least 60% by weight to form a precursor mixture. A composition having nanoparticles of a refractory-metal boride that is not in the form of a powder.

Disclosed are fast high-temperature sintering systems and methods. A method of fabrication includes positioning a material at a distance of 0-1 centimeters from a first conductive carbon element and at a distance of 0-1 centimeters from a second conductive carbon element, heating the first conductive carbon element and the second conductive carbon element by electrical current to a temperature between 500 C. and 3000 C., inclusive, and fabricating a sintered material by heating the material with the heated first conductive carbon element and the heated second conductive carbon element for a time period between one second and one hour. Other variations of the fast high-temperature sintering systems and methods are also disclosed. The disclosed systems and methods can quickly fabricate unique structures not feasible with conventional sintering processes.

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.

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.