Disclosed is a composition having nanoparticles or particles of a refractory metal, a refractory metal hydride, a refractory metal carbide, a refractory metal nitride, or a refractory metal boride, an organic compound consisting of carbon and hydrogen, and a nitrogenous compound consisting of carbon, nitrogen, and hydrogen. The composition, optionally containing the nitrogenous compound, is milled, cured to form a thermoset, compacted into a geometric shape, and heated in a nitrogen atmosphere at a temperature that forms a nanoparticle composition comprising nanoparticles of metal nitride and optionally metal carbide. The nanoparticles have a uniform distribution of the nitride or carbide.

The present invention provides a zirconium nitride powder comprising zirconium, nitrogen, and oxygen as main components, wherein the zirconium concentration is 73 to 82% by mass, the nitrogen concentration is 7 to 12% by mass, and the oxygen concentration is 15% by mass or less; in the transmission spectra of a dispersion having a powder concentration of 50 ppm, a light transmittance X at 370 nm is at least 12% and a light transmittance Y at 550 nm is 12% or less; and the ratio (X/Y) of the light transmittance X at 370 nm to the light transmittance Y at 550 nm is at least 1.4.

The present invention provides a zirconium nitride powder comprising zirconium, nitrogen, and oxygen as main components, wherein the zirconium concentration is 73 to 82% by mass, the nitrogen concentration is 7 to 12% by mass, and the oxygen concentration is 15% by mass or less; in the transmission spectra of a dispersion having a powder concentration of 50 ppm, a light transmittance X at 370 nm is at least 12% and a light transmittance Y at 550 nm is 12% or less; and the ratio (X/Y) of the light transmittance X at 370 nm to the light transmittance Y at 550 nm is at least 1.4.

Provided is a piezoelectric thin film device containing: a first electrode layer; and a piezoelectric thin film. The first electrode layer contains a metal Me having a crystal structure. The piezoelectric thin film contains aluminum nitride having a wurtzite structure. The aluminum nitride contains a divalent metal element Md and a tetravalent metal element Mt. [Al] is an amount of Al contained in the aluminum nitride, [Md] is an amount of Md contained in the aluminum nitride, [Mt] is an amount of Mt contained in the aluminum nitride, ([Md]+[Mt])/([Al]+[Md]+[Mt]) is 36 to 70 atom %. L.sub.ALN is a lattice length of the aluminum nitride in a direction that is approximately parallel to a surface of the first electrode layer with which the piezoelectric thin film is in contact, L.sub.METAL is a lattice length of Me in a direction, and L.sub.ALN is longer than L.sub.METAL.

Provided is a piezoelectric thin film device containing: a first electrode layer; and a piezoelectric thin film. The first electrode layer contains a metal Me having a crystal structure. The piezoelectric thin film contains aluminum nitride having a wurtzite structure. The aluminum nitride contains a divalent metal element Md and a tetravalent metal element Mt. [Al] is an amount of Al contained in the aluminum nitride, [Md] is an amount of Md contained in the aluminum nitride, [Mt] is an amount of Mt contained in the aluminum nitride, ([Md]+[Mt])/([Al]+[Md]+[Mt]) is 36 to 70 atom %. L.sub.ALN is a lattice length of the aluminum nitride in a direction that is approximately parallel to a surface of the first electrode layer with which the piezoelectric thin film is in contact, L.sub.METAL is a lattice length of Me in a direction, and L.sub.ALN is longer than L.sub.METAL.

Disclosed is a composition having nanoparticles or particles of a refractory metal, a refractory metal hydride, a refractory metal carbide, a refractory metal nitride, or a refractory metal boride, an organic compound consisting of carbon and hydrogen, and a nitrogenous compound consisting of carbon, nitrogen, and hydrogen. The composition, optionally containing the nitrogenous compound, is milled, cured to form a thermoset, compacted into a geometric shape, and heated in a nitrogen atmosphere at a temperature that forms a nanoparticle composition comprising nanoparticles of metal nitride and optionally metal carbide. The nanoparticles have a uniform distribution of the nitride or carbide.

A ceramic powder containing at least one of a nitride and a carbonitride of a metal element as a major component, the metal element being one or more elements selected from the group consisting of a group 4 element, a group 5 element and a group 6 element, the ceramic powder having particles having an average particle size of 5 m or less, and an oxygen content of 0.3% by mass or less.

A ceramic powder containing at least one of a nitride and a carbonitride of a metal element as a major component, the metal element being one or more elements selected from the group consisting of a group 4 element, a group 5 element and a group 6 element, the ceramic powder having particles having an average particle size of 5 m or less, and an oxygen content of 0.3% by mass or less.

Provided are composite particles having the optical characteristic of a lower transmittance in the visible light region, i.e., a higher light-blocking performance in the visible light region, and a method for producing composite particles. The composite particles have at least one of Al and Ti formed into a composite with ZrN.

Provided are: composite particles having excellent oxidation resistance; and a method for producing composite particles. The composite particles are obtained by forming a composite of TiN and at least one of Al, Cr, and Nb. In the method for producing composite particles, a titanium powder and a powder of at least one of Al, Cr, and Nb are used as raw material powders and composite particles are produced using a gas phase method.