Other

Nisshin Engineering Inc.

Hoya Corporation

Nisshin Seifun Group Inc.

Kazuhiro Yubuta

Takashi Fujii

Keiichi Nishimura

Sadao Shinozaki

Shintaro Kobayashi

Keitaroh Nakamura

A fine particle producing process introduces a material for producing fine particles into a thermal plasma flame to make a vapor-phase mixture and quenches the vapor-phase mixture to form the fine particles. In the process, the material for producing the fine particles is dispersed or dissolved in a dispersion medium or solvent, preferably containing a combustible material to prepare a dispersion such as a slurry, a colloidal solution or a dissolution solution, the dispersion is made into a form of droplets, or the material for producing the fine particles is dispersed with a carrier gas and a combustible material and the dispersion in a droplet form or the dispersed material is introduced into the thermal plasma flame. In the fine particle producing process and apparatus, a gas of an amount sufficient to quench the vapor-phase mixture is supplied toward a tail of the thermal plasma flame. In the process and apparatus, primary fine particles are introduced into a cyclone to be subjected to cooling and classification and secondary fine particles having a particle size of 100 nm or less which are left upon removal of coarse particles are recovered.

Process and apparatus for producing fine particles

Disclosed herein are a particle production method whereby spherical fine particles of a crystalline calcium phosphate-based compound can be efficiently produced at low cost, fine particles (especially, spherical particles) with good flowability produced by the particle production method, and a high-quality sintered body obtained by sintering a molded body of the particles. The particle production method comprises a first step of mixing a first substance containing phosphorus and a second substance containing calcium so that the phosphorus and the calcium are present in a predetermined mole ratio and feeding, into a heated atmosphere, droplets of a slurry containing an amorphous reaction product, obtained by the reaction between the first substance and the second substance, to bring the reaction product into a gaseous state; and a second step of crystallizing the reaction product in the gaseous state to obtain particles mainly composed of a calcium phosphate-based compound containing phosphorus and calcium in the predetermined mole ratio. The heated atmosphere preferably contains plasma produced by ionization of an ambient gas.

Method for producing particles, particles, and sintered body

The oxide coated fine metal particles include fine core metal particles that are covered with a coating layer including an oxygen-containing compound of a dissimilar element that do not contain as a main component a metal element which is the main component of the fine core metal particles, or a complex oxide or a complex salt of the oxide, the complex oxide or the oxy-acid salt and an oxide of the metal element. A metal powder material is mixed with an oxide powder material of the oxygen-containing compound to obtain a powder material mixture. The powder material mixture is supplied into a thermal plasma to make a vapor-phase mixture and then the vapor-phase mixture is quenched to form the oxide coated fine metal particles comprising the fine core metal particles that are finer than the metal powder material and which are covered with the coating layer including the oxygen-containing compound.

Process for producing oxide coated fine metal particles

The oxides-enclosed fine glass particles are arranged such that two or more pieces of at least two kinds of enclosing particles, which comprise oxides, double oxides, or salts of oxyacids, or double oxides or double salts thereof, are enclosed in each of the fine glass particles. The fine particles can be easily manufactured by mixing a powder material of glass with a powder material of oxides which comprise oxides, double oxides, or salts of oxyacids, or double oxides or double salts thereof that are not made to glass; converting the thus obtained mixture of the materials into a mixture in a vapor-state by supplying the thermal plasma thereto; and quickly cooling the mixture in the vapor-state. Highly-scattered fine particles of oxides can be easily obtained from the fine particles, and thus a plurality of kinds of fine particles of oxides can be evenly and uniformly mixed in a small amount with a mother material without being unevenly scattered.

Growing community of inventors

Saitama, Japan

Kazuhiro Yubuta